Keimei Fujimoto

Optically Active Trimethylcyclopropanecarboxylic Acids

Four optically active trimethylcyclopropanecarboxylic acids were prepared from chrysanthemic acids, and their absolute configurations were determined on the basis of chrysanthemic acids whose configuration were already known. Toxicities of several rethronyl esters towards housflies were compared with those of chrysanthemic acids and the cis-acids were proved to be more effective than the trans-acids.

Studies on Organophosphorus Insecticides: Part IX. Preparation and Biological Properties of PhenylphosphonothioatesPart X. Chemical and Biological Properties of O,O-Dimethyl-O-(4-cyanophenyl) phosphorothioate and O-Ethyl-O-(4-cyanophenyl) phenylphosphonothioate

Various insecticides belonging to the O-alkyl-O-(subst. phenyl) phenylphosphonothioate family were prepared and their biological activities studied. Besides O-ethyl-O-(4-nitrophenyl) phenylphosphonothioate, which is utilized in these days, another compound, O-ethyl-O-(4-cyanophenyl) phenylphosphonothioate, proved to have excellent properties as an insecticide.In our previous paper, it was reported that O,O-dimethyl-O-(4-cyanophenyl) phosphorothioate (S-4084) has only a low toxicity towards mammals though possessing a high activity towards rice stem borers. In this paper, the chemical and biological properties of S-4084 and its phenylphosphonothioate derivative (S-4087) will be reported in detail. It should especially be noted that S-4084 had a higher activity towards rice stem borers than S-4087 by topical or pot test in a room or in a green-house, but by field test S-4087 was stronger than S-4084.