CHEMISTRY OF CALOPHYLLUM WALLICHIANUM, SCAPANIA UNDULATA, PLAGIOCHILA COLORANS AND BIOTRANSFORMATION OF NATURAL PRODUCTS HUANG MINGXING NATIONAL UNIVERSITY OF SINGAPORE 2007 ACKNOWLEDGEMENTS I would like to express my sincere gratitude and appreciation to my supervisor, Associate Professor Leslie J. Harrison, for his guidance, patience and encouragement during the past two years. It will be impossible for me to complete my project without your invaluable advice and support. I wish to thank Associate Professor Benito C. Tan in the Department of Biological Science for his invaluable suggestions. I will also thank Associate Professor Teck K. Tan in the Department of Biological Science and Associate Professor Eng Soon Tok in the Department of Physics for every convenience and support they provided. I also would like to thank my friends, Yanmei, Xiaowei, Li Wei, Chiakwu, who help me a lot throughout my project. My appreciation will also give to the technical staff of Department of Chemistry for NMR, MS and XRD analysis, and Ms Chua Ling Lih for the technical support for the biological part of my project. I also want to thank National University of Singapore for financial support and the research scholarship. Finally but not least, I really want to express my deep gratitude to my dear family members, my father, my mother, my brothers and my sister. You always stand behind me and support me. I do want to say thank you to all of you, for your love, understanding and encouragement. Contents Summary I List of Tables III List of Figures IV List of Schemes V Chapter 1 General introduction 1 1.1 Introduction 1 1.2 Natural Products 1 1.3 Biosynthesis of Natural Products 9 1.4 Natural Products in Modern Drug Discovery Chapter 2 Chemistry of Calophyllum wallichianum 12 14 2.1 Introduction 14 2.2 Results and Discussion 17 2.3 Experimental 26 Chapter 3 Chemistry of Scapania undulata 32 3.1 Introduction 32 3.2 Results and Discussion 37 3.3 Experimental 63 Chapter 4 Chemistry of Plagiochila colorans 72 4.1 Introduction 72 4.2 Results and Discussion 74 4.3 Experimental 76 Chapter 5 Biotransformation of Natural Products 78 5.1 Introduction 78 5.2 Results and Discussion 83 5.2.1 Small-scale Screening Experiments 83 5.2.2 Biotransformation of (±)-Camphor by Mucor plumbeus 85 5.2.3 Biotransformation of (±)-Camphor by Aspergillus niger 87 5.3 Experimental 88 References 5.3.1 General Procedure for Biotransformation 88 5.3.2 Biotransformation of (±)-Camphor by Mucor plumbeus 89 5.3.3 Biotransformation of (±)-Camphor by Aspergillus niger 90 93 Summary This thesis deals with the phytochemistry of one ever green tree and two liverworts. The isolation and purification were mainly achieved by the combination of various chromatographic techniques and the structural identifications were mainly dependent on the employment of spectroscopic techniques including Nuclear Magnetic Resonance (1D and 2D NMR), Mass Spectrometry, X-ray Diffraction, etc. Chapter one gives a general background of natural products chemistry. Chapter two to chapter four concern the chemical studies of three plants: Calophyllum wallichianum, Scapania undulata and Plagiochila colorans. The last chapter covers the biotransformation of terpenoids. Phytochemical studies on Calophyllum wallichianum afforded two novel coumarins (74 and 75) along with eight known compounds: cordatolide A (63), cordatolide B (64), 12-O-methylcordatolide B (69), 12-O-methylcalanolide B (70), trapezifolixanthone (71), pseudocordatolide C (72), carpachromene (73) and (+)-epiafzelechin (76). Investigation of Scapania undulata led to the isolation of six novel compounds (119-124) together (-)-ent-longipinanol with (84), five known compound compounds: 110, (-)-longiborneol diplophyllolide A (78), (117), ent-5β-hydroxydiplophyllolide (118). In addition, three compounds (125-127) were also isolated and there have been many evidences indicating that they were degraded labdane-type diterpenoids, but their structural identification still requires further investigation. The last plant studied was Plagiochila colorans, and this research yielded two known sesquiterpenoids: peculiaroxide (139) and gymnomitrol (140). In the studies of terpenoids biotransformation, small scale trial experiments were developed to screen the fungi that are capable to transform the substrates to be investigated, and the selected biotransformation of camphor by Mucor plumbeus and Aspergillus niger afforded three and four mono-hydroxylated products, respectively. Key words: Natural products, Calophyllum wallichianum, Scapania undulata, Plagiochila colorans, Biotransformation List of Tables Table 2-1. 1H, 13C NMR Data and HMBC Correlations of 74 Table 3-1. 1H, 13C NMR Data of 117 and 1H NMR data of ent-Diplophyllolide A Table 3-2. 1H, 13C NMR Data and HMBC Correlations of 119 Table 3-3. 1H, 13C NMR Data and HMBC Correlations of 120 Table 3-4. 1H, 13C NMR Data and HMBC Correlations of 121 Table 3-5. 13C NMR Comparison of 122 and Scapanin B Table 3-6. 1H, 13C NMR Data and HMBC Correlations of 123 Table 3-7. 1H, 13C NMR Data and HMBC Correlations of 124 Table 3-8. 1H, 13C NMR Data and HMBC Correlations of 125 Table 3-9. Comparison of the NMR Data of 120, 125 and 126 Table 3-10. 1H, 13C NMR Data and HMBC Correlations of 126 Table 5-1. GC Data of the Small Scale Trial Experiments List of Figures Figure 2-1 Relative stereochemistry of ring D fragment of 63 Figure 2-2 Key HMBC correlations of compound 74 Figure 2-3 ORTEP diagram of compound 75 Figure 3-1 ORTEP diagram of compound 110 Figure 3-2 Octant projection diagrams of compound 104 Figure 3-3 Key HMBC correlations of compound 119 Figure 3-4 ORTEP diagram of compound 119 Figure 3-5 Key HMBC Correlations of compound 120 Figure 3-6 NOESY correlations of compound 120 Figure 3-7 ORTEP diagram of compound 120 Figure 3-8 Key HMBC Correlations of compound 121 Figure 3-9 NOESY correlations of compound 121 Figure 3-10 ORTEP diagram of compound 122 Figure 3-11 Key HMBC correlations of compound 123 Figure 3-12 ORTEP diagram of compound 123 Figure 3-13 Key HMBC Correlations of 124 Figure 3-14 ORTEP diagram of compound 124 Figure 3-15 Key HMBC correlations of compound 125 Figure 3-16 Key HMBC Correlations of compound 126 List of Schemes Scheme 1-1 Biosynthesis of phloracetophenone (43) Scheme 1-2 Biosynthesis of alternariol (44) Scheme 3-1 Chemical transformation of scapanin A (91) to 110 Scheme 5-1 Hydroxylation of α-ionone (141) with Streptomyces strains Scheme 5-2 Possible metabolic pathway of camphor (157) in the larva of Spodoptera litura Scheme 5-3 Scheme of the biotransformation of camphor with Mucor plumbeus Scheme 5-4 Scheme of the biotransformation of camphor with Aspergillus niger Chapter 1 General Introduction 1.1 Introduction There is a very long history of compounds from living organisms such as plants and animals being utilized by human beings. The employment of these substances in the treatment of human diseases can be traced back to the Sumerian civilization. In ancient Egypt, India, China, etc., a large number of plants had been found to work well to treat some diseases. For example, Ma Huang, or Ephedra spp. (Ephedraceae) was traditionally used as a diaphoretic, anti-asthmatic and diuretic drug i, and Qian Ceng Ta, or Huperzia serrata (Huperziaceae) was employed to treat fever and inflammation ii,iii. In addition, natural occurring compounds have also been used for thousands of years as dyes (e.g. indigo, shikonin), flavours (e.g. vanillin, capsaicin, mustard oils), fragrances (e.g. various essential oils), stimulants (e.g. caffeine, nicotine), hallucinogens (e.g. morphine, cocaine), insecticides (e.g. nicotine, piperine), and so on. 1.2 Natural Products Natural products consist of two categories: primary metabolites and secondary metabolites. Primary metabolites are ubiquitous in living organisms where they play essential roles in the growth, development and reproduction. Carbohydrates, amino acids, lipids, nucleic acids and proteins are typical examples of primary metabolites. Secondary metabolites, however, are chemical compounds that are not strictly necessary for the survival of organisms. However, they often play some essential roles from the perspective of ecology. Many metabolites, for example, have been found to provide defense against predators, parasites and diseases. Common examples of this category of metabolites include terpenoids, alkaloids, flavonoids, and so forth. Compared with primary metabolites, the occurrence of secondary metabolites is rather restricted. However, it is noteworthy that the boundary between primary metabolites and secondary metabolites is sometimes blurred. For example, some fatty acids and sugars are extremely rare and found only in several species, and at the same time, some sterols are found to play essential role for the survival of many organism and therefore must be considered to be primary metabolites. Currently, the concept of natural products is widely considered to be secondary metabolites. Although natural products have been diversely utilized for thousands of years, their modern and systematic studies did not begin until late eighteenth century. The development of modern separation methods, such as various analytical techniques and preparative chromatographic methods made it possible to isolate compounds present in extremely small quantities, whilst the development of spectroscopic techniques such as UV, NMR, MS, CD, etc, leads to the rapid structural elucidation even with trace quantity iv. Natural products do not directly relate to the survival of creatures, their crucial roles in the evolutionary and ecological perspectives, however, have been widely recognized for a long time. In plant kingdom, some natural products serve as attractants to ensure pollination and reproduction, some act to warn and defend against herbivores and some other compounds play significant role in the competition with surrounding plants for light, space and nutrients. At the same time, secondary metabolites are also frequently employed by various animals to communicate, defend and hunt. Some secondary metabolites contribute to the color of flowers, which is a significant means to attract pollinators. At the same time, the blend of different classes of volatile secondary metabolites (mainly monoterpenoids) in plants produces a broad spectrum of scents to behave as attractants. For example, Nicotiana otophora use volatile and fragrant compounds such as α-thujene (1), myrcene (2), limonene (3), 1,8-cineole (4), sabinene (5), etc. to attract pollinating insects, whereas apple (Malus×domestica) uses 2-phenethyl alcohol (6), linalool (7), cis-3-hexenyl acetate (8) and other compounds for the same purpose v. O (1) α-thujene (2) myrcene (3) limonene (4) 1,8-cineole OH OH O O (5) sabinene (6) 2-phenethyl alcohol (7) linalool (8) cis-3-hexenyl acetate On the other hand, many secondary metabolites in plants play essential roles in deterring herbivores due to their bitter or pungent taste. For example, quinine (9), strychnine (10), brucine (11), emetine (12) and sparteine (13) have bitter taste, whilst capsaicin (14) and piperine (15) are pungent alkaloids vi. H N N HO R1 H H3CO R2 N O H O N (9) quinine (10) strychnine: R1 = R2 = H; (11) brucine: R1 = R2 = OCH3 H3CO N H3CO H H N H N H H OCH3 HN OCH3 (12) emetine (13) sparteine H3CO HO O HN N O O O (14) capsaicin (15) piperine However, it should be noted that the taste properties are sometimes not identical for all animals, e.g. some smelly compounds such as 2-thioethanol are strong repellents for humans, but food containing such compounds often attracts geese vii. Furthermore, some secondary metabolites of plants display extreme toxicity, which protects the hosts against the herbivores. For example, Delphinium consolida (Ranunculaceae) contains diterpene alkaloids such as delphinine (16), delcosine (17) and delsoline (18) that are very toxic to animals. R6 R2 OCH3 R1 R5 N R4 R3 OCH3 OCH3 (16) delphinine: R1 = OCH3, R2 = CH3, R3 = H, R4 = COOCH3, R5 = OCOC6H5, R6 = OH; (17) delcosine: R1 = OH, R2 = CH2CH3, R3 = OH, R4 = OH, R5 = OH, R6 = H; (18) delsoline: R1 = OH, R2 = CH2CH3, R3 = OH, R4 = OH, R5 = OCH3, R6 = H. In addition to defending against herbivores, plants also have to compete with surrounding plants to acquire more light, water, space and nutrients, and this competition is termed as allelopathy. A range of secondary metabolites including phenolic acids, glucosinolates, terpenoids, flavonoids and alkaloids have allelopathic activity and these metabolites are capable to inhibit the germination or growth of other plants to ensure the advantageous position of the hosts in the competition. For example, vinblastine (19) and yohumbine (20) from Catharanthus roseus (Apocynaceae) are able to cause temporary abnormalities in cell division of neighboring Vicia faba viii. Other compounds that also exhibit allelopathic activities include cocaine (21) from Erythroxylum coca, strychnine (10) from Strychnos nux-vomica, physostigmine (22) from Physostigma venenosum ix and caffeine (23), theobromine (24) and theophylline (25) from Coffea arabica x. H OH N N C2H5 N OH H H NH N H H COOCH3 C2H5 COOCH3 H3CO N CH3 OCOCh3 H HO COOCH3 (19) vinblastine (20) yohimbine CH3 O N H CH3 N O N O H3C H3COOC H N O CH3 (21) cocaine O H3C O CH3 N CH3 (23) caffeine N CH3 N N N O (22) physostigmine HN O O H N H3C N N N CH3 (24) theobromine O N N CH3 (25) theophylline The employment of secondary metabolites by animals is rather frequent as well. Some insects are able to excrete bitter tasty alkaloids through a reflex bleeding mechanism when they are attacked by predators. For example, coccinellid beetles synthesize many types of defensive alkaloids. The most typical alkaloids include precoccinelline (26) from Coccinella septempunctata, hippodamine (27) from Hippodamia convergens, myrrhine (28) from Myrrha octodecimguttata, propyleine (29) from Propylaea quatuordecimpunctata xi and chilocorine A (30) from Chilocorus cacti xii. H H H N N N H H H H CH3 H CH3 (26) precoccinelline H CH3 (27) hippodamine (28) myrrhine H H O N N H N H CH3 CH3 (29) propyleine (30) chilocorine A In addition, many amphibians such as frogs and toads have been found to produce poisonous substances in their skin secretions for protection against microbial infections and natural predators. For example, five species of Phyllobates (Dendrobatid frogs) are able to excrete rather toxic batrachotoxins such as batrachotoxinin A (31) and batrachotoxin (32) xiii. H3C H3C N H OR (31) batrachotoxinin A: R = H; HO O CH3 (32) batrachotoxin: R = O C O H3C HO H CH3 N H On the other hand, many secondary metabolites are widely employed by animals such as ants and insects for communication with other members. Chemicals that are released by an organism for transmission of a message to other members of the same species are normally regarded as pheromones. The roles are not identical for different pheromones. Some serve as alarm pheromones, and some other may serve as trail pheromones or sex pheromones, etc. For example, Myrmicine ants, Pristomyrmex pungens excrete 6-n-pentyl-2-pyrone (33) from the poison gland to mark their paths, and some other monoterpenoids released such as α-pinene (34), camphene (35), α-phellandrene (36), and α-terpinene (37) were found to slightly increase the trail-following response of this species of ants xiv. O O (33) 6-n-pentyl-2-pyrone (35) camphene (36) α-phellandrene (34) α-pinene (37) α-terpinene Sex pheromones are often volatile, and sometimes the pheromones released by the female can be detected by its potential mate from as far away as 10 km. Examples of characteristic sex pheromones include anabaseine (38) and anabasine (39) from Messor ants, Messor capensis and skatole (40) in Pheidole ants, Pheidole fallax xv. N H N N H N N (38) anabaseine (39) anabasine (40) skatole In addition, secondary metabolites are also used by animals including spiders, snakes, lizards, and so on, for hunting. For example, many neuroactive acylpolyamines have been discovered in the venom of a few spiders. For example, NSTX-3 (41) and CNS 2013 (42) were discovered in Nephila clavata xvi and Dolomedes okefinokensis xvii, respectively. Most spider acylpolyamines are believed to function by blocking glutamate-sensitive calcium channels, but the exact mechanism remains under investigation. O O H N H N N H N H NH2 N H O HO CONH2 (41) NSTX-3 H N H N H N H N O HO (42) CNS 2013 1.3 Biosynthesis of Natural Products There are a huge number of natural products in nature, and they differ greatly in terms of their structures, characteristics and functions in living creatures. However, NH2 the number of building blocks required to biosynthesize these metabolites are surprisingly few. Acetate pathways, shikimate pathways, mevalonate pathways and deoxyxylulose phosphate pathways cover the biosynthesis of most of the secondary metabolites we encounter, and the building blocks of these pathways are acetyl coenzyme A (acetyl-CoA), shikimic acid, mevalonic acid and 1-deoxyxylulose 5-phosphate, respectively. In other words, most of secondary metabolites including terpenoids, alkaloids, phenols, etc. are all based on these four compounds. The acetate pathway leads to the formation of phenols, prostaglandins, macrolide antibiotics as well as various