20 Systematic Syntheses and Characterization of Dodecadien-1-ols with Conjugated Double Bond, Lepidopterous Sex Pheromones.
Four geometrical isomers of 5,7-, 6,8-, 7,9- and 8,10-dodecadien-1-ols were systematically synthesized by two routes. One involved the Wittig reaction between (
E)-2-alkenal and a phosphorane with an appropriate carbon chain, and yielded a mixture of (
E,Z)- and (
E,E)-isomers in a ratio of
ca. 3:2. The other route comprised of the Wittig reaction of a 2-alkynal and the stereoselective reduction of the tripe bond to a (
Z)-double bond
via hydroboration with dicyclohexylborane to give a mixture of (
Z,Z)- and (
Z,E)-isomers in a ratio of 6:1 ? 10:1. Both the mixtures were separately chromatographed on a silica gel column impregnated with silver nitrate to give four geometrically pure isomers. With 9,11-diene, they were analyzed by GC on a capillary column, HPLC, silver nitrate impregnated TLC, and
13C NMR.
22 Mass Spectra of Dodecadienic Compounds with a Conjugated Double Bond, Lepidopterous Sex Pheromones.
All geometrical isomers of 5,7-, 6,8-, 7,9-, 8,10- and 9,11-dodecadien-1-ols, and their acetates and aldehyde derivatives were analyzed by electron impact mass spectrometry. The abundance of molecular ion (M
+) was observed in every spectrum, and the relative intensity of M
+ tended to be strong if the compound possessed an (
E)-double bond(s). In addition to M
+, [M?H
2O]
+ (alcohols) and [M?CH
3CO
2H]
+ (acetates), every dienic compound showed typical series of C
nH
2n-2+ ? C
nH
2n-5+ with abundance maxima around C
4, C
5, C
6 or C
7. Each double bond positional isomer characteristically yielded different ion peaks in the series, which were useful for its distinction from other isomers. These results indicate that the chemical structure of a natural pheromone of Lepidoptera is easily deduced successfully by GC-MS analysis if it is a conjugated dienic pheromone.
29 Lepidopterous Sex Attractants with a Conjugated Diene System.
Each of fifty-on conjugated dienes (alcohols, acetates and aldehydes) with a C
12, C
14 or C
16 straight chain was applies to a rubber cap in a sticky-type trap as a single-component lure. Some diene compounds were mixed with their functional derivatives or structurally related monoenes to make two-component lures. In field trials conducted from 1984 to 1986, the new attraction of male moths of nineteen species was observed. These species were classified into nine families as follow: Gracillariidae, Yponomeutidae, Oecophoridae, Cosmopterigidae, Tortricidae (Olethreutinae and Tortricinae), Pyralidae, Pterophoridae and Geometridae. This result indicated that the conjugated dienes are one of the main groups of lepidopterous sex pheromones. Some interesting information concerned with the taxonomy of the attracted moths and with the characteristics of the chemical structures of their attractants was observed.
30 Sex Pheromone Biosynthesis from 14C-Hexadecanoic Acid in the Silkworm Moth.
[16-
14C]Hexadecanoic acid in dimethyl sulfoxide was applied topically to a sex pheromone gland of the silkworm moth,
Bombyx mori L. By the combination of normal-phase TLC and reversed-phase TLC or HPLC, bombykol (the sex pheromone of this species, (10
E,12
Z)-10,12-hexadecadien-1-ol) was purified, and its
14C-incorpoation was successfully counted without any contamination by other components in the gland. The highest incorporation ratio (
ca. 1.5%) of the
14C-acid into bombykol was observed when a 1-day-old virgin female was treated 4 hr after lighting under a 16:8 light-dark cycle, the gland being excised for extraction 1 or 3 hr after the treatment. This reliable incorporation is suggested to be useful for further investigations of the biosynthetic pathway. The
14C-acid was also incorporated into other components in the pheromone gland, which have been proposed as precursors of bombykol biosynthesis, namely the (10
E,12
Z)-10,12-hexadecadienoic acid and (
Z)-11-hexadecanoic acid moieties, hexadecan-1-ol, and (
Z)-11-hexadecen-1-ol. The total recovery of radioactivity attained
ca. 20%, including the unchanged
14C-acid.
