Synthesis And Bioassaye Of Chilo Partellus Female Sex Pheromones And Their Analogues

Abstract

Synthetic sex pheromones could provide valuable alternative

means of pest control in Integrated Pest Management (IPM)

strategies. Their uses could include population monitoring with

pheromone traps to guide other control methods, by mass trapping

and mating disruption.

(Z)-ll-Hexadecenal (Z-11-C4Hg CH=CH (CHZ) 9 CHO) and (Z)-llhexadecen-

l-ol (Z-ll-C/H",CH=CH(CH1 )oCH10H), the major components of '1 £ J £.

spotted stalk borer, Chilo pert el Lue (swinhoe) fernale sex

pheromone, were prepared in good yields from readily available

l,10-decanediol by an acetylenic route, and (Z) -9-tetradecenyl

fonnate (Z-9-C"HnCH=CH(CH1),CH10-CHO), an analogous structure -was 't j £ J l.

prepared from l,S-octanediol by the analogous acetylenic route.

Simple distillation of the 1-bromo-l0-(2-tetrahydropyranyloxy)

decane, coupling with 1-hexyne in liquid ammonia and litharnide

followed by deprotection gave ll-hexadecyn-l-01 (CIHoC=C(CH1)OCH10H) 1 J £.1"

(b.p 96-9S0 C/0.04 mmHg; 75% yield). Partial hydrogenation of 11-

hexadecyn-l-ol on a Lindlar catalyst gave (Z)-ll-hexadecen-l-ol

(b.p 75° C/O.Ol mmHg, 95% yield) which on oxidation gave (Z)-llhexadecenal

(Z-11-C!HaCH=CH(CH1)nCHO) (b.p 71° C/O.Ol mmHgi SO% ': ) I. '}

yield) containing 1.3% of the (E) isomer by GC analysis on a methyl

silicone column. (E)-11-Hexadecenal and (E)-11-hexadecen-l-ol were

prepared via sodium/liquid ammonia reduction of the intermediate

- "T"T !-"-I"(="1J"g*' _.T...TI1' 1 j 1 nom1Hn.l:-,

, £ .LV giving the final product containing 1% of. the

(Z)-isomer. Pyridinium chlorochromate in dichloromethane was used

for the oxidation of the olefinic alcohols to the corresponding

xiv

aldehydes (yield, 76-79%). The other analogues were obtained by

derivatizing the aldehydes or alcohols of the intermediates or the

final products in the synthesis.

The Electroantennographic (EAG) tests showed that the

compounds differed in their ability to evoke EAG responses and they

were lower than (Z)-ll-hexadecenal. The EAG responses conf inned

that (Z)-ll-hexadecenal was a better stirnulant

corresponding alcohol (Z)-ll-hexadecen-l-ol.

than the

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