10 Sex Pheromone of the Rice Green Caterpillar: Chemical Identification of Three Components and Field Tests with Synthetic Pheromone.
The sex pheromone of the rice green caterpillar,
Naranga aenescens Moor, was presumed to be a mixture of some unsaturated acetates using electroantennogram technique. Abdominal tips of virgin females were shown to contain (
Z)-9-tetradecenyl acetate (compound
I), (
Z)-9-hexadecenyl acetate (compound
II) and (
Z)-11-hexadecenyl acetate (compound
III) in a ratio of 1:1:4, respectively. These synthetic three compounds were individually active on the male antenna but only the mixture of the three compounds attracted the male moths in a field. Field traps containing the three compounds in a ratio of 1:1:4 (1 mg/rubber septum) consistently attracted more males than traps baited with two unmated females.
11 (Z)- and (E)-12-Tetradecenyl Acetates: Sex Pheromone Components of Oriental Corn Borer (Lepidoptera: Pyralidae).
The female sex pheromone of the oriental corn borer,
Ostrinia furnacalis Guenee, was presumed to be composed of (
Z)-12-tetradecenyl acetate and its geometrical isomer using electroantennogram technique. From the extracts of female moths, the presence of these compounds in a ratio of ca. 3:2 was confirmed by gas-liquid chromatography and gas-liquid chromatography combined with mass spectrometry in selected ion monitoring mode. Since the male moths were not attracted to mixtures of the two synthetic compounds, the presence of minor component(s) was suggested.
12 Multi-component Sex Attractants in Systematic Field Tests of Male Lepidoptera.
More than 100 multi-component lures consisting of primary straight chain alkenols, their acetates and alkenals were prepared and tested as attractants of male lepidopterous insects. In field trials, male moths of 52 species were specifically attracted to two- or three-component lures. Further 35 lepidopterous species were found to be attracted to single component lures used as control. The main families captured by the multi-component lures were Tortricidae (24 species), Noctuidae (11 species) and Acrolepiidae (3 species). This successful attraction of so many species indicates the usefulness of systematic field tests using multi-component lures of selected synthetic chemicals.
13 (5Z,7E)-5,7-Dodecadien-1-ol: Female Sex Pheromone of the Pine Moth Dendrolimus spectabilis Butler.
The sex pheromone of the pine moth
Dendrolimus spectabilis Butler was tentatively identified as 5,7-dodecadien-1-ol by the use of the electroantennogram technique. Analyses of abdominal tip extracts of virgin females by gas-liquid chromatography and mass spectroscopy showed the presence of a (5
Z,7
E)-isomer and a (5
E,7
E)-isomer in the ratio of about 5:1. In field examinations with four synthetic isomers of 5,7-dedecadien-1-ol, only traps baited with the (5
Z,7
E)-isomer captured an appreciable numbers of male moths.
14 Stereoselective Synthesis of Some Isomers of Dodecadien-1-ol: Compounds Related to the Pine Moth Sex Pheromone.
Four isomers of 5,7-dodecadien-1-ol were previously proposed as being the sex pheromone of the pine moth. The isomers were stereoselectively synthesized from 1-hexyne and tetrahydropyranyl ether of 5-hexyn-1-ol. The (5
Z,7
Z)-isomer was synthesized by a Chodkiewic Cadiot reaction followed by hydroboration, and other three isomers by novel synthetic methods including the addition of zirconocene hydride [Schwarz’s reagent (C
5H
5)
2Zr(H)Cl] to control the regioselective coupling reaction. The 5,8- and 5,9-dodecadien-1-ols were also synthesized by similar methods for comparison of their characteristics with the endogenous sex pheromone.
16 Conversion of (S)-Allethrolone to Pyrethrin I, Jasmolin I Cinerin I, and [propenyl-3-13C]- and [propenyl-3-14C]-(S)-Bioallethrin.
