Synthesis and Biological Testing of Ester Pheromone Analogues for Two Fruitworm Moths (Carposinidae)

Abstract

A range of ester pheromone analogues for carposinid moths were synthesized and evaluated for biological activity. The analogues aimed to take advantage of the structural commonality of (7Z)-alken-11-ones found in this family. Analogues were tested on two pest species: Heterocrossa rubophaga and Coscinoptycha improbana. Two of the analogues, (2Z)-nonenyl nonanoate and (4Z)-heptyl undecenoate, elicited significant electroantennogram responses. Only (4Z)-heptyl undecenoate gave consistent responses with both moth species in single sensillum recording. Field trapping trials were conducted with these two analogues both individually and in combination with the pheromone of each of the two moth species. No attraction was observed to either of the analogues alone, by either moth species. However, when (4Z)-heptyl undecenoate was coupled with the pheromone, it produced a strong inhibitory effect in H. rubophaga, reducing male moth trap catch by over 95%. No inhibitory effect on male moth trap catch was observed in C. improbana.

Synthesis and Electrophysiological Testing of Carbonyl Pheromone Analogues for Carposinid Moths

“…■ RESULTS AND DISCUSSION Synthesis. Starting with the previously prepared pheromone component (Z)-nonadec-12-en-9-one (1), 11 a series of functional group interconversions were attempted (Scheme 1). This began with the methylene analogue, (Z)-11-methylenenonadec-7-ene (2), which was prepared via Wittig olefination.…”

“…Investigation in the literature showed that Camps et al had experienced similar problems with Lawesson reagent when trying to prepare moth pheromone-like structures and had to resort to more complicated methods, so attempts to form the thione were abandoned. 13 In a similar fashion to the functional group transformations listed above, the methyl ether analogue, (Z)-11-methoxynonadec-7-ene (6), was prepared from the alcohol precursor of the pheromone, 11 (Z)-nonadec-12-en-9-ol (5) (Scheme 2).…”

“…Here, (Z)heptyl undec-4-enoate and (Z)-non-2-enyl nonanoate had given antennal responses from both moth species, while (Z)heptyl undec-4-enoate had a strong inhibitory effect on the catch of male raspberry bud moth to pheromone lures in the field environment. 11 It was hoped that this series of analogues would produce more potential pest management tools; unfortunately that was not the case. From comparison with other moth families, it is interesting that only the ester analogues gave responses for the carposinids.…”

“…These have been previously reported and are described briefly here. 11 All NMR spectra were recorded on a 400 MHz Bruker Avance III spectrometer. Chemical shifts are reported relative to the solvent peak of chloroform and/or CDCl 3 (δ 7.26 for 1 H and δ 77.0 for 13 C).…”

“…14 (Z)-Nonadec-12-en-9-one ( 1) and (Z)-nonadec-12en-9-ol (5) were prepared using our previously reported methods. 11 Briefly, these methods consisted of the acid catalyzed hydration of 2,3-dihydrofuran, followed by Wittig olefination favoring the cis double-bond geometry, giving (Z)undec-4-en-1-ol. Dess−Martin oxidation of the alcohol gave the related aldehyde, and Grignard addition gave the desired alcohol (5).…”