Stereoselective response of tribolium castaneum herbst and Musca domestica L. against optically active 2-methoxy-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide

Abstract

1. The optical isomers of 2-methoxy-5-phenyl-l,3,2-oxazaphospholidine 2-sulfide (5-PMOS) were synthesized by a chiral two-step phosphorylating method, and their absolute configurations and optical purities were determined by ¹H-NMR.

2. (S)c(R)p-trans-5-PMOS showed the highest activity and the activity decreased in the order of (S)c(R)p-trans->(R)c(R)p-cis->(R)c(S)p-trans->(S)c(S)p-cis-5-PMOS in reducing larval growth and inhibiting acetylcholinesterase (AChE) of the red flour beetle Tribolium castaneum Herbst.

3. (R)c(R)p-cis-5-PMOS showed the highest anti-AChE activity followed by (R)c(S)p-trans- >(S)c(R)p-trans->(S)c(S)p-cis-5-PMOS, corresponding with insecticidal activity against Musca domestica L.

4. Optical isomers of 5-PMOS were not effective in stimulating adenylate cyclase prepared from ventral nerve cords of Periplaneta americana L.

5. The reversed stereospecificity between the T. castaneum larval growth-inhibitory and M. domestica insecticidal activities of 5-PMOS optical isomers is due to a stereospecific difference in the intrinsic potency of active form of 5-PMOS isomers as AChE inhibitors with the two insects.