fatty acids and their derivatives at the primary and secondary metabolism interface. The shikimate pathway produces many phenols, cinnamic acid derivatives, lignans and alkaloids, whilst the mevalonate and deoxyxylulose phosphate pathways in combination afford a large number of terpenoid and steroid metabolites1. In most cases, the biological reactions involve coenzyme A esters such as acetyl-CoA，which forms part of a long alkyl chain as in a fatty acid or may be part of an aromatic system such as phenols. Fatty acids are a large group of secondary metabolites that could be found in almost all plants. The fatty acid biosynthesis first of all involves the initial conversion of acetyl-CoA into malonyl-CoA, a reaction involving ATP, CO2 and the coenzyme biotin as the carrier of CO2. The conversion of acetyl-CoA into malonyl-CoA increases the acidity of the α-hydrogens, and therefore provides a better nucleophile for the following Claisen condensation. The successive incorporation of malonyl-CoA together with the following reduction will lead to the extension of the chain length by two carbons (C2 unit) for each cycle, until the required chain length is obtained. For example, the combination of one acetate starter unit with seven malonates would give the C16 fatty acid, palmitic acid [CH3(CH2)7COOH]. However, in fatty acid biosynthesis, if reduction after each condensation step does not happen, the formed poly-β-keto ester may undergo cyclization to form aromatic compounds. For example, one acetate starter group and three malonate chain extension units (C2 unit) could form a C8 polyketo ester, and a following Claisen reaction and enolization will convert this intermediate into phloracetophenone (43). Likewise, alternariol (44), a metabolite from the mould Alternaria tenuis, can be established to be derived from a single C14 polyketide chain which is formed from seven C2 units. O O SCoA SCoA +3 O O malonyl-CoA acetyl-CoA O O SEnz OH O O enolization O HO O OH (43) phloracetophenone Scheme 1-1 Biosynthesis of phloracetophenone (43) O 7 H3C CO2H O O O OH OH O HO OO O O SEnz (44) alternariol Scheme 1-2 Biosynthesis of alternariol (44) In contrast to the extension of C2 unit as stated in the above cases, the terpenoids are derived from C5 isoprene units, but the isoprene units really employed in the biosynthesis are dimethylallyl diphosphate (DMAPP) (45) and isopenetenyl diphosphate (IPP) (46). The combination of DMAPP and IPP yields geranyl diphosphate (GPP) (47), and further extension of C5 unit leads to the formation of farnesyl diphosphate (FPP) (48), geranylgeranyl diphosphate (GGPP) (49), etc. GPP, FPP and GGPP are precursors of monoterpenoids (C10), sesquiterpenoids (C15) and diterpenoids (C20), respectively. There are relatively few acylic compounds such as farnesol (50), geranylgeraniol (51), etc., being derived from only the simple condensation of these C5 units. However, in most cases, these diphosphates precursors will undergo other reactions such as cyclization reactions to finally form the various structurally different terpenoids. OPP OPP (45) DMAPP (46) IPP OPP (47) GPP OPP (48) FPP OPP (49) GGPP OH (50) farnesol OH (51) geranylgeraniol 1.4 Natural Products in Modern Drug Discovery The potent applications of natural products in medicine and pharmacy have drawn people’s interest for a long time. With the development of isolation and structural identification techniques, it became possible to recognize which constituent accounts for a specific biological property, and this greatly accelerated the procedure of drug discovery. Natural products traditionally have played an important role in drug discovery, but the improvement of alternative drug discovery methods such as rational drug design and combinatorial chemistry to some extent threatened natural products drug discovery. However, natural products are still an essential part in drug discovery because they are able to provide a broad array of lead compounds, which is the basis of modern drug discovery. It was reported that at least 21 natural products and natural product-derived drugs have been launched onto the market in the United States, Europe or Japan from 1998 to 2004 xviii. For example, lobeline (52), an alkaloid from Lobelia inflate, is the active constituent of anti-smoking products such as Cig-Ridettes and Citotal, as well as of preparations against bronchial asthma, chronic bronchitis, cough, vascular disorders and insomnia. In addition, byrostatin-1 (53), a natural product that was discovered from Bugula neritina (Bryozoan), is a protein kinase C (PKC) and it has been granted Orphan Drug status by the FDA and designated an Orphan Medicinal Product in Europe for oesophageal cancer xix. H OH H3CO O O O O OH H H OH O OH OH O N HO O H CH3 O HO OCH3 O OH (52) lobeline (53) byrostatin-1 H Chapter 2 Chemistry of Calophyllum wallichianum 2.1 Introduction Calophyllum is a plant genus of tropical evergreen trees in the family Clusiaceae with approximately 200 species. The distribution of this genus of trees is rather wide, and they are found in Madagascar, eastern Africa, South and Southeast Asia, the Pacific islands, and the West Indies as well as South America. Their growth environments vary greatly as well, and a large number of habitats including ridges in mountain forests, coastal swamps, lowland forest and coral cays are suitable for the growth and production of this genus. In terms of the phytochemistry, Calophyllum is a rich source of aromatic compounds. A wide spectrum of xanthone and coumarin derivatives have been reported from this genus, and many coumarin derivatives display anti-HIV activities which imply their potential application for treating HIV xx. Research on C. inophyllum afforded a series of inophyllum type pyranocoumarins such as soulattrolide (54), inophyllum G-1 (55), inophyllum G-2 (56) and inophyllum P (57). Similar studies on C. lanigerrum led to the discovery of a series of calanolide type pyranocoumarins such as calanolide A (58), calanolide E (59), calanolide E2 (60), calanolide F (61), and calanone (62), and the research of C. cordato-oblongum yielded a series of cordatolide type pyranocoumarins including cordatolide A (63), cordatolide B (64) and oblongulide (65) as well as xanthones such as cordato-oblonguxanthone (66), jacareubin (67) and scriblitifolic acid (68) xxi. O O O O O O O O OH OH (54) soulattrolide (55) inophyllum G-1 O O O O O O O O OH OH (56) inophyllum G-2 (57) inophyllum P O O HO O O O O O O OH HO (58) calanolide A (59) calanolide E (enantiomer of 60) (60) calanolide E2 O O O O O HO O O O OH (61) calanolide F (62) calanone O O O O O O O OH O OH (63) cordatolide A (64) cordatolide B O O O H3CO O O O O OH (65) oblongulide (66) cordato-oblonguxanthone O O OH OH O HO O O OH OH COOH (67) jacareubin (68) scriblitifolic acid There have been extensive studies of the chemistry of the genus Calophyllum, and natural products from C. wallichianum will be introduced in this chapter. 2.2 Results and Discussions Phytochemical studies of the hexane extract of C. wallichianum led to the isolation of seven known compounds, cordatolide A (63), cordatolide B (64), 12-O-methylcordatolide B (69), 12-O-methylcalanolide B (70), trapezifolixanthone (71), pseudocordatolide C (72), carpachromene (73), and one novel compound 74. The EtOAc extract of C. wallichianum afforded one known compound (+)-epiafzelechin (76) and one novel compound 75. Cordatolide A (63) Compound 63 was obtained as white needles. C20H22O5; m.p. 106.0–107.0˚C; the 1 H and 13 C NMR spectra indicated that this compound had an ester carbonyl group [δC 160.5 (C-2)] and a trisubstituted double bond [δH 5.92 (1H, s, H-3); δC 151.6 (C-4), 110.6 (C-3)]. In addition, a 2,2-dimethyl-2H-pyrano-ring was indicated by two doublets at 6.60 ppm [1H, d, J = 10.1 Hz; δC 127.2 (C-8)] and 5.53 ppm [1H, d, J = 9.5 Hz; δC 116.4 (C-7)] and two singlets at 1.50 ppm [3H, s; δC 28.0 (C-14)] and 1.49 ppm [3H, s; δC 27.4 (C-15)]. In addition, the doublet-quartet at 3.92 ppm [1H, dq, J = 8.8, 6.3 Hz, H-10; δC 67.1 (C-10)] and the doublet at 4.70 ppm [1H, d, J = 7.5 Hz, H-12; δC 74.0 (C-12] implied the CH3-CH-CH(CH3)-CH-OH fragment. Meanwhile, as shown in Fig. 2-1, the coupling constant of 8.8 Hz (JH-10,11) and 7.5 Hz (JH-11,12) implied the di-axial relationships between H-10 and H-11 and between H-11 and H-12 in ring D. This compound was identified as cordatolide A by comparison of the NMR data with those literature values xxii. 15 14 6 8 4b 8a A 8b O 10 13 O C D 4a 12b B H O 2 O 12a H3C 10 11 O H3C 12 11 16 4 H OH OH 12 H 17 (63) cordatolide A Fig. 2-1 Relative stereochemistry of ring D fragment of 63 Cordatolide B (64) Cordatolide B (64) was obtained as white needles; C20H22O5; m.p. 217.0-218.0˚C; Similar to compound 63, the 1H and 13 C NMR spectra of compound 64 also indicated an ester carbonyl group [δC 161.0 (C-2)], a trisubstituted double bond [δH 5.92 (1H, s, H-3); δC 151.8 (C-4), 110.8 (C-3)], a 2,2-dimethyl-2H-pyrano-ring [δH 6.62 (1H, d, J = 10.1 Hz), 5.52 (1H, d, J = 10.1 Hz), 1.48 (3H, s); 1.47 (3H, s); δC 127.0 (C-8), 116.5 (C-7), 27.8 (C-14), 27.7 (C-15)] and an oxygen bonded tertiary carbon [δH 4.25 (1H, dq, J = 10.1, 5.7 Hz, H-10; δC 73.0 (C-10)]. In addition, for the same reason, the coupling constant of 10.8 Hz (JH-10,11) also implied the di-axial relationship between H-10 and H-11. However, H-12 afforded a doublet at 4.95 ppm [1H, d, J = 3.2 Hz, H-12; δC 61.7 (C-12], whose coupling constant indicated the axial-equatorial relationship between H-11 and H-12, and H-12 therefore must be at equatorial position since H-11 was at axial position. Thus, compound 64 was identified as a diastereoisomer of compound 63. Careful comparison of the NMR data with literature19 revealed that this compound was cordatolide B (64). 15 14 6 O 8 O 4b 8a 8b O O O O 10 13 4 4a 12b O 12a 3 O 12 OH OCH3 16 18 17 (64) cordatolide B (69) 12-O-methylcordatolide B 12-O-methylcordatolide B (69) 12-O-methylcordatolide B (69) was obtained as yellow solid; C21H24O5; m.p. 112.0-113.0˚C; the 1H and 13C NMR spectra were similar to that of cordatolide B (64) as described above, and the groups as shown below could also be observed: an ester carbonyl group [δC 160.7 (C-2)], a trisubstituted double bond [δH 5.92 (1H, d, J = 0.7 Hz, H-3); δC 151.9 (C-4), 110.9 (C-3)] and a 2,2-dimethyl-2H-pyrano-ring [δH 6.62 ppm (d, J = 10.1 Hz), 5.51 ppm (d, J = 10.1 Hz), 1.48 ppm (3H, s), 1.47 ppm (3H, s); δC 126.8 (C-8), 116.5 (C-7), δC 27.8 (C-14), δC 27.7 (C-15)]. Furthermore, the doublet-quartet at 4.30 ppm [1H, dq, J = 10.8, 6.3 Hz, H-10; δC 73.4 (C-10)] and the doublet at 4.55 ppm [1H, d, J = 2.8 Hz, H-12; δC 70.7 (C-12)] also revealed the O-CH(CH3)-CH(CH3)-CH- fragment, and the relative structure of H10, H-11 and H-12 could also be established to be identical to that of cordatolide B (65) based on the coupling constants. However, the singlet at 3.58 ppm [δH 3.58 (3H, s, H-18); δC 59.2 (C-18)] clearly indicated a OCH3 group, which could only be connected to C-12. Thus, the hydroxyl group at C-12 of cordatolide B was replaced by OCH3 group, and this compound was therefore established to be12-O-methylcordatolide B, which could be further confirmed by the comparison of the NMR data with literature valuesxxiii. 12-O-methylcalanolide B (70) 12-O-methylcalanolide B (70) was obtained as yellow solid. C23H28O5; the 1H NMR spectrum was very similar to that of 12-O-methylcordatolide B (69) as elucidated above, and it also revealed a 2,2-dimethyl-2H-pyrano-ring [δH 6.62 (d, J = 10.1 Hz, H-8), 5.51 (d, J = 10.1 Hz, H-7), δH 1.48 (3H, s, H-16), 1.47 (3H, s, H-17)], a tri-substituted double bond [δH 5.94 (s, H-3)], a OCH3 group [δH 3.60 (s, H-20)] and two oxygen bonded tertiary carbons [δH 4.56 (d, J = 2.5 Hz, H-12), 4.27 (dq, J = 10.7, 6.3 Hz, H-10)]. The splitting pattern of H-10 and H-12 again revealed the di-axial relationship between H-10 and H-11 and axial-equatorial relationship between H-11 and H-12 and therefore led to the relative structure of this compound. However, different from 12-O-methylcordatolide B (69), a doublet at 2.56 ppm (3H, d, J = 0.7 Hz) was absent, and at the same time, compound 70 afforded an extra triplet at 1.02 ppm (3H, t, J = 7.5) and two multiplets at 2.89 ppm (2H, m) and 1.65 ppm (2H, m). This information clearly indicated that the methyl group at C-4 was replaced by a n-propyl group compared with 69. Hence, compound 70 was determined to be 12-O-methylcalanolide B, and this was further confirmed by the NMR data comparison with literature values xxiv. This compound was also found in C. lanigerum. 15 16 17 6 5 O 13 O 4b 8 7 4a 4 8a 12b 8b 12a O 10 O 1 6 3 8 5 8a 9 4b OH 9a 4a 1' 1 4 O 2' 2 3 3' 5' O 4' O OH 1'' 12 3'' OCH3 18 20 19 (70) 12-O-methylcalanolide B 4'' 5'' (71) trapezifolixanthone Trapezifolixanthone (71) This compound was obtained as yellow needle; C23H22O5; m.p. 171.0-172.0˚C; the 1 H and 13C NMR spectra showed a chelated hydroxyl group [δH 13.1 (s, OH-1)], a cis double bond [δH 6.75 (d, J = 9.5 Hz), 5.61 (d, J = 9.5 Hz); δC 127.5 (C-2’), 115.7 (C-1’)], a 1,2,3-trisubstituted aromatic ring [δH 7.75 (dd, J = 7.9, 1.9 Hz, H-8), 7.30 (dd, J = 8.2, 1.9 Hz, H-6), 7.24 (t, J = 8.2 Hz, H-7); δC 124.0 (C-7), 119.7 (C-6), 116.8 (C-8)], a one carbonyl group [δC 181.0 (C-9)]. In addition, two doublets at 6.75 ppm [1H, d, J = 9.5 Hz; δC 115.7 (C-1’)] and 5.61 [1H, d, J = 9.5 Hz; δC 127.5 (C-2’)] as well as a singlet at 1.49 ppm [6H, s; δC 28.3 (C-4’, C-5’)] implied a 2,2-dimethyl-2H-pyrano-ring, and the presence of a 2-methylbut-2-enyl group was indicated by two singlets at 1.87 ppm [3H, s; δC 17.9 (C-5’’)] and 1.73 ppm [3H, s; δC 25.6 (C-4’’)] and a broad triplet at 5.23 ppm [1H, br t, J = 6.9 Hz, H-2’’; δC 122.7 (C-2’’)]. Comparison of the NMR data with reference showed that compound 71 was trapezifolixanthone, a xanthone found also in C. trapezifolium xxv and Tovomita brevistaminea xxvi. Pseudocordatolide C (72) This compound was obtained as yellow needles. C20H22O5; The 1H and 13C NMR spectra showed the structural similarity with cordatolide B (69). The groups as shown below were indicated by the NMR data: a carbonyl group [δC 160.4 (C-2)], a trisubstituted double bond [δH 5.84 (1H, s); δC 111.1 (C-3), 154.7 (C-4)] and a 2,2-dimethyl-2H-pyrano-ring [δH 6.76 (1H, d, J = 10.1 Hz), 5.52 (1H, d, J = 10.1 Hz), 1.46 (3H, s), 1.41 (3H, s); δC 126.7 (C-11), 115.4 (C-12), 28.1 (C-16), 27.9 (C-17)]. In addition, there were also two methyl groups [δH 1.34 (3H, d, J = 6.6 Hz), 1.02 (3H, d, J = 7.0 Hz); δC 24.3 (C-14), 16.4 (C-15)] next to tertiary carbon [δC 75.3 (C-6), 34.8 (C-7)] based on their doublet splitting patterns. However, compared with 69, the alkene protons [δH 6.76 (1H, d, J = 10.1 Hz), 5.52 (1H, d, J = 9.8 Hz)] of 72 were clearly more deshielded, and this implies the nearer position of this cis double bond. This compound therefore should be a member of pseudocordatolide class. With regard to the relative stereochemistry of H-6, H-7 and H-8, the coupling constant of 2.5 Hz of JH-6,7 implied that at least one of H-6 and H-7 was at equatorial position., and the coupling constant between H-7 and H-8 (JH-7,8 = 5.9 Hz) also implied one of them was at equatorial position. Unfortunately, this information was still insufficient for the establishment of the relative structure. Comparison of the NMR data with literature values xxvii showed that compound 72 was pseodocordatolide C, a known compound isolated also from Calophyllum lanigerum. 