Study of conjugation in N-methylphosphamidines-systems with a tetrahedral phosphorus atom

Abstract

1. The kinetics of the reaction of P,P-diethyl-N-methyl-N,N′-diarylphosphamidines with methyl iodide was studied. 2. The basicities of P,P-diethyl-N-methyl-N,N′-diarylphosphamidines in nitromethane were determined. 3. The rate constants of methylation and the basicities of P,P-diethyl-N-methyl-N,N′-diarylphos-phamidines are linearly correlated with the Hammett σ constants or with the nucleophilic σ- constants; moreover, in the latter case the correlation is better. 4. From a comparison of the rate constants of methylation and the basicity constants of two series of phosphamidines, it was found that the tetrahedral phosphorus atom in the phosphamidines studied transmit the polar influences of the substituents at the nitrogen atoms without any change in the ratio of the inductive and resonance components, weakening this influence by approximately 50–60%.