Substitution at 4-position in 1,2,3σ2-diazaphosphole by phosphorus trichloride

Abstract

2-Methyl-1,2,3σ²-diazaphospholes are obtained as hydrochlorides from methylhydrazones and an ecxess of PCl₃ which, with longer reaction times, give the 4-dichlorophosphino-derivatives; 4-alkyl substituted diazaphospholes may be separated from their mixture with 4-unsubstituted compounds by the use of this reaction.