[Toxic and pharmacological characteristics of armin and nibufin homologs].

The experimental studies of alkylesters of phosphonic and phosphinic acids, close homologues of armine and nibufin, showed this series of compounds to have a strongly marked anticholinesterase action. All the substances produce an inhibitory effect on the central nervous system, raise the tone of the smooth muscles on an isolated strip of rabbit small intestine and induce a miotic pupil in the animals. Introduction of butyl radicals into molecules of phosphonic acid derivatives results in diminution of toxicity and a slight decrease in anticholinesterase activity. By their properties butyl paranitrophenyl esters of ethyl- and butylphosphonic acids are closely related to armine and nibufin.