Casida_1963_Biochem.Pharmacol_12_73

The following types of phosphorus compounds were found to be active in potentiating the toxicity of malathion to mice: triphenyl phosphates and phosphonates containing o- and p-, methyl and ethyl substitutents; certain di-(substituted-phenyl) phenylphosphonates and N-methylphosphoramidates; S,S,S-trialkyl phosphorotrithioites and phosphorotrithioates; and certain saligenin cyclic phosphorus esters. Some compounds in the latter two groups also produced ataxia in hens. Certain of the saligenin cyclic phosphorus esters were as potent in effecting ataxia as the dialkyl phosphorofluoridates, but required much larger doses to produce parasympathomimetic effects. Also considered are the activity of the 112 phosphorus esters investigated for inhibition in vitro of mouse plasma esterases hydrolyzing malathion and propionylcholine, and the stability of the saligenin cyclic phosphorus esters to enzymatic and nonenzymatic hydrolysis."