14 15 6 13 O 8 HO 8a 4b 4a 8b O 12b 12a 10 16 4 2 O 1 O 12 17 (72) pseudocordatolide C Carpachromene (73) Carpachromene (73) was obtained as light yellow crystals. C20H16O5; m.p. 239.0-240.0˚C; the 1H NMR spectrum showed a chelated hydroxyl proton [δH 13.1 (1H, s)] and a 1,4-disubstrituted aromatic ring [δH 7.78 (2H, d, J = 8.2 Hz), 6.96 (2H, d, J = 7.9 Hz)]. In addition, two doublets at 6.72 ppm (1H, d, J = 10.1 Hz) and 5.61 ppm (1H, d, J = 10.1 Hz) together with the singlet at 1.47 ppm (6H, s) clearly implied a 2,2-dimethyl-2H-pyrano-ring. Comparison of the NMR data with those literature values revealed that this compound was carpachromene, a flavone observed also in Flindersia leavicarpa xxviii,xxix. OH O O OH O (73) Carpachromene Compound 74 This compound was obtained as white solid. C20H20O5; The 1H and 13 C NMR spectra revealed one ketone carbonyl group [δC 191.3 (C-8)], one ester carbonyl group [δC 160.8 (C-2)], one trisubstituted double bond [δH 5.98 (1H, d, J = 1.3 Hz); δC 111.9 (C-3), 159.8 (C-4)]. In addition, similar to other coumarin derivatives as identified above, a 2,2-dimethyl-2H-pyrano ring was still present according to the two doublets [δH 6.80 (1H, d, J = 10.1 Hz), 5.64 (1H, d, J = 10.1 Hz); δC 128.1 (C-11), 115.0 (C-12)] and two singlets [δH 1.55 (3H, s), 1.50 (3H, s); δC 28.3 (C-18), 28.1 (C-19)]. Two methyl groups [δH 1.56 (3H, d, J = 6.9 Hz), 1.20 (3H, d, J = 6.9 Hz); δC 19.6 (C-14), 9.8 (C-15)] that were next to tertiary carbon could be recognized as well. Table 2-1: 1H, 13C-NMR Data and HMBC Correlations of 74 No. 1 H NMR 13 HMBC correlations 2 J C NMR 3 J 1 2 3 160.8 5.98 (1H, d, J = 1.3 Hz) C-2 C-4a,13 111.9 4 152.1 4a 103.2 4b 154.2 6 4.28 (1H, qd, J = 6.3, 11.9 Hz) C-14 C-8 79.9 7 2.53 (1H, m) C-15,6,8 C-14 47.1 8 191.3 8a 107.3 8b 159.8 10 79.0 11 5.64 (1H, d, J = 10.1 Hz) C-10,12a C-16,17 128.1 12 6.80 (1H, d, J = 10.1 Hz) C-12a C-10,8b,12b 115.0 12a 103.8 12b 154.2 C-4 C-3,4a 24.6 14 2.56 (3H, s) 1.56 (3H, d, J = 6.9 Hz) C-6 C-7, 19.6 15 1.20 (3H, d, J = 6.9 Hz) C-7, C-6,8 9.8 16 1.55 (3H, s) C-17,10 C-11 28.3 17 1.50 (3H, s) C-18,10 C-11 28.1 13 Similar to pseudocordatolide C (72) as described above, the deshielded alkene proton at 6.80 ppm again indicated that this compound was also a pseudocordatolide compound. Careful comparison of the NMR data between compound 74 and pseudocordatolide C revealed their close structural similarity, except the hydroxyl group had converted into carbonyl group according to the resonance at 191.3 ppm. HMBC correlations of this compound as shown in Table 2-1 and Fig. 2-2 confirmed this hypothesis and led to the establishment of the skeleton of the structure: 14 15 6 8 O O 10 16 13 O O 4 4b O 8a 4a 8b 12b 12a 2 O O O O O 12 17 74 Fig. 2-2: Key HMBC correlations of compound 74 The trans- relationship of CH3-14 and CH3-15 was based on the coupling constant of JH-6, 7. The coupling constant of 11.9 Hz revealed that H-6 and H-7 must have di-axial relationship as shown in cordatolide B (64), hence these two methyl groups must be both at equatorial position and therefore had trans- configuration. Compound 75 This compound was obtained as white crystals. C20H22O5; the 1H and 13C NMR spectra were very similar to that of pseudocordatolide C (72) as described above, the characteristic groups belonging to courmarin datives were still present in 75, such as an ester carbonyl group [δC 160.7 (C-2)], a trisubstituted double bond [δH 5.93 (1H, d, J = 1.2 Hz); δC 111.2 (C-3), 155.2 (C-4)] and a 2,2-dimethyl-2H-pyrano-ring [δH 6.83 (1H, d, J = 10.1 Hz), 5.57 (1H, d, J = 10.1 Hz), 1.51 (3H, s), 1.46 (3H, s); δC 127.1 (C-11), 115.6 (C-12), 28.4 (C-16), 28.0 (C-17)]. Similarly, the chemical shift of the characteristic H-12 at 6.83 ppm again implied that this compound was a member of pseudocordatolide class as well. There were also another two methyl groups [δH 1.43 (3H, d, J = 6.9 Hz), 0.82 (3H, d, J = 6.9 Hz); δC 24.4 (C-14), 17.5 (C-15)] next to tertiary carbon [δH 4.41 (1H, qd, J = 6.9, 1.9 Hz), 1.99 (1H, qt, J = 6.9, 1.9 Hz); δC 71.5 (C-6), 36.4 (C-7)] based on their doublet splitting patterns. Despite of the high similarity of the NMR spectrum between compound 75 and 72, their difference of the resonances of H-6, H-7 and H-8 was also clear. Compare with the 2.5 Hz of JH-6,7 and 5.9 Hz of JH-7,8 for 72, the coupling constants both became to 1.9 Hz for 75. Although it was still insufficient to establish the relative stereochemistry of this compound from the coupling constants, it definitely indicated that it had different structure with 72. 14 6 15 13 O 8 HO 8a 4b 8b O 10 16 3 4a 12b 12a O 1 O 12 17 Fig 2-3: ORTEP diagram of compound 75 75 To establish its stereochemistry, crystallization of compound 69 was carried out and the following X-ray analysis led to the diagram as shown in Fig. 2-3, and the structure of this compound therefore was established. It could be observed that the structure was almost identical to pseudocordatolide C (72) except the stereochemistry of C-6, C-7 and C-8, and this structure is novel. Attempts of assignment of the 13C NMR peaks to the structure have been made by comparing with the NMR data of pseudocordatolide C, but it should be noted that this assignment definitely may not be completely correct due to the lack of 2D NMR data. (+)-Epiafzelechin (76) This compound was obtained as yellow solid. C15H14O5; m/z 274.0; [α]D = -27.3 (c=6.73 mg/mL, Acetone); 1H NMR spectra indicated a 1,4-disubstituted aromatic ring [δH 7.35 (2H, d, J = 8.8 Hz), 6.81 (2H, dd, J = 8.8, 1.9 Hz)] and two metaaromatic protons [δH 6.02 (1H, d, J = 2.5 Hz), 5.92 (1H, d, J = 1.9 Hz)]. In addition, the 13C NMR spectra showed that there were two tertiary carbons [δC 78.3 (C-2), 65.6 (C-3)] that were next to oxygen atoms and a secondary carbon [δH 2.86 (1H, dd, J = 16.4, 4.4 Hz), 2.75 (1H, dd, J = 17.0, 3.3 Hz); δC 28.3 (C-4)] that was next to a tertiary carbon (C-3). Furthermore, the two proton of the methylene group coupled to H-3 with the coupling constants of 4.4 Hz and 3.3 Hz, these small values implied that neither of them had di-axial relationship with H-3. Hence, the equatorial position of H-3 could be deduced. Comparison of the NMR data with literature revealed that this compound was (+)-epiafzelechin, a flavan derivative that also present in Cryptolestes pusillus xxx. OH 3' 1 HO 7 8 5 8a 4a 1' O 6' 2 4 5' OH OH 76 (+)-Epiafzelechin 2.3 Experimental Chromatography Thin Layer Chromatography (TLC) was developed on precoated glass TLC plates: normal phase TLC (Merck, Kieselgel 60F254, 250 μm), C18 silica TLC (Whatman, KC18F, 200 μm), DIOL silica (Merck, HPTLC-Fertigplatten DIOL F254S). Analytical TCL plates were visualized with UV light (254 nm) and then stained with I2 vapor. Column Chromatography (CC) was developed on silica gel (40-63 μm, Merck) or on C18 (25-40 μm, Merck) and DIOL (Merck, Lichroprep 40-63 μm). For Gel Permeation Column Chromatography (GPC), Sephadex LH-20 (MeOH:CH2Cl2 = 1:1) was utilized. High Performance Liquid Chromatography (HPLC) was performed on a Shimadzu LC-8A system with RI detection or UV detection. HPLC columns: Lichrosorb 10 DIOL, 250 × 4.60 mm; Luna 5μ C18, 250 × 4.60 mm and Phenomenex partisil 10 silica, 250 × 4.60 mm. Spectroscopy Optical rotations were recorded on Perkin-Elmer 241 SCO 0937 Digital Polarimeter. UV spectra were recorded on a SHIMADZU 1601PC UV-Visible spectrophotometer. IR spectra were recorded on BIO-RAD Excalibur Series FTS 3000. Electron impact (EI) mass spectra were measured with a VG Micromass 7035 instrument. NMR spectra were measured with Bruker DPX 300 [300 MHz (1H) and 75 MHz (13C)] or Bruker AMX 500 [500 MHz (1H) and 125 MHz (13C)] using CDCl3 as solvent unless otherwise stated. Muptiplicities were determined by the DEPT pulse sequence or deduced from 2D HMQC. Coupling constants (J) were measured in Hertz (Hz). X-Ray Diffraction (XRD) data for single crystal structures was recorded on a Bruker AXS SMART APEX CCD X-Ray Diffractometer. Sadabs (Sheldrick 2001) was employed for absorption corrections, λ = 0.71073 Å. Tables of atomic co-ordinates, bonds lengths and angles, anisotropic displacement parameters and hydrogen atom co-ordinates are deposited with the Cambridge Crystallographic Data Center. Melting Points Melting points are recorded on BÜCHI B-540 instruments. 2.7 g of hexane extract of Calophyllum wallichianum leaf was roughly separated by gradient flash column chromatography (CC) (EtOAc:Hexane = 20:80, 50:50, 80:20, 100:0) to give two fractions Fraction 1 Sephadex column procedure was employed at first to get rid of most of the fatty acid and chlorophyll, and three fractions were collected. Fraction 1.1 was mainly fat based on the 1H NMR spectrum and therefore was not further studied. Fraction 1.2 was separated by flash CC (EtOAc:Hexane = 12:88) and the following purification by reversed phase HPLC (C18; MeOH:H2O = 85:15) yielded compound 70 (0.8 mg) and 69 (3.5 mg). Fraction 1.3 was separated by flash CC (EtOAc:Hexane = 10:90), and the obtained fraction was purified by another flash CC (Acetone:Hexane = 20:80) to afford compound 71 (5.3 mg). Fraction 2 Sephadex column procedure was employed as well to remove most of the fat and chlorophyll, and the defatted mixture was applied to flash CC (Aectone:Hexane = 25:75). The obtained fraction 2.2 was separated by flash CC (EtOAc:Hexane = 20:80) to afford compound 72 (180.2 mg) and another two mixtures, one was further purified by flash CC (EtOAc:Hexane = 25:75) to yield compound 74 (0.7 mg) whilst the other was further purified by reversed HPLC (C18; MeOH:H2O = 78:22) to yield 63 (5.3 mg) and 64 (4.3 mg). At the same time, the obtained fraction 2.3 was purified by normal phase HPLC (DIOL, EtOAc:Hexane = 30:70) to give compound73 (2.6 mg). In addition, the ethyl acetate extract of C.wallichianum was investigated as well. 3.0 g of crude extracts were roughly separated by gradient flash CC (Acetone:Hexane = 40:60, 50:50, 60:40, 70:30, 80:20, 90:10, 100:0), and the obtained fraction was defatted by a Sephadex column procedure to yield two fractions. Fraction 1 was purified by normal phase flash CC (EtOAc:Hexane = 25:75) to afford compound 75 (15.1 mg). Fraction 2 was purified by normal phase flash CC (Acetone:Hexane = 55:45) to afford compound 76 (76.8 mg).. Cordatolide A (63) C20H22O5; m.p. 106.0–107.0˚C; 1H NMR (CDCl3) δ 6.60 (1H, d, J = 10.1 Hz), 5.92 (1H, s), 5.53 (1H, d, J = 9.5 Hz), 4.70 (1H, d, J = 7.5 Hz), 3.92 (1H, dq, J = 8.8, 6.3 Hz), 2.57 (3H, s), 1.50 (3H, s), 1.49 (3H, s), 1.45 (3H, d, J = 5.1), 1.13 (3H, d, J = 6.9 Hz); 13 C NMR (CDCl3) δ 160.5 (C-2), 155.2 (C-4b), 154.0 (C-12b), 153.2 (C-8b), 151.6 (C-4), 127.2 (C-8), 116.4 (C-7), 110.6 (C-3), 106.4 (C-8a), 106.3 (C-4a), 104.7 (C-12a), 77.6 (C-6), 74.0 (C-12), 67.1 (C-10), 40.4 (C-11), 28.0 (C-14), 27.4 (C-15), 24.5 (C-17), 18.9 (C-16), 15.1 (C-13) Cordatolide B (64) C20H22O5; m.p. 217.0-218.0˚C; 1H NMR (CDCl3) δ 6.62 (1H, d, J = 10.1 Hz), 5.92 (1H, s), 5.52 (1H, d, J = 10.1 Hz), 4.95 (1H, d, J = 3.2 Hz), 4.25 (1H, dq, J = 10.1, 5.7 Hz), 2.56 (3H, s), 1.48 (3H, s), 1.47 (3H, s), 1.42 (3H, d, J = 6.3 Hz), 1.13 (3H, d, J = 6.9 Hz); 13C NMR (CDCl3) δ 161.0 (C-2), 155.0 (C-4b), 153.4 (C-12b), 153.2 (C-8b), 151.8 (C-4), 127.0 (C-8), 116.5 (C-7), 110.8 (C-3), 106.3 (C-8a), 106.2 (C-4a), 104.9 (C-12a), 77.6 (C-6), 73.0 (C-12), 61.7 (C-10), 38.2 (C-11), 27.8 (C-14), 27.7 (C-15), 24.4 (C-17), 18.8 (C-16), 12.5 (C-13) 12-O-methylcordatolide B (69) C21H24O5; m.p. 112.0-113.0˚C; 1H NMR (CDCl3) δ 6.62 (1H, d, J = 10.1 Hz, H-3), 5.92 (1H, d, J = 0.7 Hz), 5.51 (1H, d, J = 10.1 Hz), 4.55 (1H, d, J = 2.8 Hz), 4.30 (1H, dq, J = 10.8, 6.3 Hz), 3.58 (3H, s), 2.56 (3H, d, J = 0.7 Hz), 1.71 (1H, m), 1.48 (3H, s), 1.47 (3H, s), 1.40 (3H, d, J = 6.3 Hz), 1.14 (3H, d, J = 7.0 Hz); 13C NMR (CDCl3) δ 160.7 (C-2), 154.7 (C-4b), 153.4 (C-12b), 153.3 (C-8b), 151.9 (C-4), 126.8 (C-8), 116.5 (C-7), 110.9 (C-3), 106.2 (C-8a), 104.5 (C-4a), 103.8 (C-12a), 77.5 (C-6), 73.4 (C-10), 70.7 (C-12), 59.2 (C-18), 38.6 (C-11), 27.8 (C-14), 27.7 (C-15), 24.4 (C-17), 19.1 (C-16), 13.2 (C-13). 12-O-methylcalanolide B (70) C23H28O5; 1H NMR (CDCl3) δ 6.62 (1H, d, J = 10.1 Hz, H-8), 5.94 (1H, s, H-3), 5.51 (1H, d, J = 10.1 Hz, H-7), 4.56 (1H, d, J = 2.5 Hz, H-12), 4.27 (1H, dq, J = 10.7, 6.3 Hz, H-10), 3.60 (3H, s, OCH3), 2.89 (2H, m, H-13), 1.65 (2H, m, H-14), 1.48 (3H, s, H-16), 1.47 (3H, s, H-17), 1.40 (3H, d, J = 6.3 Hz, H-18), 1.15 (3H, d, J = 6.9 Hz, H-19), 1.02 (3H, t, J = 7.5 Hz, H-15); 13C NMR (CDCl3) δ 160.9 (C-2), 158.5 (C-4), 153.8 (C-8b), 153.1 (C-12b), 151.4 (C-4b), 126.6 (C-7), 116.6 (C-8), 110.3 (C-3), 106.0 (C-12a), 104.7 (C-8a), 103.2 (C-4a), 77.6 (C-6), 73.4 (C-10), 70.8 (C-12), 59.4 (C-20), 38.7 (C-11), 38.7 (C-13), 27.8 (C-16), 27.9 (C-17), 23.3 (C-14), 19.2 (C-18), 14.1 (C-15), 13.3 (C-19). Trapezifolixanthone (71) C23H22O5; m.p. 171.0-172.0˚C; 1H NMR (CDCl3) δ 13.1 (1H, s), 7.75 (1H, dd, J = 7.9, 1.9 Hz), 7.30 (1H, dd, J = 8.2, 1.9 Hz), 7.24 (1H, t, J = 8.2 Hz), 6.75 (1H, d, J = 9.5 Hz), 5.61 (1H, d, J = 9.5 Hz), 5.23 (1H, br t, J = 6.9 Hz), 3.50 (2H, d, J = 6.9 Hz), 2.17 (1H, s), 1.87 (3H, s), 1.73 (3H, s), 1.59 (3H, s), 1.49 (6H, s); 13C NMR (CDCl3) δ 181.0 (C-9), 158.3 (C-3), 156.1 (C-1), 153.7 (C-4a), 144.4 (C-5), 144.2 (C-4b), 131.6 (C-3’’), 127.5 (C-2’), 124.0 (C-7), 122.7 (C-2’’), 120.9 (C-8a), 119.7 (C-6), 116.8 (C-8), 115.7 (C-1’), 107.0 (C-4), 104.8 (C-2), 103.4 (C-9a), 78.3 (C-3’), 28.3 (C-4’), 28.3 (C-5’), 25.6 (C-4’’), 21.7 (C-1’’), 17.9 (C-5’’). Pseudocordatolide C (72) C20H22O5; 1H NMR (CDCl3) δ 6.76 (1H, d, J = 10.1 Hz), 5.84 (1H, s), 5.52 (1H, d, J = 9.8 Hz), 4.96 (1H, d, J = 5.9 Hz), 4.28 (1H, dq, J = 2.5, 6.6 Hz), 2.45 (3H, s), 1.46 (3H, s), 1.41 (3H, s), 1.34 (1H, d, J = 6.6 Hz), 1.02 (1H, d, J = 7.0 Hz); 13C NMR (CDCl3) δ 160.5 (C-2), 154.8 (C-4), 154.6 (C-8b), 152.8 (C-4b), 150.1 (C-12b), 126.8 (C-11), 115.5 (C-12), 111.2 (C-12a), 109.1 (C-3), 104.0 (C-8a), 102.4 (C-4a), 78.7 (C-10), 75.4 (C-6), 64.4 (C-8), 34.9 (C-7), 28.2 (C-16), 28.0 (C-17), 24.4 (C-13), 16.5 (C-14), 7.6 (C-15) Carpachromene 73 C20H16O5; m.p. 239.0-240.0˚C; 1H NMR (CDCl3) δ 13.1 (1H, s), 7.78 (2H, d, J = 8.2 Hz), 6.96 (2H, d, J = 7.9 Hz), 6.72 (1H, d, J = 10.1 Hz), 6.54 (1H, s), 6.40 (1H, s), 5.61 (1H, d, J = 10.1 Hz), 1.47 (6H, s). Compound 74 C20H20O5; 1H NMR (CDCl3) δ 6.80 (1H, d, J = 10.1 Hz), 5.98 (1H, d, J = 1.3 Hz), 5.64 (1H, d, J = 10.1 Hz), 4.28 (1H, qd, J = 6.3, 11.9 Hz), 2.56 (3H, s), 2.53 (1H, m), 1.56 (3H, d, J = 6.9 Hz), 1.55 (3H, s), 1.50 (3H, s), 1.20 (3H, d, J = 6.9 Hz); 13C NMR (CDCl3) δ 191.3 (C-8), 160.8 (C-2), 159.8 (C-8), 154.2 (C-4b), 154.2 (C-12b), 152.1 (C-4), 128.1 (C-11), 115.0 (C-12), 111.9 (C-3), 107.3 (C-8a), 103.8 (C-12a), 103.2 (C-4a), 79.9 (C-6), 79.0 (C-10), 47.1 (C-7), 28.3 (C-16), 28.1 (17), 24.6 (C-13), 19.6 (C-14), 9.8 (C-15) Compound 75 C20H22O5; 1H NMR (CDCl3) δ 6.83 (1H, d, J = 10.1 Hz), 5.93 (1H, d, J = 1.2 Hz), 5.57 (1H, d, J = 10.1 Hz), 4.62 (1H, d, J = 1.8 Hz), 4.41 (1H, qd, J = 6.9, 1.9 Hz), 2.54 (3H, s), 1.99 (1H, qt, J = 6.9, 1.9 Hz), 1.51 (3H, s), 1.46 (3H, s), 1.43 (3H, d, J = 6.9 Hz), 0.82 (3H, d, J = 6.9 Hz); 1H NMR (Acetone-d6) δ 6.73 (1H, d, J = 9.5 Hz), 5.89 (1H, s), 5.72 (1H, d, J = 10.1 Hz), 4.63 (1H, br s), 4.56 (1H, qd, J = 6.3, 1.9 Hz), 2.56 (3H, d, J = 1.2 Hz), 1.49 (3H, s), 1.45 (3H, s), 1.44 (3H, d, J = 6.3 Hz), 0.76 (3H, d, J = 6.9 Hz); 13C NMR (CDCl3) δ 160.7 (C-2), 155.2 (C-4), 155.0 (C-8b), 153.9 (C-4b), 150.6 (C-12b), 127.1 (C-11), 115.6 (C-12), 111.2 (C-3), 107.8* (C-8a), 103.8* (C-4a), 102.5* (C-12a), 78.4 (C-10), 71.5 (C-6), 65.4 (C-8), 36.4 (C-7), 28.4 (C-16), 28.0 (C-17), 24.4 (C-14), 17.5 (C-15), 9.1 (C-13). (* means the assignment of these signals may be interchangeable) (+)-Epiafzelechin (76) C15H14O5; m/z 274.0; [α]D = -27.3 (c=6.73 mg/mL, Acetone); 1H NMR (Acetone-d6) δ 8.36 (1H, s), 8.21 (1H, s), 8.05 (1H, s), 7.29 (2H, d, J = 8.8 Hz), 6.78 (2H, dd, J = 8.8, 1.9 Hz), 5.99 (1H, d, J = 2.3 Hz), 5.89 (1H, d, J = 2.3 Hz), 4.87 (1H, s), 4.21 (1H, br t, J = 4.3 Hz), 2.86 (1H, dd, J = 16.4, 4.4 Hz), 2.62 (1H, dd, J = 16.6, 3.6 Hz); 13C NMR (Acetone-d6) δ 156.4, 156.3 and 156.2 (C-5, C-7 and C-4’ interchangeable assignments), 155.8 (C-8a), 130.0 (C-1’), 128.0 (C-2’), 128.0 (C-6’), 114.4 (C-3’), 114.4 (C-5’), 98.7 (C-4a) 95.2 (C-6), 94.4 (C-8), 78.3 (C-2), 65.6 (C-3), 28.3 (C-4). Crystallographic data for compound 75 C20H22O5; M.W. 342.38; Monoclinic; Space group P2(1); a = 7.0289(9) Å, b = 24.394(3) Å, c = 10.8950(13) Å; α = 90°, β = 103.8°, γ = 90°; V = 1814.3(4) Å3; Z = 4; Density (calculated) = 1.253 Mg/m3; F(000) = 728; μ = 0.090 mm-1; Data were collected using a crystal size ca. 0.70 × 0.30 × 0.28 mm3. Chapter 3 Chemistry of Scapania undulata 3.1 Introduction Scapania undulata is a leafy liverwort in the family Scapaniaceae of the order Jungermannioideae. S. undulata in different environments often shows different colors, being green in deep shade but developing reddish tints when exposed to sunlight. This species is widely distributed in moist and shady places, most commonly near running water or even under water. Liverworts contain abundant sesquiterpenoids, and this point was also supported by the studies to S. undulata. Sesquiterpenoids are the major constituents of S.undulata. β-longipinene (77) and longiborneol (78) are the dominant sesquiterpenoids in S.undulata: 14 4 15 6 2 8 HO (77) β-longipinene 13 11 1 9 12 10 (78) longiborneol In addition, the research of Adio et al led to the discoveries of (+)-helminthogermacrene (79), (-)-cis-β-elemene (80), (+)-β-isolongibornene (81) and (-)-perfora-1,7,-diene (82) xxxi: H (79) (+)-Helminthogermacrene (80) (-)-cis-β-elemene (81) (+)-β-isolongibornene 14 H 7 9 5 6 11 12 (82) (-)-perfora-1,7,-diene (83) (-)-longifolene 3 1 15 HO 13 (84) (-)-longipinanol Some other sesquiterpenoids isolated from S. undulata were also reported. For example, (-)-longifolene (83) and (-)-longipinanol (84) were isolated from German S.undulata by Nagashima et al xxxii, and from Scotland S.undulata by Dağli et al xxxiii. Despite of the structural diversity of sesquiterpenoids, one of the most common sesquterponoids from S.undulata was cadinane-type terpenoids. For example, (+)-4-muurolen-6α-ol (85), scapanol (86), ent-T-muurolol (87), (+)-epicubenol (88), a peroxy compound (89)2 and sesquiterpenoid (90)3 have been reported. H H H OH (85) (+)-4-muurolen-6α-ol OH H OH (86) scapanol (87) ent-T-muurolol OAc OH H AcO O O O H (88) (+)-epicubenol H (89) (90) Diterpenoids were also found in S. undulata, but so far, almost all of the discovered diterpenoids are labdane-type diterpenoids or their derivatives. For example, scapanin A (91), scapanin G (92), scapanin B (93), diterpenoids 94-100 and 12E,14-labdadiens-8α,11ζ-diol (101) have been reported from European S. undulata xxxiv, and the studies of Japanese S. undulata afforded two dimeric labdane diterpenoids, scapaundulin A (102) and B (103) and three related compounds 104-106 xxxv. 15 16 HO 13 O OH OH 11 20 O 9 1 3 O 17 5 7 H O OH 19 (91) scapanin A (92) scapanin G (93) scapanin B: R1 = O, R2 = R4 = OH, R3 = H2; (94) R1 = H2, R2= R4 = H, R3 = H, β-OH; R4 (95) R1 = R3 = H, β-OH, R2 = R4 = H; R1 (96) R1 = R3 = H, β-OH, R2 = H, R4 = OH; O (97) R1 = O, R2 = H, R3 = H, β-OH, R4 = OH; (98) R1 = H, β-OH, R2 = R4 = H, R3 =H2; R2 (99) R1 = O, R2 = H, R3 = H2, R4 = OH; R3 (100) R1 = H, β-OH, R2 = H, R3 = H2, R4 = OH OH HO O O OH O O OH (101) (102) scapaundulin A OH OH R2 O O O OH R1 HO OH OH (104) R1 = OH, R2 = H; (103) scapaundulin B (105) R1 =H, R2 = OH; (106) R1 = R2 = H The chemical transformations of these labdane-type diterpenoids have been carefully studied as well32. Hydrogenation of scapanin A with hydrogen over Pd/C yielded 14,15-dihydro-scapanin A (107), and this compound was able to be reduced by LiAlH4 to yield the tetrahydro-derivative (108). By contrast, the direct reduction of scapanin A by LiAlH4 produced 1α-hydroxy-derivative (109). At the same time, Jones oxidation of scapanin A broke the C12-C13 double bond to yield γ-lactone (110). Mild hydrogenation of scapanin B afforded 13,14-dihydroscapanin B (111) in the form of C-13 epimers mixture, and by contrast, treatment of LiAlH4 reduced the carbonyl group to yield the corresponding 1α-alcohol (112), whilst the reaction of scapanin B with base led to the formation of a rearrangement product (113). For compound 95, the hydrogenation of this diene yielded two isomeric olefins 13-labdene-8α,11ζ-diol (114) and 12-labdene-8α,11ζ-diol (115). HO HO HO OH OH O O O O OH OH OH (107) (108) (109) O HO HO O HO O OH O O OH O OH (110) OH (111) OH (112) HO HO OH OH O O (113) (114) (115) Aromatic compounds from S. undulata were rather rare, and so far, only one aromatic compound, scapaniapyrone A (116), has been reported xxxvi: HOOC OH OH O O COOH (116) scapaniapyrone A The seasonal and geographical variation of secondary metabolites of S. undulata has been investigated as well. According to a research on the amounts of longiborneol (78), longifolene (83) and longipinanol (84) in the essential oil of this species, the yield of essential oil reached a maximum in March, and the content of longifolene and longiborneol remained relatively constant although it reached a maximum in April, whilst the content of longipinanol increased slowly to 24% from January to April followed by a sharp drop to 3% between April and May xxxvii. 