58 Cyclopropene Fatty Acid and Amide: Inhibitors of the Pheromone Biosynthesis in Bombyx mori.
11,12-Methylenehexadec-11-enoic acid and the amide were synthesized by the method of Baird
et al. (1992)
via a key intermediate, 1,2,2-tribromo-l-butylcyclopropane, which was debrominated and coupled with an alkylhalide resulting in a dialkylcyclopropene. Their activities as inhibitors of pheromone biosynthesis were examined with virgin females of the silkworm moth,
Bombyx mori,
in vivo. Bombykol titer diminished in the pheromone glands treated with the cyclopropenes, and experiments utilizing [1-
14C] or [16,16,16-
2H
3]hexadecanoic acids as a biosynthetic precursor showed that the cyclopropenes completely inhibited incorporation of the isotopes into bombykol and (
Z)-11-hexadecen-l-ol at the dose of 1μg per pheromone gland but accelerated incorporation into hexadecan-l-ol. These results revealed the acid and amide with a propene ring at the 11-position are inhibitors of desaturation step(s), Δ11-desaturation and possibly Δ10,12-desaturation, in the biosynthetic pathway. The nitrile derivative with the propene ring did not inhibit the bombykol biosynthesis.
59 Sex Attractants of Geometrid and Noctuid Moths: Chemical Characterization and Field Test of Monoepoxides of 6,9-Dienes and Related Compounds.
(
Z,Z)-6,9-Dienes with straight C
18-C
23 chains were synthesized from linoleic acid, and a C
17 chain was synthesized by hydrogenation of the corresponding 6,9-diyne prepared from propargyl alcohol. Oxidation of the homoconjugated dienes with
m-chloroperoxybenzoic acid yielded a 1:1 mixture of two monoepoxides that could be separated by repeated medium-pressure liquid chromatography with a Lobar column. The chemical structure of each positional isomer was confirmed by analyses of the ozonolysis products, and the isomers showed characteristic
13C signals in their NMR spectra and fragment ions in their El mass spectra. In addition to the (
Z,Z,Z)-3,6,9-trienes with straight C
17-C
23 chains and their monoepoxides, field tests using single source lures incorporating one of the above seven dienes and 14 monoepoxymonoenes were carried out in a forest in Tokyo from 1992 to 1994. Consequently, attraction of six geometrid species and five noctuid species was observed for the first time.
60 Identification of Female Sex Pheromone Components of Rice Looper, Plusia festucae (L.), (Lepidoptera: Noctuidae).
The rice looper,
Plusia festucae, is a defoliator of the rice plant. Chromatographic behavior, chemical reactions, and GC-MS analyses of the female sex pheromone revealed that the main component was (
Z)-5-dodecenyl acetate (Z5-12:OAc. component I). The GC-MS analysis also indicated that the pheromone gland extract included another three monounsaturated components, (
Z)-5-dodecen-l-ol (Z5-12:OH, component II), (
Z)-7-tetradecenyl acetate (Z7-14:OAc, component Ill), and (
Z)-7-tetradecen-1-ol (Z7-14:OH, component IV) in the following ratio: 1 : II :lIl : IV = 100 : 6 : 15 : 1. In a paddy field, the mixture of synthetic I, II, and III in a ratio of 100 : 6 : 15 showed stronger attractancy than the virgin female, while the role of IV was unknown.
61 Sex Pheromone of the Sweetpotato Hornworm, Agrius convolvuli (L.) (Lepidoptera: Sphingidae): Identification of a Major Component and Its Activity in a Wind Tunnel.
A major EAG-active components was identified as (
E,E)-11,13-hexadecadienal (E11,E13-16:Ald) in extracts from the abdominal tips of female moths of the sweetpotato hornworm,
Agrius convolvuli (L.) (ca. 7 ng/female). Synthetic E11,E13-16:Ald showed a potent attractant activity to males in a wind tunnel.
