CONFORMATIONAL REQUIREMENTS FOR INHIBITION OF THE PHEROMONE CATABOLISM IN SPODOPTERA LITTORALIS

In the present work we report the results of a molecular modeling study aimed at assessing the conformational requirements for binding to the Spodoptera littoralis antennal esterase. Comparative conformational analysis of the aliphatic chains of a selected group of trifluoromethyl ketone inhibitors, including good and poor analogs (compounds 1‐3 and poor 4‐5, respectively) resulted in a unique bioactive conformation, common to all active analogs. The conformation is open and exhibits its hydrophobic moiety distant from the carbonyl group. The present study also reports the results of an ab initio study on the relative strength of the intramolecular hydrogen bond between the hydrate and the function (O, S, SO and SO2 )i n b position to the carbonyl of some model compounds. The results correlate well with the relative inhibitory effect displayed by the parent trifluoromethyl ketones.