3.2 Results and Discussion The chemistry of Scapania undulata has been studied for almost thirty years, and large number of terpenoids has been reported. The content of some secondary metabolites in plants is often very low, so sometimes these metabolites will not be isolated if the quantity of the plant materials is not large enough. The aim of this research is to find out the minor compound in S. undulata. Scapania undulata was collected from Cevennen, Germany, in August 1987. The dichloromethane (CH2Cl2) extract of this plant material were studied to afford five known sesquiterpenoids, (-)-longiborneol (78), (-)-ent-longipinanol (84), compound 110, diplophyllolide A (117), ent-5β-hydroxydiplophyllolide (118) together with six new compounds 119-124. Three pure compounds, 125-127, were also isolated but their final structural identification requires further investigation. There were evidences indicating that two of them were believed to be also degraded labdane-type diterpenoids. (-)-Longiborneol (78) (-)-Longiborneol (78) was obtained as colorless solid. C15H26O; m/z 222.2; [α]D -20.3 (c = 34.3 mg/mL, Acetone). Its 1H and 13 C NMR data showed four methyl groups [δH 0.89 (s), 0.89 (s), 0.81 (s), 0.78 (s); δC 12.9 (CH3), 22.6 (CH3), 28.8 (CH3), 29.1 (CH3)], five secondary carbons[δC 22.4 (CH2), 26.3 (CH2), 30.2 (CH2), 35.1 (CH2), 40.9 (CH2)] and three tertiary carbons [δC 44.0 (CH), 64.3 (CH), 79.5 (CH)]. In addition, the chemical shift of the peak at 79.5 ppm indicated that this tertiary carbon was next to a hydroxyl group. The NMR data was in good agreement with the literature values of (-)-longiborneol31. As a result, this compound is constructed to be (-)-longiborneol (78). 14 14 4 15 7 9 6 6 2 8 1 HO 9 11 13 11 12 12 5 3 1 13 15 HO 10 (78) (-)-longiborneol (84) (-)-ent-Longipinanol (-)-ent-Longipinanol (84) Compound 84 was obtained as white solid. C15H26O; m/z 220; [α]D -32.7 (c = 16.2 mg/mL, Acetone). Its 1H and 13C NMR spectra revealed four methyl groups [δH 1.32 (3H, s, H-15), 0.91 (3H, s, H-14), 0.90 (3H, s, H-13), 0.89 (3H, s, H-12); δC 25.7 (CH3), 27.1 (CH3), 28.6 (CH3), 31.1 (CH3)], five secondary carbons [δC 21.7 (CH2), 27.9 (CH2) 32.5 (CH2), 39.3 (CH2), 42.6 (CH2)] and three tertiary carbons [δC 40.0 (CH), 52.6 (CH), 52.9 (CH)]. A quaternary carbon at 77.1 ppm implied that this carbon was next to an oxygen atom. The NMR data of compound 84 was found to be the same as that of (-)-ent-longipinanol31, one of the most abundant compounds in S. undulata, and they had the same optical specific rotation sign as well, so this compound was established as (-)-ent-longipinanol. Diplophyllolide A (117) This compound was obtained as colorless oil. C15H20O2; m/z 320.0; [α]D = -26.5 (c = 53.4 mg/mL, Acetone). The 1H and 13C NMR spectra (Table 3-1) of compound 117 indicated the presence of a lactone or ester group [δC 170.6 (C-12)], a tri-substituted alkene [δH 5.36 (1H, m, H-3); δC 132.9 (C-4), 122.3 (C-3)], a C=CH2 group [δH 6.09 (1H, d, J = 1.3 Hz), 5.58 (1H, s); δC 142.0 (C-11), 120.2 (C-13)], one vinyl methyl group [δH 1.60 (3H, s, H-14); δC 17.2 (C-14)] and an oxygen-bonded tertiary carbon [δH 4.50 (1H, m, H-8); δC 77.0 (C-8)]. In addition, this compound also contained another methyl groups [δH 0.87 (3H, s, H-15); δC 21.0 (C-15)] and two tertiary carbons [δC 41.2 (CH), 43.8 (CH)]. The comparison of NMR data between compound 111 and ent-diplophyllolide A (ent-111) xxxviii revealed that these two compounds had the same skeleton as well as relative stereochemistry. 1 15 9 O 10 12 7 5 3 O O O 11 H H 13 14 (117) diplophyllolide A (ent-117) Table 3-1 1H, 13C NMR data of Compound 117 and 1H NMR data of ent-diplophyllolide A (ent-117) No. 1 H of 117 1 H of ent-diplophyllolide A 13 C of 117 1 40.9 CH2 2 22.1 CH2 3 5.36, 1H, m 5.36 1H m 122.3 CH 4 132.9 C 5 41.2 CH 6 27.4 CH2 7 3.00, 1H, m 3.01, 1H, m 43.8 CH 8 4.50, 1H, td, J=5.1, 1.3 4.50, 1H, m 77.0 CH 9 37.8 CH2 10 30.8 C 11 142.0 C 12 170.6 C 13 6.09, 1H, d, J=1.3; 5.58, 1H, s 6.09, 1H, d, J=1.5; 5.58, 1H, d, J=1.5 120.2 CH2 14 1.60, 3H, s 1.61, 3H, s 17.2 CH3 15 0.87, 3H, s 0.88, 3H, s 21.0 CH3 (* The chemical shifts of C-5 and C-7 may be interchangeable.) However, the optical specific rotation of compound 117 was measured to be -26.5˚ compared to that of ent-diplophyllolide A (+132˚), and this opposite specific rotation sign indicated that compound 117 was diplophyllolide A, the enantiomer of ent-diplophyllolide A. ent-5β-Hydroxydiplophyllolide (118) This compound (118) was obtained as white solid. C15H20O3; [α]d = -24.6 (c = 1 89.0 mg/mL, Acetone). The H and 13 C NMR spectra resembled those of Diplophyllolide A (117) as elucidated above, and it also revealed the presence of a lactone or ester group [δC 169.2 (C-12)], a trisubstituted double bond [δC 132.7 (C-4), 122.0 (C-3)], a C=CH2 double bond [δC 145.0 (C-11), 120.3 (C-13)], a vinyl methyl groups [δH 1.58 (3H, s, H-14); δC 16.7 (C-14)], a tertiary methyl group [δH 0.79 (3H, s, C-15); δC 20.9 (C-15)] along with four secondary carbons [δC 37.9 (CH2), 37.5 (CH2), 33.4 (CH2), 21.9 (CH2)]. Compared with the quaternary carbon [δC 30.8 (C)] and three tertiary carbons [δC 77.0 (CH), 41.2 (CH), 43.8 (CH)] of 117, 118 contained two quaternary carbons [δC 75.1 (C), 30.9 (C)] and two tertiary carbons [δC 81.7 (CH), 40.2 (CH)]. This comparison clearly showed that one hydroxyl group had been introduced on one of the three tertiary carbons of 117 to form a tertiary alcohol [δC 75.1 (C)] in 118 whilst the rest part of kept unchanged. Careful comparison of the NMR data with those literature values showed that compound 118 was ent-5β-hydroxydiplophyllolide, a metabolites that was also found in Chiloscyphus polyanthus xxxix. The optical specific rotation of compound 118 was measured be [α]d = -24.6˚, in good agreement with the reference value (-36.1o). 15 1 O 10 8 5 7 3 OH 12 O 11 13 14 (118) ent-5β-hydroxydiplophyllolide Compound 110 Compound 110 was obtained as white crystals. C16H24O5; m/z 296.0; [α]D = +26.6 (c = 7.8 mg/mL). The 1H and 13 C NMR spectra revealed that there were one ketone carbonyl group [δC 217.3 (C-1)], one lactone or ester group [δC 175.3 (C-12)] and two alcohols, one secondary [δH 4.50 (d, J = 12.6 Hz); δC 67.4 (C-11)] and the other tertiary [δC 80.0 (C-5)]. In addition, four tertiary methyl groups [δH 1.41 (s), 1.39 (s), 1.22 (s), 1.09 (s); δC 26.5 (C-18), 26.5 (C-19), 22.9 (C-17), 16.8 (C-20)] and four CH2 groups [δC 35.5 (C-2), 34.2 (C-7), 32.7 (C-3), 27.4 (C-6)] could be recognized as well. There was also a tertiary proton [δH 3.17 (d, J = 12.6 Hz), δC 51.9 (C-9)] coupling to H-11, and the coupling constant indicated that H-9 and H-11 had di-axial relationship as explained in the discussion of cordatolide A (63). Compared with scapanin A (91), a diterpenoid also present in S. undulata as described above, it was found that the only difference of their NMR data was the signals of C-12, C-13, C-14, C-15 and C-16. It could be easily observed that the signals of C-13, C-14, C-15 and C-16 of scapanin A were absent, and C-12 converted from an alkene carbon (δC 156.5) into carbonyl group (δC 175.3). This compound was therefore proposed as structure 110. This compound could be prepared by chemical transformation of scapanin A, in which the double bond between C-12 and C-13 broke down to give a carbonyl group. This transformation was feasible in laboratory as well. As described in the introduction part, treatment of Jones reagent with scapanin A at room temperature led to the production of 110 (Scheme 3-1) xl: HO HO O O O O OH (91) scapanin A O Jones Reagent OH (110) Scheme 3-1 Chemical transformation of scapanin A (91) to 110 Crystallization of compound 110 was carried out in EtOAc, and the following X-ray analysis afforded the diagram as shown in Fig. 3-1, and this directly confirmed the proposed structure. Fig. 3-1 ORTEP diagram of compound 110 However, X-ray analysis was insufficient to tell the absolute stereochemistry of compound 110 due to the lack of heavy atoms, and an alternative technique to achieve its absolute chemistry is Circular Dichroism (CD) spectroscopy. If the absolute structure of this compound was (5R, 8R, 9R, 10R, 11S)-110, this compound was expected to display positive Cotton Effect (CE) based on empirical Octant rule as shown in Fig. 3-2, if the effect of the oxygen atoms could be ignored. The obtained CD spectrum of this compound showed a positive Cotton Effect. Therefore, this compound was tentatively determined to be (5R, 8R, 9R, 10R, 11S)-110, and this absolute stereochemistry was in agreement with reference whose absolute structure was determined by the comparing the CD spectrum with a known compound4. A: (5R, 8R, 9R, 10R, 11S)-110 B: (5S, 8S, 9S, 10S, 11R)-110 Fig. 3-2 Octant projection diagrams of compound 110 Compound 119 Compound 119 was obtained as white crystals. C14H22O3; m/z 238; [α]D = -1.39 (c = 23.8 mg/mL, Acetone). The 13C NMR spectrum of 119 showed the presence of one ketone carbonyl group [δC 215.1 (C)], three methyl groups [δC 33.4 (CH3), 21.8 (CH3), 20.8 (CH3)], four secondary carbons [δC 46.1 (CH2), 27.7 (CH2), 24.6 (CH2), 23.8 (CH2)], three tertiary carbons [δC 75.3 (CH), 40.1 (CH), 38.9 (CH)] and two quaternary carbons [δC 110.9 (C), 81.9 (C)]. In addition, the chemical shift of 75.3 ppm showed that this tertiary carbon was next to an oxygen atom, and so was the quaternary carbon at 81.9 ppm. The peak at 110.9 ppm, however, may indicate that this quaternary carbon connected to two oxygen atoms. This compound may be a degraded sesquiterpenoid in which a C=C bond breaks up to produce a carbonyl group as shown at 215.1 ppm. Table 3-2 1H, 13C NMR Data and HMBC Correlations of 119 No. 1 H 13 HMBC Correlations 2 J C 3 J 1 215.1 2 48.6 3 4 1.74, m C-2,4 C-5,13 1.60, m C-2,4 C-5,12,13 1.72, m 1.69, m 5 20.8 C-5 1.99, brd, J=16.3 1.72, m 40.1 C-4 C-3 6 81.9 7 3.05, dd, J=5.7,1.2 8 1.32, m 1.35, m 9 C-1,6,8 C-9 46.1 21.8 C-9 C-6 2.37, ddd, J=13.2, 13.2, 6.3 1.60, m 33.4 C-14 10 11 38.9 110.9 3.97, d, J=6.9 C-7,10 75.3 3.41, d, J=7.5 C-6 C-5,7 12 1.09, s C-2, C-1,3,13 27.7 13 1.10, s C-2 C-1,3,12 23.8 14 1.45, s C-10 C-9 24.6 H 7 3 10 14 12 1 8 O 13 O O 5 O O O 11 (119) Fig. 3-3 Key HMBC correlations of compound 119 The skeleton of compound 119 could be established according to the HMBC correlations as shown in Table 3-2 and Fig 3-3. Support of the proposed structure was obtained by the X-ray analysis, which yielded the diagram as shown in Fig. 3-4: Fig 3-4 ORTEP diagram of compound 119 Compound 120 Compound 120 was obtained as white crystals. C19H28O5; m.p. 116˚C; [α]D = +170.5 (c = 17.7 mg/mL, Acetone). The 1H and 13 C NMR spectra of this compound were similar to those of 110. The spectra also revealed these fragments: one ketone carbonyl group [δC 217.3 (C)], four secondary carbons [δC 35.5 (CH2), 34.4 (CH2), 32.6 (CH2), 27.6 (CH2)], two tertiary carbons [δH 5.17 (d, J = 9.9 Hz), 3.03 (d, J = 10.7 Hz); δC 52.8 (CH), 69.7 (CH)] and four quaternary carbons [δC 85.3 (C), 79.9 (C), 57.6 (C), 37.5 (C)]. This close similarity may indicate that compound 120 was also a degraded labdane-type terpenoid. However, there were also obvious differences between two compounds. Compared with 110, compound 120 afforded an extra aldehyde group [δH 10.20 (s); δC 192.4 (C)], one carbon-carbon double bond [δC 175.0 (C), 114.4 (C)]. In addition, 120 contained five methyl groups [δH 1.69 (s), 1.36(s), 1.22 (s), 1.20 (s), 1.08 (s); δC 26.8 (CH3), 26.6 (CH3), 23.1 (CH3), 17.1 (CH3), 7.6 (CH3)], one more than that of compound 110. At the same time, the ester carbonyl group [δC 175.3 (C-12)] of 110 was absent in 120. This information implied that these two compounds may had similar skeleton whilst some kind of modification took place at the C-12. Analysis of the HMBC correlations as shown in Table 3-3 and Fig. 3-5 led to the skeleton of this compound: Table 3-3 1H, 13C NMR Data and HMBC Correlations of 120 No. 1 H 13 HMBC 2 J C 3 J 1 2 3 217.3 1.95, m C-3 C-4 1.83, m C-3 C-4,10 2.67; dt; J=17.6,6.9 C-2,4 2.61; ddd; J=17.6,8.9,6.3 C-2,4 35.5 34.4 4 37.5 5 79.9 6 7 1.89, m C-5 C-8 1.77, m C-5 C-10 2.1, m C-6,8 C-5 1.85, m C-8 C-5,9 8 9 32.6 85.3 3.03, d, J=10.7 C-8,10,11 C-7,16,19 10 11 27.6 52.8 57.6 5.17, d, J=9.9 C-12 69.7 12 175.0 13 114.4 14 10.20, s C-13 C-15 192.4 15 1.69, s C-13 C-12,14 7.59 16 1.22, s C-8 C-7,9 23.1 17 1.20, s C-4 C-3,5,18 26.6 18 1.08, s C-4 C-3,5,17 26.8 19 1.36, s C-10 C-5,9 17.1 20 6.38, OH C-11 C-9,12 OHC OHC 14 13 HO 15 HO O O 11 19 H O O 1 9 10 5 3 16 7 OH OH 18 17 Fig. 3-5 Key HMBC correlations of compound 120 (120) The relative stereochemistry of this proposed structure was based on the coupling constants as well as NOESY data (Fig. 3-6). First of all, the coupling constant (J) of H-9 [δH 3.03 (d, J = 10.7)] and H-11 [δH 5.17 (d, J = 9.9 Hz)] indicated their di-axial relationship. In addition, from NOESY spectrum, H-11 correlated to the aldehyde proton [H-14, δH 10.20 (s)], and this indicated that these two protons should be spatially close, which meant that the C=C double bond must posses a trans-configuration. Furthermore, the correlation could be found between the protons of CH3-19 (δH 1.36) and CH3-17 (δH 1.20), hence, these two methyl groups were both at axial position. In addition, H-11 (δH 5.17) correlated to the proton of CH3-19 (δH 1.36) and CH3-16 (δH 1.20), and this information suggested that this proton and the other two correlated methyl groups were all at axial position. O H H CH3 CH3 CH3 CH3 O HO O H H3C OH Fig. 3-6 NOESY correlations of compound 120 The structure of compound 120 was confirmed by the X-ray analysis of this compound, and the obtained diagram was shown in Fig. 3-7. This structure has not been reported before. Fig. 3-7 ORTEP diagram of compound 120 Compound 121 Compound 121 was obtained as white gum. C19H28O5; m/z 336.2; [α]D = +31.2˚ (c = 2.6 mg/mL, Acetone). The 1H and 13 C NMR spectra of this compound showed that this compound was also a degraded labdane-type diterpenoid. Similar to compound 120, The NMR data of this compound also indicated one ketone carbonyl group [δC 217.9 (C-1)], one aldehyde group [δH 10.21 (s); δC 192.2 (C-14)], one C=C double bond [δC 174.4 (C-12), 114.9 (C-13)], five CH3 groups [δH 1.15 (s), 1.46 (s), 1.53 (s), 1.62 (s), 1.70 (s); δC 7.7 (C-15), 17.4 (C-19), 23.6 (C-17), 25.2 (C-16), 31.6 (C-18)] that were bonded to quaternary carbons. Also, four tertiary carbons [δH 5.25 (d, J = 9.4 Hz), 4.69 (m), 2.11 (d, J = 10.1 Hz), 1.40 (d, J = 2.5 Hz); δC 70.0 (C-11), 69.2 (C-6), 59.6 (C-9), 57.3 (C-5)] could be recognized, and the chemical shifts indicated that C-6 and C-11 were oxygen bonded, whilst the splitting patters of the proton resonances clearly showed that C-5, C-9 and C-11 were next to tertiary carbons. Table 3-4 1H, 13C NMR Data and HMBC Correlations of 121 1 No. H 13 HMBC Correlations 2 J C 3 J 1 217.9 2 2.36 dt J=15.1, 4.4 35.0 3.10 m 3 1.80 m 42.6 4 34.0 5 1.40, d, J=2.5 C-18 57.3 6 4.69, br m 69.2 7 2.24, dd, J=13.2, 3.2 46.6 1.95, m 8 85.5 9 2.11, d, J=10.1 C-8 C-5,7,16,19 10 59.6 40.0 11 5.25, d, J=9.4 70.0 12 174.4 13 114.9 14 10.21, s C-13 C-15 192.2 15 1.70, s C-13 C-12,14 7.7 16 1.53, s C-8 