31 Biosynthetic Pathway of Bombykol, the Sex Pheromone of the Female Silkworm Moth.
For investigation of the biosynthetic pathway of bombykol ((10
E,12
Z)-10,12-hexadecadien-1-ol, the female sex pheromone of the silkworm moth), some
14C-labelled compounds were applied to pheromone glands of 1-day-old virgin female moths 4 hr after lighting (25-27 hr after eclosion), and their incorporation into the pheromone was measured by the succeeding fractionation with normal-phase and reversed-phase TLC plates. [1-
14C](
Z)-11-Hexadecenoic acid changed more easily to bombykol than [1-
14C]hexadecanoic acid, while [1-
14C](
E)-11-hexadecenoic acid and [1-
14C]hexadecan-1-ol were scarcely incorporated into the pheromone. This result confirms the biosynthetic pathway
via (
Z)-11-hexadecenoate and (10
E,12
Z)-10,12-hexadecadienoate, which has been proposed by Yamaoka
et al. and Bjostad and Roelofs. Some [1-
14C](
Z)-11-hexadecen-1-ol was changed to bombykol, suggesting that the alcohol was oxidized to (
Z)-11-hecadecenoic acid and this acid was taken into the biosynthetic pathway.
33 Mass Spectra of Lepidopterous Sex Pheromones with a Conjugated Diene System.
Dodecadien-1-ols, tetradecadien-1-ols and hexadecadien-1-ols with a conjugated (
E,E)- or (
E)-diene system between the ω1,ω3- and ω5,ω7-positions, their acetates, and aldehyde derivatives (lepidopterous sex pheromones and candidates) were analyzed by electron impact mass spectrometry, which was operated at 70 eV ionization voltage. Three functional derivatives with a same diene system presented a similar spectral pattern, except for the molecular ions (M
+), [M-H
2O]
+ of the alcohols and [M-CH
3CO
2H]
+ of the acetates. Each isomer showed a characteristic ion series of C
nH
2n-2+ ? C
nH
2n-5+ (C
4 ? C
9), which reflected the double-bond position in the molecule, indicating a method for determining the position of a natural diene pheromone by comparing its mass spectrum with those of the synthetic dienes. By this method, the natural pheromone of
Hellula undalis was confirmed to be a ω3,ω5-diene. Furthermore, the fitness indexes proposed by Kuwahara
et al., were calculated for some pheromone components, using the mass spectra of synthetic dienes, in order to examine the possibility and limitation for applications of those mass spectra to natural pheromone studies.
34 Syntheses and NMR Analyses of Eight Geometrical Isomers of 10,12,14-Hexadecatrienyl Acetate, Sex Pheromone Candidates of the Mulberry Pyralid.
Eight geometrical isomers of 10,12,14-hexadecatrienyl acetate, female sex pheromone candidates of the mulberry pyralid (
Glyphodes pyloalis Walker), were synthesized by six routes. Each route consisted of reactions by which two of three double bonds were introduced stereospecifically and another rather nonspecifically, giving mainly two geometrical isomers, which were analyzed by 2D-NMR after separating by reversed-phase HPLC or by a reaction with tetracyanoethylene. The signals of the olefinic protons and carbons of each geometrical isomer were assigned by COSY spectra and by C-H COSY spectra, respectively, in addition to the signals of the allylic protons and carbons, and its chemical structure was revealed by the values of their chemical shifts and coupling constants. Furthermore, a new empirical rule concerning the chemical shift changes of these carbons by converting the configuration of the conjugated triene system is suggested.
36 Amino Acid Sequence of Pheromone-Biosynthesis-Activating Neuropeptide (PBAN) of the Silkworm, Bombyx mori.
We have isolated two distinct pheromone-biosynthesis-activating neuropeptides (PBAN), named PBAN-I and -II, as fully oxidized forms of Met residues from adult heads of the silkworm,
Bombyx mori. PBAN-I was identical with the PBAN which we had isolated before. The complete amino acid sequence of PBAN-I, a total of 33 amino acid residues, was determined as H-Leu-Ser-Glu-Asp-Met-Pro-Ala-Thr-Pro-Ala-Asp-Gln-Glu-Met-Tyr-Gln-Pro-Asp-Pro-Glu-Glu-Met-Glu-Ser-Arg-Thr-Arg-Tyr-Phe-Ser-Pro-Arg-Leu-NH
2. Synthetic PBAN-I after oxidation with H
2O
2 was chromatographically identical with the isolated PBAN-I. Examination of PBAN activity of synthetic analogues indicated that the carboxyl-terminal portion of PBAN-I was important for biological activity.