62 Termination of Sex Pheromone Production in Mated Females of the Silkworm Moth.
A mating duration of more than 6 h was necessary to permanently terminate the production of the sex pheromone (bombykol) in the silkworm moth,
Bombyx mori L. (Lepidoptera: Bombycidae), although the female formed a bursa copulatrix including a spermatophore and laid fertilized eggs even after mating for only 0.5 h. The 6-h mated female again produced bombykol if given an injection of synthetic pheromonotropic neuropeptide (PBAN), which is known to activate pheromone biosynthesis in a virgin female. Extracts of brain-suboesophageal ganglion (SG) complexes, which were removed from 6- and 24-h mated females, showed strong pheromonotropic activities. These results indicated that the pheromone gland of the mated female maintained its ability to biosynthesize bombykol; however, it could not produce pheromone due to a suppression of PBAN secretion from the SG. Furthermore, bombykol titers did not decrease after mating in females with a transected ventral nerve cord, even after the injection of a spermatophore extract, suggesting that the suppression of PBAN secretion was mediated by a neural signal and not by a substance in the spermatophore. The mated females accumulated (10
E,12
Z)-10,12-hexadecadienoic acid, a precursor of bombykol biosynthesis, in their pheromone glands as did decapitated females.
63 Structure-activity Relationships of Cyclopropene Compounds, Inhibitors of Pheromone Biosynthesis in Bombyx mori.
According to the synthetic route for 11,12-methylenehexadec-11-enoic acid [10-(2-butyl-1-cyclopropenyl)decanoic acid] and the amide, their related cyclopropene compounds, which possessed a propene ring at the 7,8-, 9,10-, or 13,14-position in a C
16 chain and the 11,12-position in a C
14 or C
18 chain, were synthesized via the corresponding 1-alkyl-1,2,2-tribromocyclopropane. Their activities as biosynthetic inhibitors of bombykol [(10
E,12
Z)-10,12-hexadecadien-1-ol; sex pheromone of the silkworm moth
Bombyx mori L.] were measured with virgin female silkworm moths
in vivo. The 7,8-methylene compounds were inactive even at the dose of 10 μg/gland, but other compounds at 1 μg/gland inhibited the conversion of [16,16,16-
2H
3]hexadecanoic acid to bombykol to some extent. Each amide showed stronger inhibitory activity than the corresponding acid, and the 11,12-methylene amide with a C
16 chain was the strongest (I
50 = 0.016 μg/gland) among the tested compounds. Furthermore, experiments comparing the incorporation of [1-
14C]hexadecanoic acid into bombykol and another alcohol component in the pheromone gland, (
Z)-11-hexadecen-1-ol, suggested that the Δ11-desaturation was blocked by 9,10- and 11,12-methylene compounds and the subsequent Δ10,12-desaturation by 11,12- and 13,14-methylene compounds.
64 Resolution of Pheromonal Epoxydienes by Chiral HPLC, Stereochemistry of the Separated Enantiomers and Their Field Evaluation.
Resolution of insect pheromonal
cis-epoxydiene racemates derived from (
Z,Z,Z)-3,6,9-trienes with a C
18-C
23 chain was examined utilizing chiral HPLC columns, and the result showed that a Chiralpak AS column was suitable to separate enantiomers of the 3,4-epoxides, and a Chiralpak AD column was indispensable for the resolution of the racemic 6,7- and 9,10 epoxides. The absolute configuration of the enantiomers of the 3,4- and 9,10epoxides separated by HPLC was studied after methanolysis of their epoxy rings. Examination of the
1H NMR data from esters of the methoxyalcohols produced by a modified Mosher's method with (
S)- and (
R)-
α-methoxy-
α-(trifluoromethyl)phenylacetic acid indicated that the dextrorotatory parent epoxides with a shorter
Rt were 3
S,4
R and 9
S,10
R isomers and the levorotatory enantiomers having a longer
Rt possessed 3
R,4
S and 9
R,10
S configuration. Field tests with both enantiomers of (
Z,Z)-6,9-
cis-3,4-epoxynonadecadiene separated by HPLC with the chiral column revealed new specific attraction of geometrid forest defoliators,
Pachyerannis obliquaria, to the 3
R,4
S isomer and
Zetnenia albonotaria nesiotis to the 3
S,4
R isomer.