C-7,9 25.2 17 1.46, s C-4 C-3,5,18 23.6 18 1.15, s C-4 C-3,5,19 31.6 19 1.62, s C-10 C-5,9, 17.4 2D NMR data were not very good due to the presence of some impurities within the fraction I obtained. However, combining the information from 1D NMR data, it was sufficient to figure out most correlations of this compound as shown in Table 3-4 and Fig. 3-8. If compare the 13 C NMR data of compound 121 with that of compound 120, it could be found that most of the signals were very close. For example, both of them contained a ketone group, lactone group, an aldehyde group, etc. The most significant differences between these two groups of data were the signals of C-5 and C-6. The chemical shift of the quaternary C-5 in compound 120 was 79.9 ppm, which meant that this carbon was next to an oxygen atom. However, the corresponding carbon in compound 121 gave a tertiary carbon resonance at 57.3 ppm. On the other hand, the chemical shift of the secondary C-6 moved from 27.7 ppm in compound 120 to tertiary carbon resonance at 69.2 ppm in compound 121. Except these differences, all other signals were very consistent. As a result, it was highly probable that the only difference between these two compounds was that the OH group moved from C-5 to C-6. This was also supported by the 1H NMR data, because compound 121 gave one extra peak at 4.69 ppm compared with compound 120. This hypothesis was also supported by HMBC correlations of compound 121 as shown in Fig. 3-8: OHC CH3 HO O CH3 O H CH3 OH Fig. 3-8 Key HMBC correlations of compound 121 Similar to what has discussed about compound 120, the trans- configuration of the double bond (C12-C13) was indicated by the NOESY effect observed between H-11 (5.25 ppm) and the aldehyde proton (10.21 ppm). In addition, the coupling constant between H-9 and H-11 (JH-9,11 = 9.5 Hz) again revealed the di-axial relationship between these two protons, and the NOESY effect between H-11 and CH3-19, H-11 and CH3-16, H-2β and H-19, H-2β and H-17 as well as H-9 and H-5 as shown in Fig. 3-9 indicated the relative stereochemistry of this compound. OHC O CH3 HO H O H CH3 O CH3 H 2β CH3 CH3 O CH3 CH3 OH HO H H3C H H H H OH (121) Fig. 3-9 NOESY correlations of compound 121 Compound 122 Compound 122 was obtained as white crystals. C20H32O5; m/z 314; 1H and 13 C NMR spectra revealed that this compound had one carbonyl group [δC 221.0 (C-1)], two olefinic methyl groups [δC 13.1 (C-16), 12.7 (C-15) on a trisubstituted double bond [δH 5.51 (br q, J = 6.3 Hz); δC 117.7 (C-14), 136.4 (C-13)], a secondary-tertiary cyclic ether [δH 2.81 (d, J = 5.6, H-12); δC 88.2 (C-12), 80.9 (C-8)] and three hydroxyl groups, one tertiary [δC 80.7 (C-5)] and the other two secondary [δH 3.96 (m, H-6), 4.07 (dd, J = 10.7, 6.3 Hz, H-11), δC 72.9 (C-11), 72.1 (C-6)]. It was found that the NMR data of compound 122 was quite similar to that of scapanin B (93), a diterpenoid isolated from Scottish S. undulata, and the only difference was the signal of C-6. In scapanin B, it was a secondary carbon with the chemical shift of 28.0 ppm, whilst in compound 122, it became a tertiary carbon with the chemical shift of 72.9 ppm. As a result, a hydroxyl group should be introduced to this position. However, it should be pointed out that in the 13 C NMR comparison as shown in Table 3-5, it was assumed that C-6 was the secondary carbon that converted into tertiary carbon, but actually it was hard to determine exactly which one out of the four secondary carbons of scapanin B had undergone such conversion from only the 13 C NMR data. The 13C NMR signals assignment as shown in Table 3-5 was based on the comparison of the NMR data of 122 to that of scapanin B, and some of the peaks assignment might be interchangeable. The final assignment definitely requires more information such as 2D NMR data. 15 16 13 HO O HO 14 O 20 11 O O 1 3 10 9 5 7 17 17 OH OH 19 18 (122) OH 19 18 (93) scapanin B Table 3-5 13C NMR Comparison of 122 and scapanin B No. 13 13 1 220.9 C 218.5 C 2 34.4 CH2 35.7 CH2 3 38.0 CH2 34.5 CH2 4 31.0 C 37.6 C 5 80.9 C 80.3 C 6 72.8 CH 28.0 CH2 7 27.8 CH2 34.7 CH2 8 80.7 C 80.3 C 9 52.8 CH 52.8 CH 10 58.3 C 57.9 C 11 72.1 CH 71.5 CH 12 88.2 CH 89.2 CH 13 136.4 C 135.2 C 14 117.7 CH 119.9 CH 15 12.7 CH3 12.3 CH3 16 13.1 CH3 13.1 CH3 17 25.5 CH3 25.2 CH3 27.8 CH3 27.0 CH3 19 26.5 CH3 26.7 CH3 20 17.4 CH3 17.3 CH3 18 C of Compound 122 C of scapanin B Recrystallization of compound 122 was carried out in EtOAc, and the X-ray analysis definitely proved that the proposed structure was correct, and a hydroxyl group was introduced to C-6. Fig. 3-10 ORTEP diagram of compound 122 Compound 123 Compound 123 was obtained as white crystals. C16H24O4; m/z 280; The 1H and 13 C NMR spectra of compound 123 were very similar to that of 110, and they also revealed one ketone carbonyl group [δC 218.1 (C-1)], one lactone carbonyl group [δC 174.9 (C-12)], four methyl groups [δH 1.41 (s), 1.31 (s), 1.07 (s), 1.06 (s); δC 31.2 (C-18), 23.5 (C-16), 23.5 (C-17), 15.2 (C-19)], four secondary carbons [δC 38.2 (C-3), 38.1 (C-7), 35.0 (C-2), 21.1 (C-6)]. However, compare with the two tertiary carbons (C-9 and C-11) and four quaternary carbons (C-4, C-5, C-8 and C-10) of 110, 123 contained three tertiary carbons [δH 4.56 (d, J = 12.0), 2.31 (d, J = 11.4 Hz), 1.55 (m); δC 67.6 (C-11), 57.9 (C-9), 52.8 (C-5)] and three quaternary carbons [δC 81.3 (C-8), 51.5 (C-10), 32.3 (C-4)]. This information may indicate that the hydroxyl group at C-5 of 110 was replaced by a hydrogen atom and therefore afforded an extra tertiary carbon. The skeleton of compound 123 was able to be established according to its HMBC correlations as shown in Table 3-6 and Fig. 3-11. O HO O 11 19 12 HO O O O 1 3 10 O 9 5 7 16 H 18 17 (123) Fig. 3-11 Key HMBC correlations of compound 123 The relative configuration of this structure was based on NOE experiments and the 1H NMR of compound 123. The di-axial relationship of H-9 and H-11 was indicated by their big coupling constant (approximately 12.0 Hz). In addition, from the NOE experiments, the correlations were observed between CH3-19 and CH3-16, H-11 and CH3-16, CH3-19 and H-11, CH3-17 and CH3-19, thus, it could be deduced that CH3-16, CH3-17, CH3-19 and H-11 are at β positions. Table 3-6 1H, 13C NMR Data and HMBC Correlations of 123 No. 1 H 13 HMBC Correlations 2 C 3 J J 1 2 3 218.1 2.74, ddd, J=16.4, 8.2, 5.1 C-3 C-4 35.0 2.41, ddd, J=16.4, 8.8, 5.1 C-3 1.86, ddd, J=13.9, 8.8, 3.1 C-2,4 C-5,17,18 38.2 1.70, m C-2,4 C-5,17,18 4 32.3 5 1.55, m, 6 1.55, m 7 C-4 C-17,18,19 21.1 1.95, m C-5 1.70, m C-6 2.05, dt, J=12.0, 2,6 C-6,8 C-5,16 8 9 38.1 81.3 2.13, d, J=11.4 C-8, 10, 11 C-1, 5, 7,12,16,19 10 11 52.8 57.9 51.5 4.56, d, 12.0 C-9, 12 C-10 12 67.6 174.9 13 - - 14 - - 15 - - 16 1.41, s C-8 C-7, 9 23.5 17 1.07, s C-4 C-3, 5, 15 23.5 18 1.06, s C-4 C-3, 5, 14 31.2 19 1.31, s C-10 C-1, 5, 9 15.2 20 5.71 (OH) Fig. 3-12 ORTEP diagram of compound 123 The proposed structure was further confirmed by the X-ray analysis of this compound as shown in Fig. 3-12. Compound 124 Compound 124 was obtained as white crystals. C16H24O4; m. p. 194.7-195.3˚C; m/z 280; [α]D -139.7 (c=2.4 mg/mL, Acetone); The IR spectrum of this compound showed the presence of hydroxyl groups (3489 cm-1, OH stretch), and this was also supported by the 1H and 13 C NMR spectra, which indicated that one was secondary [δH 4.55; δC 67.0 (C-6)] and the other was tertiary [δC 70.4 (C-8)]. In addition, compound 124 also contained one trisubstituted C=C double bond [δH 6.19; δC 166.0 (C-9), 112.7 (C-11)], one ester carbonyl group [δC 175.8 (C-12)] and four methyl groups [δH 1.02 (s) 1.25 (s), 1.55 (s), 1.68 (s); δC 33.6 (C-17), 32.7 (C-19), 24.2 (C-18), 17.5 (C-20)]. Aside from the tertiary carbon of the secondary alcohol, there were another two tertiary carbons, one of which was bonded to oxygen atoms [δH 3.95; δC 85.7 (C-1)]. O O 12 20 1 3 O 11 O 9 10 18 OH 7 5 H 19 CH3 OH OH (124) 17 OH Fig. 3-13 Key HMBC correlations of compound 124 Table 3-7 1H, 13C NMR Data and HMBC Correlations of 124 Position 1 H 13 HMBC C 2 J 3 J 1 3.95, dd, J=11.9, 3.8 C-2,10 C-12,20 85.7 2 2.05, dq, J=13.9, 3.8 C-3 C-10 23.6 C-4 C-1,5 40.9 1.88, m 3 1.56, m 1.36, m C-1,18 4 34.6 5 1.07, d, J=1.9 6 4.55, dd, J=5.1, 3.2 7 2.20, dd, J=14.5, 3.2 C- 4, 6,10, C-6,8 C-1,18,20 52.0 C-8,10 67.0 C-5, 17 49.6 1.88, m 8 70.4 9 166.0 10 40.1 11 6.19, s C-9, 12 C-8,10 12 112.7 175.8 13 - - 14 - - 15 - - 16 - - 17 1.68, s C-8 C-7 33.6 18 1.25, s C-4, C-3,5,19 24.2 19 1.02, s C-4 C-3,5,18 32.7 20 1.55, s C-10 1,5, 17.5 The HMBC correlations as shown in Table 3-7 and Fig. 3-13 could lead to the structure of this compound to be 124. Furthermore, compared with compound 110 as described above, it could be easily recognized that the carbonyl group at C-1 had been converted into a tertiary carbon that was next to an oxygen atom. At the same time, the OH group at C-11 was missing to give a carbon-carbon double bond. It was noteworthy that H-1 had HMBC correlation to C-12 (175.8 ppm), which indicated that in compound 124, the lactone was formed between the carboxylic group (C-12) and the OH group at C-1, rather than between carboxylic group and the OH group at C-8 as in compound 110. Relative stereochemistry of compound 124 was built on NOE experiments. NOE effects between H-1 and H-6, H-6 and CH3-18, CH3-19 and CH3-17, CH3-19 and CH3-20 implied the relative stereochemistry as shown in structure 124. This structure was further confirmed by the X-ray analysis of this compound as shown in Fig. 3-14: Fig. 3-14 ORTEP diagram of compound 124 Compound 125 Compound 125 was obtained as light yellow gum. C19H26O5; m/z 333.9; similar to compound 120 as stated above, the 1H and 13C NMR spectra revealed the presence of these fragments: one ketone carbonyl group [δC 213.1 (C)], one aldehyde group [δH 9.54 (s); δC 194.4 (C)], a carbon-carbon double bond [δC 172.3 (C), 106.3 (C)], five methyl groups [δH 1.81 (s), 1.55 (s), 1.32 (s), 1.20 (s), 1.02 (s); δC 29.8 (C-16), 25.5 (C-18), 22.8 (C-17), 17.5 (C-19), 10.4 (C-15)], four secondary carbons [δC 34.5 (C-2), 34.5 (C-3), 26.7 (C-6), 31.3 (C-7)], one tertiary carbon [δH 3.26 (s); δC 61.0 (C-9)] and five quaternary carbons [δC 107.2 (C-11), 90.0 (C-5), 88.5 (C-8), 54.1 (C-10), 35.7 (C-4)]. The chemical shift of the peak at 172.3 ppm showed that the C=C double bond should bond to an oxygen atoms, whilst the chemical shifts of the quaternary carbons at 90.0 ppm and 88.5 ppm implied that they should be both next to oxygen atoms as well, and the quaternary carbon at 107.2 ppm might be connected to two oxygen atoms. From the HMBC correlations as shown in Table 3-8 and Fig. 3-15, the structure of this compound was tentatively proposed to be also a degraded labdane-type diterpenoid as 125: OHC 14 OH O O OHC 15 13 O 1 10 3 5 18 17 125 OH O 11 19 O O 9 7 16 Fig. 3-15 Key HMBC correlations of compound 125 The relative stereochemistry in the proposed structure was based on its NOESY correlations. CH3-19 (δH 1.32) correlated to CH3-17 (δH 1.20) and CH3-16 (δH 1.55), so they should be at β positions. As shown in Table 3-9, it could also be observed that the NMR data of compound 125 was very similar to that of compound 120, except the tertiary carbon C-11 [δC 69.7 (CH)] in the 120 became quaternary C-11 [δC 107.2 (C)] in 125, so it was reasonable to hypothesize that they should have similar structure, and the only difference may be at C-11. In addition, the formula of 125, C19H26O5, indicated the degree of unsaturation to be 7. Therefore, it was possible that there was one oxygen bridge between C-5 and C-11 as shown in structure 125. Table 3-8 1H, 13C NMR Data and HMBC Correlations of 125 Position 1 H 13 HMBC 2 J C 3 J 1 2 213.1 2.4, m C-3 C-4 34.5 1.47, m 3 2.74; ddd; J=17.0,15.3, 6.3 2.4, m 34.5 C-2,4 4 35.7 5 90.0 6 7 2.07, m C-8 1.86, m C-10 1.97, m C-8 1.86, m C-5 31.3 C-5 8 9 26.7 88.5 3.26, s C-8, 10, 11 C-1, 5, 7, 16 61.0 10 54.1 11 107.2 12 172.3 13 106.3 14 9.54, s 194.4 15 1.81, s C-13 C-12, 14 10.4 16 1.55, s C-8 C-7, 9 29.8 17 1.20, s C4 C-3, 5, 18 22.8 18 1.02, s C-4 C-3, 5, 17 25.5 19 1.32, s C-10 C-1, 5, 9, 17.5 Table 3-9 Comparison of the NMR Data of 120, 125 and 126 No . 120 1 H 1 2 125 13 C H 217.3 1.95, m 35.5 1.83, m 3 1 2.67; dt; 17.6,6.9; 126 13 C 2.61; ddd; 17.6,8.9,6.3; H 213.1 2.4, m, 34.5 1.47, m, 34.4 1 2.74; ddd; 17.0,15.3, 6.3 13 C 211.0 2.7; ddd; 16.3,14.3,6.3 34.2 2.4; ddd; 16.4,4.4,2.5 34.5 2.4, m, 1H 2.3; dt; 13.8,4.4 34.0 1.4; ddd; 13.8,6.3,1.9 4 37.5 35.7 35.6 5 79.9 90.0 90.4 6 1.89, m 27.6 1.77, m 7 2.1, m 9 32.6 1.97, m 10 52.8 2.1, m, 31.3 2.1, m 30.3 1.85, m 88.5 3.26, s 26.2 1.95, m 1.86, m 85.3 3.03, d, J=10.7 26.7 1.86, m 1.85, m, 8 2.07, m 61.0 83.6 3.29, s 57.7 57.6 54.1 54.2 69.7 107.2 99.4 12 175.0 172.3 172.0 13 114.4 106.3 - 11 5.17, d, J=9.9 14 10.20, s 192.4 9.54, s 194.4 - 15 1.69, s 7.59 1.81, s 10.4 - 16 1.22, s 23.1 1.55, s 29.8 1.55, s 30.1 17 1.20, s 26.6 1.20, s 22.8 1.22, s 22.8 18 1.08, s 26.8 1.02, s 25.5 1.06, s 25.4 19 1.36, s 17.1 1.32, s 17.5 1.34, s 17.7 20 6.38 (OH) 3.64 (OH) However, there was still some problem with this proposed structure if consider its 3D conformation. To determine its structure, effort was made to convert compound 125 into other compound that is easier to crystallize. It was reported that Shapiro’s reaction between aldehyde and hydrozide was able to convert ketone into hydrozone, a compound that was easier to crystallize, so reaction between compound 125 and p-toluenesulfonylhydrazide was carried out xli,xlii. Unfortunately, this reaction did not give positive result. Lack of materials prevented further studies to this compound. Compound 126 Compound 126 was obtained as white gum. C16H22O5; [α]D = +3.26 (c = 10.6 mg/mL, Acetone). The 1H and 13C NMR spectra indicated the presence of one ketone group [δC 211.0 (C-1)], one ester or lactone group [δC 172.0 (C-12)], four methyl groups [δH 1.06 (s), 1.22 (s), 1.34 (s), 1.55 (s); δC 30.1 (C-16), 25.4 (C-17), 22.8 (C-18), 17.7 (C-19)], four secondary carbons [δC 26.2 (C-6), 30.3 (C-7), 34.0 (C-3), 34.2 (C-2)], one tertiary carbon [δH 3.29 (s); δC 57.7 (C-9)] and five quaternary carbons [δC 99.4 (C-11), 90.4 (C-5), 83.6 (C-8), 54.2 (C-10), 35.6 (C-4)]. The chemical shift of the quaternary carbons at 90.4 ppm and 83.6 ppm showed that they were both bonded to oxygen atoms, and the one at lower field of 99.4 ppm should connect to two oxygen atoms, similar to what was proposed for compound 125. When several drops of D2O was added in the process of acquiring NMR data of 126, the peak at 3.64 ppm was no longer present, which meant that this was a signal of hydroxyl hydrogen. The HMBC spectrum showed the correlation between this proton and carbon at 57.7 ppm (C-9), 99.4 ppm (C-11) and 172 ppm (C-12), this information indicated that this hydroxyl group was at C-11. From the HMBC correlations of 126 as shown in Table 3-10 and Fig. 3-16, the structure of this compound was tentatively proposed to be 126. HO O 19 1 3 18 O 11 O 10 5 12 O HO O O O O 9 7 16 17 126 Fig. 3-16 Key HMBC Correlations of compound 126 Table 3-10 1H, 13C NMR Data and HMBC Correlations of 126 1 H 2 Position 13 HMBC J C 3 J 1 211.0 2 3 2.7; ddd; J=16.3,14.3,6.3 C-1 2.4; ddd; J=16.4,4.4,2.5 C-1 2.3; dt; J=13.8,4.4 C-2,4 34.2 C-14,15 34.0 1.4; ddd; J=13.8,6.3,1.9 4 35.6 5 90.4 6 7 2.1, m C-5 C-4 1.95, m C-5,7 C-10 2.1, m C-8 C-5,9,13 1.85, m C-6 C-13 8 26.2 30.3 83.6 9 3.29, s C-8, 10, 11 C-1,5,12 57.7 10 54.2 11 99.4 12 172.0 13 - - 14 - - 15 - - 16 1.55, s C-8 C-7, 9 30.1 17 1.06, s C-4 C-3,5,15 25.4 18 1.22, s C-4 C-3,5,14 22.8 19 1.34, s C-10 C-1,5,9 17.7 20 3.64 (OH) C-11 C-9,12 It could be noticed that structure 126 was rather similar to the structure proposed for compound 125 except the double bond between C-12 and C-13 was oxidized to lose the C-13, C-14 and C-15 part, whilst the rest part remained. The comparison of the NMR data of these two compounds as shown in Table 3-9 also supported this hypothesis. If compare the NMR data of this compound with that of compound 123, whose structure was confirmed by X-ray analysis, it could be easily found that most of the signals were quite similar except that the two tertiary carbons at 57.9 ppm (C-5) and 67.6 (C-11) ppm in compound 123 had become into two quaternary carbons at 90.4 ppm (C-5) and 99.4 ppm (C11) in compound 126. This information indicated that compared with compound 123, a hydroxyl group was introduced at C-5 for compound 126. Since the quaternary carbon at C-11 may connect to two oxygen atoms, a bridge between C-5 and C-11 was therefore proposed to fit the formula of C16H22O5. The proposed structure as shown above fits the NMR data well. However, similar to what was discussed about compound 125, there was still some difficulties to form the bridge between C-5 and C-11 if take the 3D conformation of this structure into consideration. Final determination of the structure of this compound still requires more work. Compound 127 Compound 127 was obtained as white crystals. C16H26O6; m/z 314; Some basic fragments deduced from the 1H and 13C NMR spectra included one lactone group [δC 179.1(C)], three secondary hydroxyl groups [δH 4.53 (1H, d, J = 12.6 Hz), 4.10 (1H, dd, J = 3.8, 2.5 Hz), 3.97 (1H, dd, J = 12.0, 5.0 Hz); δC 74.0 (CH), 73.9 (CH), 69.1 (CH)] and four methyl groups [δH 1.58 (3H, s), 1.35 (3H, s), 1.29 (3H, s), 0.94 (3H, s); δC 27.0 (CH3), 25.5 (CH3), 25.5 (CH3), 13.1 (CH3)]. In addition, two quaternary carbons [δC 84.1 (C), 79.4 (C)] that were next oxygen atoms and three secondary carbons [δC 43.6 (CH2), 37.5 (CH2), 26.7 (CH2)] could be recognized as well. O HO OH O OH OH 127 The similar NMR data revealed the structural similarity between 127 and 110. Compared with compound 110, the carbonyl group (δC 216.7) and one of four secondary carbons were missing for compound 127. On the other hand, compound 127 afforded two extra tertiary carbons (δC 74.0, 73.9) that were oxygen bonded. This information clearly showed that the carbonyl group of C-1 at 110 was reduced to yield a secondary alcohol, and one hydroxyl group was introduced to one secondary carbon of 110, and these transformations finally led to 127. However, it should be pointed out that this proposed structure remains further investigations. This structure was mainly based on the 1H and 13 C NMR spectra as well as the comparison between this compound and the established structure of 110. The close NMR spectra indicated that the proposed structure might be reasonable and correct to some extent, but the final confirmation of the proposed structure definitely requires more evidence such as 2D NMR data. In addition, it should be reliable to conclude that there was another secondary alcohol besides OH-1 and OH-11, but actually it was hard to determine the exact position of this hydroxyl group due to the lack of HMQC data, and this also leads to the difficulties in the establishment of its relative stereochemistry. Efforts had been made to crystallize this compound. Unfortunately, the quality of the obtained crystals was not good enough for X-ray analysis. 