Structure activity analysis of some O,O-dialkyl (p-methylthio, p-methylsulfonyl) phenyl phosphates and phosphorothioates prepared for their insecticidal activity

Abstract

Multiple regression analysis was used to separate the contribution that the thiomethyl and sulfonylmethyl group as well as the P=0 and P=S groups made on the insecticidal activity in a series of organophosphates. The analysis indicated the possibility that thiomethyl and the P=S group had to undergo transformation to a more reactive species. The biological activity of the series of phosphates rep-resented by the sulfonylmethyl and the P=0 correlated quite well with the partition coefficient and the rate of alkaline hydrolysis. One surprising observation is the indication that the thiomethyl phosphorothioate which is most stable to nucleophilic attack should be the most active as an insecticide.