65 Sex Pheromone of Japanese Giant Looper, Ascotis selenaria cretacea: Identification and Field Tests.
The Japanese giant looper,
Ascotis selenaria cretacea, is a serious defoliator of tea gardens in Japan. GC-MS analysis of the virgin female extract confirmed the presence of (
Z,Z)-6,9-
cis-3,4-epoxynonadecadiene. This compound had attracted male moths in a previous random screening test using C
17-C
23 epoxydienes synthesized in a racemic form. Further GC and HPLC analyses with chiral columns showed that the natural pheromone was composed of 3
S,4
R and 3
R,4
S isomers in a ratio of 53:47, although the field evaluation revealed stronger activity of the pure 3
R,4
S epoxide than of other enantiomeric mixtures. This result indicates that the sexual communication system of this Japanese subspecies differs from that of the species in Israel, which is selectively attracted to an isomer with the opposite configuration. Interestingly, the 3
S,4
R epoxide attracted another geometric male,
Alcis angulifera, in our field tests. (
Z,Z,Z)-3,6-9-Nonadecatriene, a parent olefinic compound of the epoxy pheromone, was also identified in the gland extract of
A. s. cretacea, but its effect on the attractive activity of the epoxide was not assured in field tests. The amount of the triene increased in the virgin female during photophase and also after decapitation. The epoxy component completely disappeared after decapitation, but could be increased by an injection of subesophageal ganglion extract. The data suggest that the triene is a biosynthetic precursor of the epoxide and that a neuropeptide hormone (PBAN) regulates the epoxidation.
66 Stereochemistry of Δ11-Desaturation and Inhibitors of Δ10,12-Desaturation in the Biosynthesis of Bombykol, Sex Pheromone of the Female Silkworm Moth, Examined with Deuterated Precursors.
Bombykol [(10
E,12
Z)-10,12-hexadecadien-1-ol], the sex pheromone of the silkworm moth (
Bombyx mori L.), is biosynthesized from hexadecanoate by three successive steps;
i.e., Δ11-desaturation, Δ10,12-desaturation, and reduction of the acyl group. 11,12-
Erythro- and 11,12-
threo-[7,8,11,12-D
4]hexadecanoic acid (D
4-16:Acid) were synthesized
via the catalytic hydrogenation of the corresponding 7,11-diene compounds with a Wilkinson’s catalyst under deuterium gas and applied to the pheromone gland of
B. mori. GC-MS analysis of their conversion into bombykol and (
Z)-11-hexadecen-1-ol, another component in the pheromone gland, revealed that the Δ11-desaturation proceeded in
syn-elimination. A previous experiment using [16,16,16-D
3]16:Acid has shown that some cyclopropene fatty acids and the amides inhibit the desaturation steps of bombykol biosynthesis. In order to define the structure-activity relationships, [13,13,14,14,15,15,16,16,16-D
9](
Z)-11-hexadecenoic acid (D
9-Z11-16:Acid) was synthesized from D
10-1-butanol; and the effect of cyclopropene compounds on the incorporation of D
9-Z11-16:Acid into bombykol was examined utilizing a selected ion monitoring technique of GC-MS. The result confirmed that Δ10,12-desaturation was strongly inhibited by 11,12-methylenehexadec-11-enoic acid and the amide, and moderately by 13,14-methylene derivatives, while 7,8- and 9,10-methylene derivatives did not inhibit this desaturation.
67 Sex Pheromones of Thysanoplusia intermixta and T. orichalcea:Identification and Field Tests.
Thysanoplusia intermixta, which inhabits the temperate zone in Japan, is a defoliator of plants in the family Compositae, Apiaceae, and others. By GC-MS analysis, (
Z)-7-dodecenyl acetate, (
Z)-7-dodecen-1-ol, (5
E,7
Z)-5,7-dodecadienyl acetate and (5
E,7
Z)-5,7-dodecadien-1-ol were identified from a pheromone gland extract of the virgin females in a ratio of 18:3:100:13. A lure baited only with the major diene acetate could attract male moths of
T. intermixta in the field. Other minor components had a synergistic effect on the attraction of the diene acetate. The same four components were included in a very different ratio of 100:6:11:1 in the gland extract of
Thysanoplusia orichalcea, a closely related sub-tropical species. The monoene and diene acetates are essential for field attraction, and a 100:11 mixture is an optimum lure for
T. orichalcea males. However, this mixture, including the diene acetate as a minor component, captured very few
T. intermixta males, suggesting the possibility that these two Thysanoplusia species are reproductively isolated from each other by pheromonal communication.