3.3 Experimental Chromatography Thin Layer Chromatography (TLC) was developed on precoated glass TLC plates: normal phase TLC (Merck, Kieselgel 60F254, 250 μm), C18 silica TLC (Whatman, KC18F, 200 μm), DIOL silica (Merck, HPTLC-Fertigplatten DIOL F254S). Analytical TCL plates were visualized with UV light (254 nm) and then stained with I2 vapor. Column Chromatography (CC) was developed on silica gel (40-63 μm, Merck) or on C18 (25-40 μm, Merck) and DIOL (Merck, Lichroprep 40-63 μm). For Gel Permeation Column Chromatography (GPC), Sephadex LH-20 (MeOH:CH2Cl2 = 1:1) was utilized. High Performance Liquid Chromatography (HPLC) was performed on a Shimadzu LC-8A system with RI detection or UV detection. HPLC columns: Lichrosorb 10 DIOL, 250 × 4.60 mm; Luna 5μ C18, 250 × 4.60 mm and Phenomenex partisil 10 silica, 250 × 4.60 mm. Spectroscopy Optical rotations were recorded on Perkin-elmer 241 SCO 0937 Digital Polarimeter. UV spectra were recorded on a SHIMADZU 1601PC UV-Visible spectrophotometer. CD spectra were recorded on a UV/VISIBLE Spectropolarimeter Jasco J-715 instrument. IR spectra were recorded on BIO-RAD Excalibur Series FTS 3000. Electron impact (EI) mass spectra were measured with a VG Micromass 7035 instrument. NMR spectra were measured with Bruker DPX 300 [300 MHz (1H) and 75 MHz (13C)] or Bruker AMX 500 [500 MHz (1H) and 125 MHz (13C)] using CDCl3 as solvent unless otherwise stated. Muptiplicities were determined by the DEPT pulse sequence or deduced from 2D HMQC. Coupling constants (J) were measured in Hertz (Hz). X-Ray Diffraction (XRD) for single crystal structures was recorded on a Bruker AXS SMART APEX CCD X-Ray Diffractometer. Sadabs (Sheldrick 2001) was employed for absorption corrections, λ = 0.71073 Å. Tables of atomic co-ordinates, bonds lengths and angles, anisotropic displacement parameters and hydrogen atom co-ordinates are deposited with the Cambridge Crystallographic Data Center. Melting Points Melting points are recorded on BÜCHI B-540 instruments. Scapania undulata collected from Cevennen, Germany, in August 1987. 700 g plant materials were ground and extracted by CH2Cl2 to give 36 g crude extract, which was separated roughly by gradient normal phase column chromatography (CC) (70% EtOAc-Hexane and pure MeOH) to give two fractions. From the NMR data, the second fraction that was washed out by pure methanol did not contain interesting constituents and therefore was not further studied. The first fraction was firstly separated by Sephadex column to get rid of most of the chlorophyll and fat, and finally 20 g fraction was obtained, which was further separated by gradient liquid chromatography (EtOAc:Hexane = 0:100, 10:90, 20:80, 30:70, 50:50, 60:40, 70:30, 100:0) to yield six sub-fractions: Fraction 1 This fraction (12g) was eluted by hexane, and it mainly consisted of some very non-polar compounds including hydrocarbons. 3 g of this fraction was take to apply on a normal phase liquid CC (EtOAc:Hexane = 0, 5:95, 10:90, 30:70) and compound 117 (53.4 mg) was collected directly. Further purification of other fractions by flash CC afforded three compounds: 78 (270 mg), 84 (20 mg) and 119 (6.0 mg). Fraction 2 This fraction was mainly fat based on its 1H NMR spectrum so was not further studied. Fraction 3 The fraction was separated by normal phase flash column chromatography, and further purified through normal phase CC (Acetone:Hexane = 18:72) to afford compound 118 (167 mg). Fraction 4 Fr. 4 was separated firstly through two normal phase liquid chromatography operations, and further purification by reversed-phase CC (MeOH:H2O = 70:30) yielded two compounds: 125 (5.3mg) and 126 (8.9mg). Structures of these two compounds were proposed to be degraded labdane-type diterpenoids, but the final structural identifications still require further investigation. Fraction 5 Fr. 5 was separated by normal phase liquid chromatography to afford five sub-fractions. A more delicate flash CC (Acetone:Hexane = 30:70) was applied to the first and fourth sub-fractions to yield two pure compounds: 120 (37.8mg) and 122 (3.1 mg). At the same time, the third sub-fraction (100.5mg) was purified by a normal phase CC (Acetone:Hexane = 30:70), followed by a reversed-phase CC (MeOH:H2O = 70:30), and finally one compound 121 (1.0 mg) was collected. The purification of the fifth sub-fractions by flash CC (Acetone:Dichloromethane = 5:95) yielded 123 (0.9 mg). Fraction 6 Fr. 6 was separated by normal phase liquid chromatography (EtOAc:Hexane = 55:45), and the sub-fractions were further purified by normal phase CC to give three pure compounds: 110 (7.8mg), 124 (2.4 mg) and 127 (34.2 mg). (-)-Longiborneol (78) C15H26O; m/z 222.2; [α]D -20.3 (c = 34.3 mg/mL, Acetone); 1H NMR (CDCl3) δ 3.70 (1H, dd, J = 4.9, 1.8 Hz, H-1), 1.83 (1H, m, H-10), 1.79 (1H, d, J = 4.5 Hz, H-8); 1.62 (1H, m, H-9), 1.17 (1H, m, H-10), 0.93 (1H, d, J = 4.9 Hz, H-2), 0.89 (6H, s, H-14, H-15), 0.81 (3H, s, H-12), 0.78 (3H, s, H-13); 13 C NMR (CDCl3) δ 79.5 (C-1), 64.3 (C-2), 51.2 (C-11), 50.0 (C-7), 44.0 (C-8), 40.9 (C-4), 35.1 (C-6), 33.3 (C-3), 30.2 (C-9), 29.1 (C-14), 28.8 (C-15), 26.3 (C-10), 22.6 (C-13), 22.4 (C-5), 12.9 (C-12) (-)-ent-Longipinanol (84) C15H26O; m/z 220; [α]D -32.7 (c = 16.2 mg/mL, Acetone); 1H NMR (CDCl3) δ 1.32 (3H, s, H-15), 0.91 (3H, s, H-14), 0.90 (3H, s, H-13), 0.89 (3H, s, H-12); 13 C NMR (CDCl3) δ 77.1 (C-3), 52.9 (C-2), 52.6 (C-1), 42.6 (C-10), 40.0 (C-6), 39.9 (C-7), 39.3 (C-4), 32.5 (C-8), 32.2 (C-11), 31.1 (C-15), 28.6 (C-13), 27.9 (C-5), 27.1 (C-12), 25.7 (C-14), 21.7 (C-9) Compound 110 C16H24O5; m/z 296.0; [α]D +26.6 (c = 7.8 mg/mL); 1H NMR (CDCl3): δ 6.09 (1H, s, OH), 3.48 (1H, s, OH), 4.50 (1H, d, J = 12.6 Hz), 3.17 (1H, d, J = 12.6 Hz), 2.67 (1H, dt, J = 17.6, 6.9 Hz), 2.59 (1H, ddd, J = 17.6, 8.2, 6.3 Hz), 2.07 (1H, dt, J = 12.6, 5.1 Hz), 1.96 (2H, m), 1.85 (2H, m), 1.41 (3H, s), 1.39 (3H, s), 1.22 (3H, s), 1.09 (3H, s); 13 C NMR (CDCl3): δ 216.7 (C-1), 175.3 (C-12), 35.5 (C-2), 80.7 (C-8), 80.0 (C-5), 67.4 (C-11), 56.7 (C-10), 51.9 (C-9), 37.6 (C-4), 34.2 (C-7), 32.7 (C-3), 27.4 (C-6), 26.5 (C-14), 26.5 (C-15), 22.9 (C-13), 16.8 (C-16). Diplophyllolide A (117) C15H20O2; m/z 320.0; [α]D = -26.5 (c = 53.4 mg/mL, Acetone); 1H NMR (CDCl3) δ 6.11 (1H, d, J = 1.3 Hz), 5.58 (1H, s), 5.36 (1H, br s), 4.50 (1H, td, J = 5.1, 1.3 Hz), 3.00 (1H, m), 1.60 (3H, s), 0.87 (3H, s); 13 C NMR (CDCl3) δ 170.6 (C-12), 142.0 (C-11), 132.9 (C-4), 122.3 (C-3), 120.2 (C-13), 77.0 (C-8), 43.8 (C-7), 41.2 (C-5), 40.9 (C-1), 37.8 (C-9), 30.8 (C-10), 27.4 (C-6), 22.1 (C-2), 21.0 (C-15), 17.2 (C-14). ent-5β-Hydroxydiplophyllolide (118) C15H20O3; [α]d = -24.6 (c = 89.0 mg/mL, Acetone); 1H NMR (CDCl3) δ 6.11 (1H, s), 5.75 (1H, s), 5.30 (1H, br s), 4.25 (1H, d, J = 4.4 Hz), 2.27 (1H, d, J = 1.2 Hz), 1.58 (3H, s), 0.81 (3H, s); 13C NMR (CDCl3) δ 169.2 (C), 145.0 (C), 132.7 (C), 122.0 (CH), 120.3 (CH2), 81.7 (CH), 75.1 (C), 40.2 (CH), 37.9 (CH2), 37.5 (CH2), 33.4 (CH2), 30.9 (C), 21.9 (CH2), 20.9 (CH3), 16.7 (CH3). Compound 119 C14H22O3; m/z 238; [α]D = -1.39 (c = 23.8 mg/mL, Acetone); 1H NMR (CDCl3) δ 3.97 (1H, d, J = 6.9 Hz), 3.41 (1H, d, J = 7.5 Hz), 3.05 (1H, dd, J = 5.7, 1.2 Hz), 2.38 (1H, m), 1.45 (3H, s), 1.10 (3H, s), 1.09 (3H, s); 13 C NMR (CDCl3) δ 215.1 (C-1), 110.9 (C-10), 81.9 (C-6), 75.3 (C-11), 48.6 (C-2), 46.1 (C-7), 40.1 (C-5), 38.9 (C-3), 33.4 (C-9), 27.7 (C-12), 24.6 (C-14), 23.8 (C-13), 21.8 (C-8), 20.8 (C-4). Compound 120 C19H28O5; m.p. 116˚C; [α]D = +170.5 (c = 17.7 mg/mL, Acetone); 1H NMR (CDCl3) δ 10.20 (1H, s), 6.38 (1H, s), 5.17 (1H, d, J = 9.9 Hz), 3.03 (1H, d, J = 10.7 Hz), 2.67 (1H, dt, J = 17.6, 6.9 Hz), 2.61 (1H, ddd, J = 17.6, 8.9, 6.3 Hz), 2.1 (1H, m), 1.95 (1H, m), 1.89 (1H, m), 1.85 (1H, m), 1.83 (1H, m), 1.77 (1H, m), 1.60 (3H, s), 1.36 (3H, s), 1.22 (3H, s), 1.20 (3H, s), 1.08 (3H, s); 13 C NMR (CDCl3) δ 217.3 (C-1), 192.4 (C-14), 175.0 (C-12), 114.4 (C-13), 85.3 (C-8), 79.9 (C-5), 69.7 (C-11), 57.6 (C-10), 52.8 (C-9), 37.5 (C-4), 35.5 (C-2), 34.4 (C-3), 32.6 (C-7), 27.6 (C-6), 26.8 (C-18), 26.6 (C-17), 23.1 (C-16), 17.1 (C-19), 7.6 (C-15). Compound 121 C19H28O5; m/z 336.2; [α]D = +31.2˚ (c = 2.6 mg/mL, Acetone); 1H NMR (CDCl3) δ 10.21 (1H, s, H-14), 5.25 (1H, d, J = 9.4 Hz, H-11), 4.69 (1H, m, H-6), 3.10 (1H, m), 2.36 (1H, dt, J = 15.1, 4.4 Hz), 2.24 (1H, dd, J = 13.2, 3.2 Hz), 2.11 (1H, d, J = 10.1 Hz, H-9), 1.95 (1H, m), 1.70 (3H, s, H-15), 1.62 (3H, s, H-19), 1.53 (3H, s, H-16), 1.46 (3H, s, H-17), 1.40 (1H, d, J = 2.5 Hz, H-5), 1.15 (3H, s, H-18); 13 C NMR (CDCl3) δ 217.9 (C-1), 192.2 (C-14), 174.4 (C-12), 114.9 (C-13), 85.5 (C-8), 70.0 (C-11),69.2 (C-6), 59.6 (C-9), 57.3 (C-5), 46.6 (C-7), 42.6 (C-3), 40.0 (C-10), 35.0 (C-2), 34.0 (C-4), 31.6 (C-18),25.2 (C-16), 23.6 (C-17), 17.4 (C-19), 7.7 (C-15). Compound 122 C20H32O5; m/z 352.4; 1H NMR (DMSO-d6) δ 5.51 (1H, br q, J = 6.3 Hz), 4.07 (1H, dd, J = 10.7, 6.3 Hz), 3.96 (1H, m), 3.87 (1H, dd, J = 5.6 Hz), 2.81 (1H, d, J = 10.7), 1.59 (3H, s), 1.55 (3H, d, J = 6.3 Hz), 1.49 (3H, s), 1.41 (3H, s), 1.30 (3H, s), 1.01 (3H, s); 13 C NMR (DMSO-d6) 220.9 (C-1), 136.4 (C-13), 117.7 (C-14), 88.2 (C-12), 80.9 (C-8), 80.7 (C-5), 72.8 (C-11), 72.1 (C-6), 58.4 (C-10), 52.8 (C-9), 43.6* (C-7), 38.0* (C-3), 34.4* (C-2), 31.0 (C-4), 27.8 (C-19), 26.5 (C-18) 25.5 (C-17),17.4 (C-20), 13.1 (C-15), 12.7 (C-16) (* means these resonances are interchangeable). Compound 123 C16H24O4 m/z 280; 1H NMR (CDCl3) δ 4.65 (1H, d, J = 12.0 Hz), 2.75 (1H, ddd, J = 16.4, 8.2, 5.1 Hz), 2.42 (1H, ddd, J = 18.4, 8.8, 5.1 Hz), 2.15 (1H, d, J = 11.4 Hz), 2.06 (1H, dt, J = 12.0, 3.1 Hz), 1.86 (1H, ddd, J = 13.9, 8.9, 5.1 Hz), 1.71 (1H, m), 1.41 (3H, s), 1.31 (3H, s), 1.07 (3H, s), 1.06 (3H, s); 13C NMR (CDCl3) δ 218.1 (C-1), 174.9 (C-12), 81.3 (C-8), 67.6 (C-11), 57.9 (C-9), 52.8 (C-5), 51.5 (C-10), 38.2 (C-3), 38.1 (C-7), 35.0 (C-2), 32.3 (C-4), 31.2 (C-18), 23.5 (C-16), 23.5 (C-17), 21.1 (C-6), 15.2 (C-19). Compound 124 C16H24O4; m/z 280; [α]D -139.7 (c=2.4 mg/mL, Acetone); m. p. 194.7-195.3˚C; 1H NMR (CDCl3) δ 6.19 (1H, s, H-11), 4.55 (1H, dd, J = 5.1, 3.2 Hz, H-6), 3.95 (1H, dd, J = 11.9, 3.8 Hz, H-1), 2.20 (1H, dd, J = 14.5, 3.2 Hz), 2.05 (1H, dq, J = 13.9, 3.8 Hz), 1.88 (2H, m, H-2), 1.68 (3H, s, H-13), 1.56 (1H, m, H-3), 1.55 (3H, s, H-16), 1.36 (1H, m), 1.25 (3H, s, H-14), 1.07 (1H, d, J = 1.9 Hz, H-5), 1.02 (3H, s, H-15); 13 C NMR (CDCl3) δ175.8 (C-12), 166.0 (C-9), 112.7 (C-11), 85.7 (C-1), 70.4 (C-8), 67.0 (C-6), 40.9 (C-3), 52.0 (C-5), 49.6 (C-7), 40.1 (C-10), 34.6 (C-4), 33.6 (C-13), 32.7 (C-15), 24.2 (C-14), 23.6 (C-2), 17.5 (C-16). Compound 125 C19H26O5; m/z 333.9; 1H NMR (CDCl3) δ 9.54 (1H, s), 3.26 (1H, s), 2.74 (1H, ddd, J = 17.0, 15.3, 6.3 Hz), 2.41 (2H, m), 2.07 (1H, m), 1.97 (1H, m), 1.86 (2H, m), 1.81 (3H, s), 1.55 (3H, s), 1.47 (1H, ddd, J = 17.6, 9.5, 3.1 Hz), 1.32 (3H, s) 1.20 (3H, s), 1.02 (3H, s); 13 C NMR (CDCl3) δ 213.1 (C-1), 194.4 (C-14), 172.3 (C-12), 107.2 (C-11), 106.3 (C-13), 90.0 (C-5), 88.5 (C-8), 61.0 (C-9), 54.1 (C-10), 35.7 (C-4), 34.5 (C-2), 34.5 (C-3), 31.3 (C-7), 29.8 (C-16), 26.7 (6), 25.5 (C-18), 22.8 (C-17), 17.5 (C-19), 10.4 (C-15). Compound 126 C16H22O5; [α]D = +3.26 (c = 10.6 mg/mL, Acetone); 1H NMR (CDCl3) δ 3.64 (1H, s), 3.29 (1H, s), 2.72 (1H, ddd, J = 16.3, 14.3, 6.3 Hz), 2.41 (1H, ddd, J = 16.4, 4.4, 2.5 Hz), 2.31 (1H, dt, J = 4.4, 13.8 Hz), 2.08 (2H, m), 1.95 (1H, m), 1.85 (1H, m), 1.55 (3H, s), 1.43 (1H, ddd, 13.8, 6.3, 1.9 Hz), 1.34 (3H, s), 1.22 (3H, s), 1.06 (3H, s); 13C NMR (CDCl3) δ 211.0 (C-1), 172.0 (C-12), 99.4 (C-11), 90.4 (C-5), 83.6 (C-8), 57.7 (C-9), 54.2 (C-10), 35.6 (C-4), 34.2 (C-2), 34.0 (C-3), 30.3 (C-7), 30.1 (C-16), 26.2 (C-6), 25.4 (C-18), 22.8 (C-17), 17.7 (C-19). Compound 127 C16H26O6; m.p. 258.7-259.3˚C; m/z 314.2; 1H NMR (CD3OD) δ 4.53 (1H, d, J = 12.6 Hz), 4.10 (1H, dd, J = 3.8, 2.5 Hz), 3.97 (1H, dd, J = 12.0, 5.0 Hz), 3.28 (2H, dt, J = 5.0, 1.9 Hz), 3.13 (1H, d, J = 12.6 Hz), 2.38 (1H, dd, J= 12.6, 3.1 Hz), 1.99 (1H, td, J = 13.8, 4.4 Hz), 1.87 (1H, dd, J = 12.6, 5.5 Hz), 1.58 (3H, s), 1.35 (3H, s), 1.29 (3H, s), 1.00 (1H, ddd, J = 13.5, 5.1, 2.5), 0.94 (3H, s); 13 C NMR (CD3OD) δ 179.1 (C), 84.1 (C), 79.4 (C), 74.0 (CH), 73.9 (CH), 69.1 (CH), 57.1 (CH), 46.6 (C), 43.6 (CH2), 39.6 (C), 37.5 (CH2), 27.0 (CH3), 26.7 (CH2), 25.5 (CH3), 25.5 (CH3), 13.1 (CH3) Crystallographic data for 110 C16H24O5; M.W. 296.35; Orthorhombic; Space group P2(1)2(1)2(1); a = 6.0794(4) Å, b = 13.3114(8) Å, c = 18.4571(11) Å; α = β = γ = 90°; V = 1493.65(16) Å3; Z = 4; Density (calculated) = 1.318 Mg/m3; F(000) = 640; μ = 0.097 mm-1; Data were collected using a crystal size ca. 0.60 × 0.12 × 0.10 mm3. Crystallographic data for 119 C14H22O3; M.W. 238.32; Trigonal; Space group P3(2); a = 13.7631(8) Å, b = 13.7631(8) Å, c = 5.9420(7) Å; α = β =90°, γ = 120°; V = 947.76(14) Å3; Z = 3; Density (calculated) = 1.218 Mg/m3; F(000) = 390; μ = 0.084 mm-1; Data were collected using a crystal size ca. 0.46 × 0.24 × 0.20 mm3. Crystallographic data for 120 C19H28O5; M.W. 336.41; Monoclinic; Space group C2; a = 33.702(2) Å, b = 6.1084(4) Å, c = 23.6121(16) Å; α =90°, β =132.5°, γ = 90°; V = 3581.7(4) Å3; Z = 8; Density (calculated) = 1.248 Mg/m3; F(000) = 1456; μ = 0.089 mm-1; Data were collected using a crystal size ca. 0.66 × 0.28 × 0.16 mm3. Crystallographic data for 122 C20H32O5; M.W. 352.46; Orthorhombic; Space group P2(1)2(1)2(1); a = 8.7458(5) Å, b = 10.7585(6) Å, c = 20.0068(11) Å; α = β = γ = 90°; V = 1882.47(18) Å3; Z = 4; Density (calculated) = 1.244 Mg/m3; F(000) = 768; μ = 0.088 mm-1; Data were collected using a crystal size ca. 0.40 × 0.30 × 0.10 mm3. Crystallographic data for 123 C16H24O4; M.W. 280.35; Orthorhombic; Space group P2(1)2(1)2(1); a = 6.6280(12) Å, b = 13.669(2) Å, c = 16.319(3) Å; α = β = γ = 90°; V = 1478.5(4) Å3; Z = 4; Density (calculated) = 1.259 Mg/m3; F(000) = 608; μ = 0.089 mm-1; Data were collected using a crystal size ca. 0.44 × 0.20 × 0.12 mm3. Crystallographic data for 124 C16H28O6; M.W. 316.38; Orthorhombic; Space group P2(1)2(1)(1); a = 6.539(3) Å, b = 13.722(5) Å, c = 18.089(7) Å; α = β = γ = 90°; V = 1623.0(11) Å3; Z = 4; Density (calculated) = 1.295 Mg/m3; F(000) = 688; μ = 0.098 mm-1; Data were collected using a crystal size ca. 0.60 × 0.30 × 0.30 mm3. Chapter 4 Chemistry of Plagiochila colorans 4.1 Introduction Belonging to the family Plagiochilacae, plagiochila is the largest genus of the Hepaticae xliii, and it contains more than 1200 species. Most species of plagiochila have a creeping rhizome, and the rhizome strongly adheres to a substrate such as tree trunks or rock surfaces, from which erect stems arise at regular intervals or form a cluster. But in some species such as P.beddomei and P.humicola the rhizomes are absent xliv, and the shoots grow directly from the substrates. Plagiochila is widespread in all over the world, but its species are more common in warm-temperate, subtropical, tropical and oceanic regions. Plagiochila is a rich source of terpenoids and aromatic compounds. Many species of this genus such as P. stephensoniana, P. peculiaris, P. kroneana, P. hondurensis, P. dichotoma, P. gayana, P. scopulosa, etc. have been studied during the past decades, and a series of secondary metabolites such as sesquiterpenoids, diterpenoids, steroids, flavanoids, bibenzyls and bisbibenzyls have been discovered. For example, the study of P. friabilis afforded anastreptene (128), ent-spathulenol (129), β-barbatene (130), ent-bicyclogermacrene (131), campesterol (132) and squalene (133) xlv, the study of P. stephensoniana led to the discovery of 13-epi-neoverrucosan-5β-ol (134) xlvi , 3-methoxy-4’-hydroxyl bibenzyl (135) xlvii , the study of P. sciophila afforded marchantin