Pyrethrin I, jasmolin I, and cinerin I of high stereochemical purity were prepared from (
S)-allethrolone by the following reaction sequence: protection of the hydroxyl and reduced carbonyl groups as their acetate and tetrahydropyranyl derivatives, respectively; ozonolysis to convert the propenyl compound to a key formylmethyl intermediate; Wittig reaction of this aldehyde with ylides derived from allyl-,
n-propyl-, or ethyltriphenylphosphonium halide; cleavage of the tetrahydropyranyl ether and oxidation of the cyclopentenol to the cyclopentenone with pyridinium chlorochromate; separation of the
Z and
E isomers of the rethronyl acetates, hydrolysis, and esterification of the optically pure pyrethrolone, jasmolonone, and cinerolone with (1
R)-
trans-chrysanthemoyl chloride. An extension of this synthesis via 3-[(1
R)-
trans-chrysanthemyloxy]-2-methyl-5-[(tetrahydro-2
H-pyran-2-yl)oxy]-1-cyclopentene-1-acetaldehyde as the critical intermediate allows isotopic label introduction by Wittig reaction near the terminal step, as illustrated with [
propenyl-3-
13C]- and
[propenyl-3-
14C]-(
S)-bioallethrin of high isomeric and radiochemical purities. Stereochemical assignments are supported by appropriate optical rotation values and complete
1H and
13C NMR data.
17 3-(3,3-Dihalo-2-propenyl) Analogues of Allethrin and Related Pyrethroids: Synthesis, Biological activity, and Photostability.
Allethrin analogues with 3-(3,3-dihalo-2-propenyl) substituents are prepared by Wittig reaction of a formylmethyl intermediate, from ozonolysis of allethronyl acetate, with appropriate dihalomethylene ylides and then hydrolysis and reesterification to obtain the (1
R)-
trans-chrysanthemates, (1
R)-
cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylates, and 2,2,3,3-tetramethylcyclopropanecarboxylates. Compared with the propenyl compounds, the difluoropropenyl counterparts in each series are generally more insecticidal whereas the dibromo- and dichloropropenyl analogues of allethrin are less toxic to houseflies. There is surprisingly little difference in the toxicity of the above pyrethroids and of cinerin I, jasmolin I, and the 3-(3-methyl-2-butenyl) analogue to piperonyl butoxide treated flies, but they are all less potent than synergized pyrethrin I. The photoreaction rate as thin films is influenced by the 3-substituent of the rethronyl moiety,
i.e., (
Z)-2,4-pentadienyl > (
Z)-2-butenyl or -pentenyl or -3-methyl-2-butenyl > 2-propenyl or 3,3-difluoro-2-propenyl > 3,3-dichloro- or 3,3-dibromo-2-propenyl. The propenyl substituent of [
propenyl-3-
13C]-
S-bioallethrin is photoconverted (
13C NMR) to cyclopropyl and 2,3-epoxypropyl groups.
18 13C NMR Analyses on Conjugated Dienic Pheromones of Lepidoptera.
13C NMR spectra of all the geometrical isomers of 5,7- and 8,10-dodecadien-1-ols and 9,11-dodecadienyl acetate were studied, and a new method for assigning
13C signals of a conjugated system is proposed. The method is based on two empirical rules. The first involves the
13C shift differences of olefinic carbons induced by a substitutional change at an end of the conjugated diene system, namely the change from a methylene to a methyl at C
f in the C
a-C
b=C
c-C
d=C
e-C
f diene system. The second rule concerns the chemical shift changes of allylic and olefinic carbons by converting the geometry of conjugated diene systems. Namely, when the (
E)-configuration of a C
b=C
c double bond in the diene system is changed into a (
Z)-configuration without the conversion of the C
d=C
e double bond, the signals of C
a, C
b, C
c and C
d shift upfield by 5.1 ± 0.3, 2.6 ± 0.3, 1.9 ± 0.3 and 4.9 ± 0.2 ppm, respectively, and the signal of C
e downfield by 2.2 ± 0.2 ppm, regardless of the geometry of the C
d=C
e double bond.
19 The Biosynthetic Pathway of (Z)-11-Hexadecenal, the Sex Pheromone Component of the Rice Stem Borer, Chilo sappressalis WALKER (Lepidoptera: Pyralidae).
The sex pheromone of the rice stem borer,
Chilo sappressalis WALKER (Lepidoptera: Pyralidae), (
Z)-11-hexadecenal, was biosynthesized by feeding experiments with possible deuterized precursors and tested by a GC-SIM analysis of the pheromone component. The pathway commenced by hexadecanoic acid being reduced to the hexadecanal, from which (
Z)-11-hexadecenal was biosynthesized by the introduction of a double bond.