Key Word: Sex pheromone, lepidopteran attractant,
Thysanoplusia intermixta,
Thysanoplusia orichalcea, Noctuidae, Plusiinae, (5
E,7
Z)-5,7-dodecadienyl acetate, (
Z)-7-dodecenyl acetate, reproductive isolation.
68 Substrate Specificity of the Epoxidation Reaction in Sex Pheromone Biosynthesis of the Japanese Giant Looper (Lepidoptera: Geometridae).
Female moths of the Japanese giant looper (
Ascotis selenaria cretacea, Lepidoptera: Geometridae) secrete (
Z,Z)-6,9-
cis-3,4-epoxynonadecadiene as a sex pheromone component. To the pheromone glands of the decapitated females, [19,19,19-D
3](
Z,Z,Z)-3,6,9-nonadecatriene was applied after an injection of pheromone biosynthesis activating neuropeptide. GC-MS analysis of the gland extract showed its specific conversion into the pheromonal
cis-3,4-epoxide indicating that the C
19 triene which had been identified in the gland was a precursor of the pheromone. In order to examine the substrate specificity of the enzyme catalyzing this epoxidation step, several unsaturated hydrocarbons not occurring in the gland were applied to it. Not only (
Z,Z,Z)-3,6,9-trienes with varying chain lengths (C
17, C
18, and C
20 to C
22) but (
Z,Z)-3,6-dienes (C
17, C
19, and C
20) were converted into the corresponding
cis-3,4-epoxides in a rather good yield, while no 6,7- and 9,10-epoxides could be detected. (
Z)-3-Nonadecene was also changed to the
cis-epoxide, but (
E)-3-, (
Z)-2- and (
Z)-4-double bonds in the C
19 chain were not oxidized. These
in vivo experiments revealed that the monooxygenase regiospecifically attacked the (
Z)-3-double bond of straight chain hydrocarbons regardless of their length and degree of unsaturation.
Key Words: Sex pheromone, biosynthesis, substrate specificity,
cis-3,4-epoxidation, geometrid moth, Japanese giant looper,
Ascotis selenaria cretacea
69 Resolution of Epoxydienes by Reversed-Phase Chiral HPLC and Its Application to Stereochemistry Assignment of Mulberry Looper Sex Pheromone.
Resolution of insect pheromonal cis-epoxydiene racemates derived from (
Z,Z,Z)-3,6,9-trienes was examined utilizing a reversed phase chiral HPLC column. The results showedthat a Chiralcel OJ-R column was suitable for separating the enantiomers having a C
17_C
23 unsaturated straight chain except for 9,10-epoxydienes with a C
21_C
23 chain. To determine the absolute configuration of the separated enantiomers, each of the optically active epoxydienes was hydrogenated over Pd-BaSO
4 and its behavior was examined on this chiral column by co-chromatography with the corresponding chiral epoxy compound having a saturated chain, which was prepared via a Sharpless epoxidation reaction. This analysis showed that the dextrorotatory C
17_C
23 3,4- and 6,7- epoxydienes and C
17_C
20 9,10-epoxydienes with shorter
Rts possess (3
S,4
R)-, (6
S,7
R)-, and (9
R,10
S)-configuration, respectively, and the levorotatory enantiomers with longer
Rts possess the opposite configuration. Furthermore, applying this chiral HPLC, it was revealed that an abdominal tip extract of the mulberry looper,
Hemerophila artilineata Butler (Lepidoptera: Geometridae: Ennominae), included (9
S,10
R)-(
Z,Z)-
cis-9,10-epoxy-3,6-octadecadiene as a main sex pheromone component. The synthetic (9
S,10
R)-9,10-epoxydiene, rather than its antipode, elicited strong antennal and behavioral responses from the male moths in electrophysiological and field tests.
Key Words: Chiral column, reversed phase HPLC, resolution, sex pheromone, lepidopteran attractant, stereochemistry, epoxydiene, mulberry looper
70 Chiral HPLC Resolution of Monoepoxides Derived from 6,9-Dienes and Its Application to Stereochemistry Assignment of Fruit-piercing Noctuid Pheromone.
