ALKYL ETHER AND ENOL ETHER ANALOGS OF (Z)-5-DECENYL ACETATE, A PHEROMONE COMPONENT OF THE TURNIP MOTH, AGROTIS-SEGETUM - PROBING A PROPOSEDBIOACTIVE BIOACTIVE CONFORMATION FOR CHAIN-ELONGATED ANALOGS

In order to test a previous conclusion that chain-elongated analogs of (Z)-5-decenyl acetate (1), a pheromone component of the turnip moth, Agrotis segetum, adopt a loop conformation of the terminal alkyl chain in the bioactive conformation, a series of alkyl ether and enol ether analogs of 1 and (Z)-5-dodecenyl acetate (2) have been synthesized an d tested using single-cell electrophysiology. In these analogs a methy lene group in positions 7 and 9 of 1 and in positions 7 and 11 in 2 ha ve been replaced by an oxygen atom in order to energetically facilitat e the formation of a loop conformation in the chain-elongated analogs. The electrophysiological results in combination with molecular mechan ics (MM2 and MM3) calculated conformational energies show that the act ivity decreases of the chain-elongated ether analogs are significantly smaller than that for 2 and that these activity decreases parallel th e conformational energies for a loop formation of the terminal chains in the analogs. The results support our previous conclusion that the t erminal chain of chain-elongated analogs of 1 adopts a loop conformati on in their bioactive conformations.