C (136), marchantin H (137) xlviii, and the study of P. jamesonii afforded tricetin-6,8-di-C-glucoside (138) xlix. H H HO (128) anastreptene H H (129) ent-spathulenol (130) β-barbatene HO (132) campesterol (131) ent-bicyclogermacrene H HO (133) squalene (134) 13-epi-neoverrucosan-5β-ol OH O OH OCH3 OH OH (135) 3-methoxy-4’-hydroxybibenzyl (136) marchantin C OH O OH Glu HO O OH Glu OH OH O O OH OH (137) marchantin H (138) tricetin-6,8-di-C-glucoside 4.2 Results and Discussions Phytochemistry of Plagiochila species has been studied for decades, but the chemistry of P. colorans has not been investigated yet. In this project, the diethyl ether (Et2O) extracts of P. colorans were studied to afford two known sesquiterpenoids: peculiaroxide (139) and gymnomitrol (140). Peculiaroxide (139) Compound (139) was obtained as colorless solid. C15H26O; [α]D = +3.74 (c = 9.9 mg/mL, Acetone); its 1H and 13 C NMR spectra revealed that it had four tertiary methyl groups [δH 1.16 (3H, s), 1.07 (3H, s), 0.98 (3H, s), 0.82 (3H, s); δC 28.1 (C-14), 27.4 (C-12), 26.5 (C-13), 24.1 (C-11)] and one secondary methyl group [δH 0.85 (3H, d, J = 6.3 Hz); 15.0 (C-15)], In addition, it had three quaternary carbons [δC 73.9 (C-10), 69.6 (C-4), 33.0 (C-7)], and C-4 and C-10 should bond to oxygen according to their chemical shifts. Because this compound had only one oxygen atoms, C-10 and C-4 must be connected in the form of ether. Four secondary carbons and three tertiary carbons were also readily observed. From its formula, the degree of unsaturation was calculated to be 3, and there was not unsaturated bond such as alkene and carbonyl group, so this compound must contain three rings. Comparison of the NMR data with literature values showed that this compound was peculiaroxide, a drimane-type sesquiterpene ether also observed in P. peculiaris l. 11 H 15 9 3 1 O 7 5 H 12 13 14 (139) peculiaroxide Gymnomitrol (140) Compound 140 was obtained as colorless solid. C15H24O; m/z 220; [α]D = +3.85 (c = 10.9 mg/mL, Acetone); 1H and 13 C NMR spectra showed that this compound contained one secondary hydroxyl group [δH 3.72 (s); δC 91.8 (C-1)], one double bond [δH 4.65 (1H, s), 4.64 (1H, s); δC 151.3 (C-3), 108.9 (C-15)] and three tertiary methyl groups [δH 1.24 (3H, s), 1.09 (3H, s), 0.95 (3H, s); δC 28.8 (C-12), 24.7 (C-13), 19.8 (C-14)]. Its formula led to the degree of unsaturation of 140 to be 4, and because this compound had one double bond, it was concluded that it had three rings. Comparison of the NMR data with literature values revealed that this compound was gymnomitrol, a sesquiterpenoid first isolated from Gymnomitrion obtusum li and also found in Bazzania trilobata and Plagiochila trabeculata lii,liii. 15 12 H 11 3 1 OH 7 5 14 13 (134) gymnomitrol 9 4.3 Experimental Chromatography Thin Layer Chromatography (TLC) was developed on precoated glass TLC plates: normal phase TLC (Merck, Kieselgel 60F254, 250 μm), C18 silica TLC (Whatman, KC18F, 200 μm). Analytical TCL plates were visualized with UV light (254 nm) and then stained with I2 vapor. Column Chromatography (CC) was developed on silica gel (40-63 μm, Merck). For Gel Permeation Column Chromatography (GPC), Sephadex LH-20 (MeOH:CH2Cl2 = 1:1) was utilized. High Performance Liquid Chromatography (HPLC) was performed on a Shimadzu LC-8A system with RI detection or UV detection. HPLC columns: Lichrosorb 10 DIOL, 250 × 4.60 mm; Luna 5μ C18, 250 × 4.60 mm and Phenomenex partisil 10 silica, 250 × 4.60 mm. Spectroscopy Optical rotations were recorded on Perkin-Elmer 241 SCO 0937 Digital Polarimeter. Electron impact (EI) mass spectra were measured with a VG Micromass 7035 instrument. NMR spectra were measured with Bruker DPX 300 [300 MHz (1H) and 75 MHz (13C)] or Bruker AMX 500 [500 MHz (1H) and 125 MHz (13C)] using CDCl3 as solvent unless otherwise stated. Muptiplicities were determined by the DEPT pulse sequence. Coupling constants (J) were measured in Hertz (Hz). 78 g of dry Plagiochila colorans was ground and then extracted by diethyl ether (Et2O). After filtration, the ether was removed by rotary vapor to give 6.02 g of crude extract. The collected crude extract was roughly separated by gradient flash column chromatography (CC) (EtOAc:Hexane = 20:80, 30:70, 50:50, 80:20, 100:0). The collected fractions were studied by 1H NMR, and it was found terpenoids were present, thus further purification was carried out. Fraction was applied on size exclusion chromatography (Sephadex, LH20) to get rid of most of the fatty acid and chlorophyll, and two defatted fractions were collected. Further purification of the first fraction by flash CC (Acetone:Hexane = 3:97) yielded peculiaroxide (139) (9.9 mg), and the purification of the second fraction by flash CC (Acetone:Hexane = 4:96) yielded gymnomitrol (140) (10.9 mg). Peculiaroxide (139) C15H26O; [α]D = +3.74 (c = 9.9 mg/mL, Acetone); 1H NMR (CDCl3) 2.06 (1H, dddd, J = 13.2, 11.3, 4.5, 1.8 Hz), 1.60 (1H, qm, J = 9.4 Hz), 1.56 (1H, m), 1.16 (3H, s), 1.07 (3H, s), 0.98 (3H, s), 0.85 (3H, d, J = 6.3 Hz), 0.82 (3H, s); 13C NMR (CDCl3) 73.9 (C-10), 69.6 (C-4), 43.8 (C-6), 39.7 (C-8), 36.8 (C-9), 35.1 (C-5), 33.0 (C-7), 32.6 (C-1), 32.1 (C-3), 28.1 (C-14), 27.4 (C-12), 26.5 (C-13), 24.1 (C-11), 22.6 (C-2), 15.0 (C-15). Gymnomitrol (140) C15H24O; m/z 220; [α]D = +3.85 (c = 10.9 mg/mL, Acetone); 1H NMR (CDCl3) δ 4.65 (1H, s), 4.64 (1H, s), 3.72 (1H, s), 2.43 (1H, m), 2.33 (1H, s), 2.14 (1H, dd, J = 16.9, 8.1 Hz), 1.92 (1H, m), 1.81 (1H, m), 1.74 (1H, dd, J = 14.1, 8.6), 1.41 (1H, ddd, J = 13.9, 11.8, 8.2 Hz), 1.24 (3H, s), 1.09 (3H, s), 0.95 (3H, s); 13C NMR (CDCl3) δ 151.3 (C-3), 108.9 (C-15), 91.8 (C-1), 62.7 (C-2), 55.4 (C-11), 54.4 (C-7), 47.5 (C-6), 38.5 (C-10), 37.2 (C-5), 37.0 (C-8), 28.8 (C-12), 28.3 (C-4), 27.2 (C-9), 24.7 (C-13), 19.8 (C-14). Chapter 5 Biotransformation of Natural Products 5.1 Introduction Biotransformation can be generally defined to be the chemical conversion of substances by living organisms or enzyme preparations. The history of biotransformation can be traced back to hundreds of years ago, and the most common example is the production of alcohol via fermentation, and cheese via enzymatic breakdown of milk proteins. Biotransformation involves the employment of biocatalysts, which are able to greatly increase the speed of reactions. Catalysts have been frequently employed in conventional chemical synthesis, but biocatalyst utilized in biotransformation offers some unique characteristics over these conventional catalysts. First of all, biocatalysts are more powerful regarding the reaction acceleration. Typically the rates of enzyme-mediated processes are accelerated, compared to those corresponding non-enzymatic reactions, by a factor of 108-1010, and sometimes the acceleration may even exceed a value of 1012, which is far above the values that chemical catalysts are capable of achieving liv. Secondly, biocatalysts are more environmentally friendly compared with chemical catalysts. Chemical catalysts often require the use of heavy metals, and these substances always bring the problem of dispose. By contrast, biocatalysts are environmentally benign reagents since most of them could be degraded by nature. Thirdly, biocatalysts display good selectivity, and this is also the most important advantage of biocatalysts. The selectivity is often chiral (i.e. stereo-selectivity), positional (i.e. region-selectivity) and functional group specific (i.e. chemo-selectivity). One example is the hydroxylation of α-ionone (141) lv . Six Streptomyces strains such as S. fradiae Tü 27, S. arenae Tü 495, S. griseus ATCC 13273 were reported to convert α-ionone to 3-hydroxy-α-ionone (142) with high activity, and the hydroxylation of racemic α-ionone [(6R)-(-)/(6S)-(+)] led to the exclusive formation of only the two enantiomers (3R,6R)- and (3S,6S). Such high selectivity is very desirable in chemical synthesis as it may offer many benefits such as reduced or no use of protecting groups, minimized side reactions, easier separations and fewer environmental problems. More importantly, the selectivity such as stereo-selectivity often plays extremely crucial role in many fields. In the research of drug discoveries, for example, people always found that in most case only one isomer of a compound has the expected effect whist its enantiomer does not work at all or even has adverse effect, and the requirement of synthesis a compound with specific chirality is therefore more important than ever before. However, the selective synthesis is always an extremely difficult issue of researchers, and sometimes this kind of selectivity is even impossible in conventional organic synthesis. O O 1 Streptomyces strains 5 3 HO (6R)-141 (3R,6R)-142 O O 1 3 Streptomyces strains 5 HO (6S)-141 (3S,6S)-142 Scheme 5-1 Hydroxylation of α-ionone with Streptomyces strains In biotransformation the employed biocatalysts consist of two categories: isolated enzymes and whole cells. Isolated enzymes offer several benefits including simpler reaction apparatus, higher productivity due to higher catalyst concentration and simpler product purifications. Another advantage of the use of isolated enzymes is fewer steps of purification after reaction as well as better reproducibility. Comparably, the whole cell biocatalysis approach is more common when a specific biotransformation requires multiple enzymes or when it is difficult to isolate the enzyme. In addition, a whole cell system possesses an advantage over isolated enzymes in that it is not necessary to recycle the cofactors (non-protein components involved in enzyme catalysis), and it can also carry out selective synthesis using cheap and abundant raw materials lvi. Amongst various whole cell biocatalysts, microorganism is one of the most common categories amongst the various whole cell biocatalysts. The first microbial transformations of industrial importance were steroid modifications discovered in the 1950s lvii , but the systematic investigation of fungal biotransformation in drug discovery has not begun until 1970s when it was proposed that microbial systems could be utilized to mimic metabolic systems of mammals in the production of drug metabolites lviii, lix, lx . Generally, fungal biotransformation is carried out through a fermentation process, in which the substrates to be investigated is incubated with suitable fungi, and the mixture will be harvested for analysis. Fungal biotransformation has attracted considerable attention due to its good selectivity as well as relatively simple operation, and hydroxylation is one of the most common reactions. In many cases, one hydroxyl group will be introduced to the substrates via these fungal biotransformations. For example, hydroxylation of N-benzylpyrrolidines (143) with Pseudomonas oleovorans GPo1 led to the formation of (R)-N-benzyl-3-hydroxypyrrolidine (144) lxi, and the regioselective and stereoselective hydroxylation of confertifolin (145) with Mucor plumbeus ATCC 9141 resulted in 3β-hydroxyconfertifolin (146) lxii. In addition, dihydroxylation can be also achieved through fungal biotransformation. Benzoic acid (147) could be converted into produced (1S,2R)-1,2-dihydroxycyclohexa-3,5-diene-1-carboxylic acid (148) with Alcaligenes cutrophus lxiii , and naphthalene (149) could be converted into cis-(1R,2S)-1,2-dihydro-1,2-dihydroxynaphthalene (150) by Escherichia coli JM109, a recombinant strain that carries the naphthalene dioxy-genase and the corresponding regulatory genes cloned from Pseudomonas fluorescens N3 lxiv. O R COOH O N R Bn H (143) N-benzylpyrrolidines: R = H; (145) confertifolin: R = H; (147) benzoic acid (144) R = OH (146) R = OH OH HOOC OH OH OH (149) naphthalene (148) (150) So far, many fungi including the species of Aspergillus, Bacillus, Chaetosphaeria, Corynebacterium, Cunninghamella, Mucor, Penicillin, Pseudomonas, Rhizopus and so on have been reported to be able to transform natural products, and Aspergillus niger and Mucor plumbeus are two of the most common species that have been studied. For example, sesquiterpenoid (-)-maalioxide (151) from the liverwort Plagiochila sciophila was biotransformed by A. niger to afford compounds 152, 153 and 154 lxv, whilst the products were 152, 155 and 156 when the substrate was incubated with M. plumbeus lxvi. R1 (151) (-)-maalioxide: R1=R2=R3=R4=H; R2 (152) R1=OH, R2=R3=R4=H; (153) R1=R2=OH, R3=R4=H; R3 (154) R1= OH, R2=R3=H; R4=OH (155) R1=R2= H, R3=OH, R4=H; O (156) R1=H, R2=OH, R3=R4=H R4 (+)-Camphor (157) was isolated from the camphor tree, Cinnamomum camphora, and was used commercially as a moth repellent, and as a preservative in pharmaceuticals and cosmetics lxvii . Many reports on the metabolism of 157 in mammals lxviii,lxix, insects lxx, plant cell cultures lxxi and microorganisms lxxii,lxxiii have been published. For example, biotransformation of camphor in the larvae of common cutworm, Spodoptera litura, was investigated, and it showed that (+)-camphor was transformed into (+)-5-endo-hydroxycamphor (158), (+)-5-exo-hydroxycamphor (159) and (+)-8-hydroxycamphor (160), whilst the biotransformation of (-)-camphor led to the corresponding (-)-158, (-)-159 and (-)-160 (Scheme 5-2). The biotransformation with cultured cells of Eucalyptus perriniana afforded six products 161-167, all of which were suggested to form through the glucosylation of five mono-hydroxylated camphor derivatives 159, 160, 168, 169 and 170. 8 9 7 R 10 O S.litura 1 O O + + 3 O R 5 OH (+)-camphor (157) (+)-158 (+)-159: R=OH (+)-160: R=OH 8 9 7 HO 10 1 O O S.litura O + HO 5 O + 3 OH (-)-camphor (157) (-)-158 (-)-159 (-)-160 Scheme 5-2 Possible metabolic pathway of camphor (157) in the larva of S. litura O-Glc O O O-Glc 161 162 O O O R R R 163: R=O-Glc 164: R=O-Glc 165: R=O-Glc 168: R=OH 169: R=OH 170: R=OH O O O-Glc O-Glc 166 167 5.2 Results and Discussion 5.2.1. Small-scale Screening Experiments Small-scale screening experiment is a fast method employed to find out the biocatalyst that is able to transform some specific substrates to be investigated. In addition, the reaction condition such as the reaction temperature, medium, reaction time, etc. could be optimized through tracing the reaction during this trial experiment. This technique has attracted plenty of attention due to its easy and rapid operation. For example, in the biotransformation from N-benzylpyrrolidine (143) to 144 as stated above, twelve out of seventy microorganisms were determined to be active for this biotransformation within 24 hours, and it also suggested two most efficient microorganisms8. The biotransformation of camphor was carried out in small-scale at first. (±)-camphor was incubated with A. niger and M. plumbeus in liquid medium, and the mixtures were harvested after one week. The collected mixtures were filtered and extracted using ethyl acetate (EtOAc). TLC, NMR and GC were employed to analyze the collected biotransformation extracts, but GC was used as the main technique because the abundant fat produced in the biotransformation masked the expected products to much extent, which made it difficult to determine the products from TLC or NMR. GC spectra of the collected crude extracts as well as that of the parallel control experiment were shown in Table 5-1. Table 5-1 GC Data of the Small Scale Trial Experiments 1 2 3 4 5 A 6.30/6.2 11.4/7.1 11.7/9.9 12.1/9.1 12.7/6.3 B 6.26/9.6 11.0/7.6 11.5/2.5 12.2/1.3 13.1/1.8 C 16.8/6.5 20.6/7.0 21.7/16.4 22.0/10.7 22.7/4.4 D 6.5 E 6 7 8 24.6-28.1/36 33.3-34.1/5.4 24.4/6.1 27.8-28.3/35.1 33.2-26.4/6.3 23.0/2.2 27.5-28.3/25.4 33.2-34.1/1.7 33.2-34.6 A: Biotransformation of Camphor by A. niger; B: Biotransformation of Camphor by M. plumbeus; C: Control experiment with only camphor as substrate; D: Control experiment with only A. niger; Value before slash: Retention Time (in mins) of the signals; E: Biotransformation of Longiborneol by A. niger as reference; Value after slash: Relative amplitude of the corresponding signals. For the biotransformation of camphor by A. niger and M. plumbeus, from the Table 5-1, first of all, it is obviously that in both cases part of the starting materials were recovered. In addition, when no substrates were introduced to the cell culture, the fungus itself can also excrete some products (around 33 mins) as shown in the control experiment E. At the same time, when only substrates were added into the liquid medium, it seems no reaction has taken place. When substrates were added, aside from these signals, it could be noticed that some other products were generated (around 24 to 28 mins), and from their relative content (around 36%), they should be the main constituent of the mixture obtained from the biotransformation. However, these substances were unlikely to produce from the added substrate, because they were still present when the substrate was changed into longiborneol as shown in C. From the data of that row, it could be observed that the biotransformation of longiborneol by A. niger generated also some signals at 33 mins and 24-28 mins. If these substances were directly related to the substrates, different substrates should lead to different products. As a result, the only reasonable conclusion is that these substances were generated from biotransformation, but may be from the microorganism. In terms of the biotransformation of camphor, it could be seen that in addition to the starting materials (6.5 min) and the two kinds of products described above (24-28 min, 33 min), the use of both A. niger and M. plumbeus afforded approximate four signals in the region of 11 mins to 13 mins, but the relative content was definitely not identical. These results clearly showed that both of these two fungi were able to transform camphor. 