The resolution of insect pheromonal
cis-monoepoxy racemates derived from (
Z,Z)-6,9-dienes was examined employing chiral HPLC columns, and the results showed that a normal-phase column (Chiralpak AD) was suitable for both 6,7- and 9,10-epoxides with a C
17-C
23 straight chain, as was a reversed-phase column (Chiralcel OJ-R) for the 6,7-epoxides. To determine the absolute configuration of each separated enantiomer applying a modified Mosher's method, the epoxy ring was opened by methanolysis, and the
1H-NMR data of (
S)- and (
R)-MTPA esters of the methoxyalcohols produced were analyzed. Further, the hydrogenated product of each enantiomer was chromatographed on the OJ-R column referring to the corresponding authentic chiral compounds with a saturated chain, which were prepared by a Sharpless epoxidation reaction. These analyses showed that the levorotatory 6,7- and 9,10-epoxides with shorter
tRs possess 6
S,7
R and 9
R,10
S configuration, respectively, and the dextrorotatory enantiomers with longer
tRs possess the opposite configuration. Utilizing this chiral HPLC, it was revealed that an abdominal tip extract of the fruit-piercing moth,
Oraesia excavata Butler (Lepidoptera: Noctuidae), included (9
S,10
R)-(
Z)-9,10-epoxy-6-henicosene as a main sex pheromone component. The synthetic 9,10-epoxide with this configuration, which was separated from the racemate, exhibited stronger activity in electrophysiological and field tests against male moths than the enantiomer.
Key Words: Sex pheromone, Lepidoptera, chiral HPLC, stereochemistry, (9
S,10
R)-(
Z)-9,10-epoxy-6-henicosene, fruit-piercing moth,
Oraesia excavata
71 Responses of Japanese Giant Looper Male Moth to Synthetic Sex Pheromone and Related Compounds.
The Japanese giant looper,
Ascotis selenaria cretacea, is a serious defoliator of tea gardens in Japan. In Mie Prefecture male moths were dose-dependently attracted to rubber septa baited with 0.1-10.0 mg of the sex pheromone component (
Z,Z)-6,9-
cis-3,4-epoxynonadecadiene. Monitoring by pheromone traps showed three flight periods (June, July, and August-September). A septum with a 1mg dose was still active after exposure for over three months in the field, but the number of males captured by the old lure was one fifth of that captured by a fresh lure. The parent 3,6,9-triene, a minor pheromonal component, showed a synergistic effect on male attraction when mixed with the pheromonal epoxydiene at a very low ratio, but the 1:1 mixture hardly captured any male moths. Attraction was also effectively inhibited by the positional isomers (6,7- and 9,10-epoxydienes), which exhibited rather strong electrophysiological activities on the male antennae. When these related compounds were placed around a trap baited with the synthetic pheromone, the number of captured moths remarkably decreased, which indicates the possibility of using the compounds as a disruptant.
Key Words: Sex pheromone, attractant, Japanese giant looper,
Ascotis selenaria cretacea, (
Z,Z)-6,9-
cis-3,4-epoxynonadecadiene, field attractant, disruption, electroantennogram
72 A Convenient Preparation of Optically Active Diepoxyhenicosene (Leucomalure), Lymantrid Sex Pheromone, by Chiral HPLC.
From optically active (3
Z,9
Z)-
cis-6,7-epoxy-3,9-henicosadiene (2), all stereoisomers of (3
Z)-
cis-6,7-
cis-9,10-diepoxy-3-henicosene [leucomalure (1)], a sex pheromone component of the Satin moth, were prepared in addition to the
cis-3,4-
cis-6,7-diepoxy analog (3). Specifically, MCPBA oxidation of each enantiomer of this epoxydiene yielded a mixture of four compounds, namely two diastereomeric sets of leucomalure and the positional isomer, which were easily separable by chiral HPLC equipped with either a Chiralpak AD column or a Chiralcel OJ-R column. Their chemical structures were determined by 2D-NMR analyses, and it was further confirmed that the chiral HPLC columns also had a high capability of resolving the enantiomers of these diepoxides.
Key Words: Diepoxy sex pheromone, chiral HPLC, resolution, stereochemistry, diepoxyhenicosene, leucomalure, lymantrid Satin moth
