... silica gel using hex-
ane-EtOAc, mixtures of increasing polarity consisting of four kaurenoid carboxylic acids:
(–)-kaur-16-en-19-oic acid (28), (–)-grandifloric acid, (–)-angeloylgrandifloric ... of poten-
tial natural herbicides.
In this chapter we present a selection of plant terpenoids belonging to natural and agro-
ecosystems, from monoterpenes to triterpenes and steroids, with poten...
... plants confirmed its association with L-3,4-dihy-
droxyphenylalanine (L-DOPA). It is well known that velvetbean seeds contain a high con-
centration of L-DOPA (6 to 9%),
20,21
which plays a role ... and/or weed-control crop. This chapter reviews the
results of studies on allelopathic activities of Mucuna pruriens with special emphasis on
L-DOPA as a potential allelochemical with weed-suppre...
... derivatized to yield the herbicides dicamba (3,6-dichloro-
2-methoxybenzoic acid) and chloramben (3-amino-2,5-dichlorobenzoic acid). The allelo-
pathic terpenoid 1,8-cineole has served as a model for the ... released.
1 4-1 6
5.2 Tree-of-Heaven (Ailanthus altissima)
Tree-of-heaven (Ailanthus altissima, Simaroubaceae) has been known since the work of Mer-
gen in 1959 to produce one or more p...
... natural compounds:
(24R )-1 4α-methyl-5α-ergostan-3-one; 14α-methyl-5α-cholestan-3-one; cycloart-5-ene-
3β,25-diol; cycloart-3β,25-diol; 4α-methylergostan-5-ene-3β-ol; stigmast-4 ,2 2- dien-6β-ol- 3-
one ... stigmast-4 ,2 2- dien-6β-ol- 3-
one and 24-phenylethyl-cholest-3,6-dione were identified; together with several known
compounds: (24R)-stigmast-4-ene-3-one; ergost-4-ene-3-one; (...
... aromatic amino acids), not naturally occurring JA-Gly, JA-β-Ala, JA-ACC,
JA-(+)-coronamic acid were also synthesized. Among them, JA-Leu, JA-Ile, JA-Val,
JA-ACC, and JA-(+)-coronamic acid are structurally ... ana-
logs [(± )-1 9b, -1 9c, -1 9d, -2 0a, -2 0b, -2 0c, and -2 0d] of 2, could be synthesized from (± )-1 8a-d
(Scheme 8.4).
22
In principle, this method would b...
... analog,
L-(N
5
-phosphono)methionine-S-sulfoximine (PMSO) (see Figure 9.8) is a potent GS inhibi-
tor and a metabolite of L-(N
5
-phosphono)methionine-S-sulfoximinyl-L-ala-L-ala (PMSO-
Ala-Ala)
76
... herbicides (pendimetha-
lin [N-(1-ethylpropyl )-3 ,4-dimethyl-2,6-dinitrobenzenamine]; thiobencarb [S-[(4-chlorophe-
nyl)methyl]-diethylcarbamothioate]; quinclorac (3,7-dichloro-8-quinolineca...
... most lucrative sources of phytotoxic allelochemi-
cals. Plant-derived phytotoxins have been the sources of two commercial herbicides: a 1, 8-
cineole-derived herbicide, cinmethylin,
49
and the newly ... tissue of Artemisia annua support this view. Leaf tissues (stems
excluded), were cut from 8-week-old potted plants and weighed. A half portion of the fresh
plant material was extracted by...