5.2.2. Biotransformation of (±)-Camphor by Mucor plumbeus The substrate (±)-camphor was incubated with M.plumbeus for seven days. The MeOH extract of the mycelium was combined with the EtOAc extract of the broth. Isolation of the total extracts by chromatography led to the discoveries of three hydroxylation products, 5-endo-hydroxycamphor (158), 5-exo-hydroxycamphor (159), and 6-endo-hydroxycamphor (168) (Scheme 5-2) O O O M.plumbeus O + + OH OH OH camphor (157) (158) (159) (168) Scheme 5-3 Scheme of the biotransformation of camphor with M. plumbeus 5-exo-hydroxycamphor (159) Compound 159 was obtained as colorless oil. The 1H and 13 C NMR spectra indicated the presence of one ketone carbonyl group [δC 218.2 (C-2)], three methyl groups [δH 1.25 (s), 0.93 (s), 0.85 (s); δC 21.0 (C-9), 20.1 (C-8), 8.9 (C-10)], two secondary carbons [δC 40.4 (C-6), 40.0 (C-3)], two tertiary carbons [δH 4.02 (dd, J = 7.6, 3.8 Hz), 2.15 (d, J = 6.3 Hz); δC 74.6 (C-5), 50.9 (C-4)] and two quaternary carbons [58.7 (C-1), 46.5 (C-7)]. Compared with the starting material, camphor, the most significant difference was the doublet-doublet at 4.02 (J = 7.6, 3.8 Hz), which revealed that one hydroxyl group was introduced at C-5. The tertiary carbon peak at 74.6 ppm as shown in the 13 C spectrum also supported this deduction. Careful comparison of the NMR data with literature values showed that this compound was 5-exo-hydroxycamphor17. 6-endo-hydroxycamphor (168) and 5-endo-hydroxycamphor (158) These two compounds were collected as a mixture, and their presence was revealed by NMR data, from which it could be observed that the amounts of these two compounds were approximately 1:3.5 based on the integration. 6-endo-hydroxycamphor (168) was the major compound. Three methyl groups were present [δH 0.84 (s, 3H), 0.98 (s, 6H); δC 20.7 (C-8), 19.8 (C-9), 7.3 (C-10)]. In addition, a secondary alcohol was observed [δH 4.18 (ddd, J= 9.4, 2.5, 1.2 Hz); δC 75.6 (C-6)], and the coupling constant indicated that this CH group was next to a CH2 group, and at the same time, the tertiary proton was also coupled to another proton through a long-range coupling (J=1.2 Hz). Therefore, this hydroxyl group must be at C-6. Comparison of the NMR data with literature values revealed that this compound was 6-endo-hydroxycamphor lxxiv,lxxv. For the other compound (158) in this fraction, the three methyl groups of camphor were still existing [δH 1.01 (s, 3H), 0.87 (s, 3H), 0.86 (s, 3H); δC 20.3(C-9), 19.3(C-8), 9.3(C-10)]. A secondary alcohol was also observed [δH 4.63 (dddd, J = 9.4, 3.8, 3.8, 1.3 Hz); δC 69.6 (C-6)], and the coupling constant implied that this CH group should be next to a CH2 group and another CH group, and at the same time, it was also coupled by a proton through long-range coupling (J = 1.3 Hz). In this case, the introduced OH group must be at the position of C-5. Comparison of the NMR data showed that this compound was 5-endo-hydroxycamphor17. 5.2.3. Biotransformation of (±)-Camphor by Aspergillus niger The substrate (±)-camphor was incubated with A. niger for seven days. The MeOH extract of the mycelium was combined with the EtOAc extract of the broth. Isolation of the total extracts by chromatography led to the discoveries of three hydroxylation products, 5-endo-hydroxycamphor (158), 5-exo-hydroxycamphor (159), 6-endo-hydroxycamphor (168) and 6-exo-hydroxycamphor (170) (Scheme 5-3). O O M.plumbeus 158 (157) camphor + 159 + 168 + OH (170) Scheme 5-4 Scheme of the biotransformation of camphor with A. nigers 5-exo-hydroxycamphor (159) was obtained as colorless solid, and its 1H and 13C NMR data was identical to that obtained from the biotransformation of camphor with M. plumbeus as described above. In another fraction, 5-endo-hydroxycamphor (158) and 6-endo-hydroxycamphor (168) were collected as a mixture again, and its NMR data was the identical to that from the biotransformation by M. plumbeus as well. 6-exo-hydroxycamphor (170) This compound was obtained with some impurities, but its structure could be determined by its NMR data. The similarity of the 1H and 13C NMR spectra revealed that this biotransformation product was also a monohydroxylated camphor derivative. The characteristic resonance at 3.75 ppm (dd, J = 7.5, 4.4 Hz) indicated that this proton was next to a hydroxyl group and a methylene group. Hence, the introduced hydroxyl group must be at the position of C-6. In addition, three methyl groups could be recognized from the resonances at 1.18 ppm, 0.96 ppm and 0.82 ppm. Comparison of the 1 H NMR data with reference revealed that this compound was 6-exo-hydroxycamphor (170) lxxvi. . 5.3 Experimental 5.3.1 General Procedure for Biotransformation A. niger and M. plumbeus were obtained from United Kingdom National Culture Collection (UKNCC). Fresh mycelium was obtained from cell culture of the fungi to be used before every biotransformation was carried out, and in the cell culture process, fungi spores were grown in potato dextrose agar (PDA) medium. A typical biotransformation consist two steps. First of all, small scale trial experiments were developed to screen the fungi that were capable to transform the substrate to be studied. Next, the selected biotransformation was carried out in regular scale to find out the products from this biotransformation. In small scale screening experiments, the general procedure as shown below was followed: 1. Cultivate M. plumbeus and A. niger, the fungi to be investigated, on PDA medium; 2. Collect the sporulated fungi and transfer them into three 250-mL conical flasks which are filled with 100 mL liquid medium each. The constituent of the medium employed was (per liter): glucose (30 g), potassium dihydrogen phosphate (2 g), magnesium sulfate (2 g), ammonium tartrate (2 g), yeast extract (1 g), calcium chloride (0.1 g), ferrous ammonium sulfate (0.1 g) and a trace elements solution (2 mL). The composition of trace elements solution is (per liter): zinc sulfate (1 g), ferrous sulfate (1 g), cobalt nitrate (1 g), ammonium molybdate (1 g), copper sulfate (0/1 g) and manganese sulfate (0.1 g). 3. Place the conical flasks on incubate shaker (150 rpm) at 25oC, and the substrate to be studied are introduced into two of the three conical flasks after 24 hours, and the rest one containing no substrate is set as control experiment. 4. Continue to place the conical flasks on shaker to let the fermentation take place. 5. 5 mL of fermentation mixtures is sampled from each conical flask every two days. The collected samples are filtered and then extracted by EtOAc. 6. The extracts of both biotransformation and control experiment are analyzed by TLC, GC-FID, GC-MS and NMR at first, and the results will be compared with that of the substrates and the control experiment. If the transformation process produces new signals compared with the other two samples (substrate and control products), it implies that the investigated fungi may be able to transform the substrate, and in this case, the biotransformation will be extended to regular scale. For the regular scale biotransformation, all the medium and reaction conditions are kept identical to those employed in screening experiment unless otherwise stated. Sporulated fungi are transferred into twenty 250-mL conical flasks which are filled with 100 mL of liquid medium each. After shaking for 24 hours, substrate that is dissolved in EtOH is equally distributed into these conical flasks, and they are continued to place on shaker. The fermentation mixture is harvested on the seventh day, and filtration, extraction and further analysis will be carried out. 5.3.2 Biotransformation of (±)-Camphor by M. plumbeus Fresh sporulated M. plumbeus was transferred into three 250-mL conical flasks that were filled with 100 mL of liquid medium each. Then place the flasks on shaker at 25oC. After 24 hours, 30 mg of camphor that was dissolved in 0.8 mL of EtOH was evenly distributed in two conical flasks, and the rest one was kept as control experiment. Sampling was carried out every two days as described in the general procedure. The fermentation mixture was harvested after one week, and they were filtered at first. Next, the collected liquid phase was extracted by EtOAc, and then dried on vacuum rotary vapor. TLC, GC-MS and NMR were employed to analyze the collected extracts. It was found that M. plumbeus was able to transform camphor, so the biotransformation was carried out in larger scale. Sporulated M. plumbeus was inoculated in five 250-mL of camphor that were filled with 100 mL of liquid medium each on shaker. 75 mg of camphor that was dissolved in 2 mL of absolute EtOH was equally distributed into these five flasks after 24 hours, and the culture was still kept on shaker for another seven days. Fermentation mixture was harvested, filtered and the obtained liquid phase was extracted by ethyl acetate (EtOAc). After drying on reduced pressure evaporation, 85.0 mg of crude extracts was obtained. The biotransformation crude extracts were roughly separated by gradient flash column chromatography (EtOAc: Hexane = 5:95, 30:70, 50:50, 60:40, 100:0) to afford seven fractions. The first five fractions were mainly fat based on their 1H NMR data, so they were not further studied. The sixth fraction Fr. 6 (11.0 mg) was further separated by HPLC (DIOL, EtOAc: Hexane = 30:70) to yield two sub-fractions: Fr. 61 (0.9 mg) and Fr. 62 (1.2 mg). The 1 H NMR spectra showed that Fr. 61 was 5-exo-hydroxycamphor (159), whilst fraction Fr. 62 was the mixture of 5-endo-hydroxycamphor (158) and 6-endo-hydroxycamphor (168). The intensity of the 1H NMR spectrum of this fraction revealed that the content of these two compounds were approximately 1:3. 5.3.3 Biotransformation of (±)-Camphor by A. niger Compared with the biotransformation of camphor by M. plumbeus, the only difference for the biotransformation of camphor by A. niger was that M. plumbeus was replaced by A. niger whilst all other operations kept identical. The screening experiment indicated that A. niger was able to transform camphor. Therefore, the biotransformation was carried out in larger scale. Fresh sporulated A. niger was transferred into twenty 250-mL conical flasks, each of which was filled with 100 mL of liquid medium. 380 mg of camphor that was dissolved in 8 mL of absolute ethanol was equally distributed into these twenty conical flasks after 24 hours, and the cultivation was continued on shaker at 25oC. The fermentation mixture was harvested and filtered. The collected liquid phase was extracted by ethyl acetate (EtOAc) through liquid-liquid extraction to give 365 mg of crude extract Fr. A. Meanwhile, the mycelium was firstly extracted by methanol (MeOH) through liquid-solid extraction. After filtration, the collected liquid part was also extracted by EtOAc through liquid-liquid extraction to yield 442 mg of crude extract: Fr. B. 1H NMR spectra of these two crude extracts showed that extract BCA-1 was mainly biotransformation product as well as some un-reacted camphor, whilst extract Fr. B contained mainly fat, but some products were readily observed. Crude extract Fr. A was roughly separated by gradient flash column chromatography (EtOAc: Hexane = 30:70, 40:60, 50:50, 100:0) to yield four fractions. The first fraction Fr. 1 (36.6 mg) was mainly recovered camphor (138) according to its 1H NMR spectrum. The last two fractions Fr. 4 (5.3 mg) and Fr. 5 (106.5 mg) contained some aromatic compounds and other substances that were believed to produced by the fungi itself, so they were not further studied. The second fraction Fr. 2 (31.5 mg) and Fr. 3 (34.1 mg) contained the biotransformation products and was further separated. Further separation of Fr. 2 by HPLC (DIOL, EtOAc:Hexane = 30:70) afforded 6-endo-hydroxycamphor (168) (10.1 mg), and the further separation of Fr. 3 by HPLC (DIOL, EtOAc:Hexane = 30:70) afforded 5-exo-hydroxycamphor (159) (3.8 mg), 6-exo-hydroxycamphor (170) (3.0 mg) and the mixture of 5-endo-hydroxycamphor (158) and 6-endo-hydroxycamphor (168). 5-endo-hydroxycamphor (158) Colorless solid; C10H16O2; 1H NMR (CDCl3) δ 4.63 (1H, dddd, J = 9.4, 3.8, 3.8, 1.3 Hz, H-5exo), 2.71 (1H, d, J =18.3 Hz, H-3endo), 2.17 – 2.22 (3H, m, H-3exo, H-4 and H-6exo), 1.26 (1H, dd, J=14.5, 3.8 Hz, H-6endo), 1.00 (3H, s, H-8), 0.87 (3H, s, H-10), 0.86 (3H, s H-9); 13C NMR (CDCl3) δ 218.3 (C-2), 69.6(C-5), 59.1(C-1), 48.8(C-4), 47.6(C-7), 41.0(C-6), 34.6(C-3), 20.3(C-9), 19.3(C-8), 9.3(C-10) 5-exo-hydroxycamphor (159) Colorless solid; C10H16O2; 1H NMR (CDCl3) δ 4.02 (1H, dd, J = 7.6, 3.8 Hz, H-5endo), 2.34 (1H, dd, J = 18.3, 5.1 Hz, H-3exo), 2.15 (1H, d, J = 6.3 Hz, H-4), 1.86 (1H, dd, J = 14.5, 7.5 Hz, H-6endo), 1.80 (1H, dd, J = 15.1, 3.8 Hz, H-6exo), 1.68 (1H, d, J = 18.3 Hz, H-3endo), 1.25 (3H, s, H-8), 0.93 (3H, s, H-10), 0.85 (3H, s, H-9); 13C NMR (CDCl3) δ 218.2 (C-2), 74.6 (C-5), 58.7 (C-1), 50.9 (C-4), 46.5 (C-7), 40.4 (C-6), 40.0 (C-3), 21.0 (C-9), 20.1 (C-8), 8.9 (C-10). 6-endo-hydroxycamphor (168) Colorless solid; C10H16O2; 1H NMR (CDCl3) δ 4.18 (1H, ddd, J = 9.4, 2.5, 1.2 Hz, H-6exo), 2.56 (1H, dddd, J = 17.5, 7.5, 4.4, 1.9 Hz), 2.45 (1H, ddd, J = 18.3, 4.4, 4.4 Hz), 2.15 (1H, m), 2.01 (1H, d, J = 18.3 Hz), 1.34 (1H, dd, J = 13.2, 2.5 Hz), 0.98 (6H, s), 0.84 (3H, s); 13C NMR (CDCl3) δ 216.5 (C-2), 75.9 (C-6), 63.8 (C-1), 48.7 (C-7), 43.5 (C-4), 41.6 (C-3), 37.7 (C-5), 20.7* (C-8), 19.8* (C-9), 7.3 (C-10). 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Biotransformation. 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OH OH COOH (67) jacareubin (68) scriblitifolic acid There have been extensive studies of the chemistry of the genus Calophyllum, and natural products from C wallichianum will be introduced in this chapter 2.2 Results and Discussions Phytochemical studies of the hexane extract of C wallichianum led to the isolation of seven known compounds, cordatolide A (63), cordatolide B (64), 12-O-methylcordatolide... (52) lobeline (53) byrostatin-1 H Chapter 2 Chemistry of Calophyllum wallichianum 2.1 Introduction Calophyllum is a plant genus of tropical evergreen trees in the family Clusiaceae with approximately 200 species The distribution of this genus of trees is rather wide, and they are found in Madagascar, eastern Africa, South and Southeast Asia, the Pacific islands, and the West Indies as well as South America... doublet splitting patterns Despite of the high similarity of the NMR spectrum between compound 75 and 72, their difference of the resonances of H-6, H-7 and H-8 was also clear Compare with the 2.5 Hz of JH-6,7 and 5.9 Hz of JH-7,8 for 72, the coupling constants both became to 1.9 Hz for 75 Although it was still insufficient to establish the relative stereochemistry of this compound from the coupling... are a huge number of natural products in nature, and they differ greatly in terms of their structures, characteristics and functions in living creatures However, NH2 the number of building blocks required to biosynthesize these metabolites are surprisingly few Acetate pathways, shikimate pathways, mevalonate pathways and deoxyxylulose phosphate pathways cover the biosynthesis of most of the secondary... 2-3: ORTEP diagram of compound 75 75 To establish its stereochemistry, crystallization of compound 69 was carried out and the following X-ray analysis led to the diagram as shown in Fig 2-3, and the structure of this compound therefore was established It could be observed that the structure was almost identical to pseudocordatolide C (72) except the stereochemistry of C-6, C-7 and C-8, and this structure.. .and secondary metabolites is sometimes blurred For example, some fatty acids and sugars are extremely rare and found only in several species, and at the same time, some sterols are found to play essential role for the survival of many organism and therefore must be considered to be primary metabolites Currently, the concept of natural products is widely considered to... elucidation even with trace quantity iv Natural products do not directly relate to the survival of creatures, their crucial roles in the evolutionary and ecological perspectives, however, have been widely recognized for a long time In plant kingdom, some natural products serve as attractants to ensure pollination and reproduction, some act to warn and defend against herbivores and some other compounds play significant ... 1.2 Natural Products 1.3 Biosynthesis of Natural Products 1.4 Natural Products in Modern Drug Discovery Chapter Chemistry of Calophyllum wallichianum 12 14 2.1 Introduction 14 2.2 Results and. .. general background of natural products chemistry Chapter two to chapter four concern the chemical studies of three plants: Calophyllum wallichianum, Scapania undulata and Plagiochila colorans The last... Calophyllum wallichianum, Scapania undulata, Plagiochila colorans, Biotransformation List of Tables Table 2-1 1H, 13C NMR Data and HMBC Correlations of 74 Table 3-1 1H, 13C NMR Data of 117 and 1H