Phosphinecarbothioamide formation in the reaction of tetrazolylsulfinylmethyl(dimethyl)phosphine oxide with amines

In the study of the thermolysis of heteroaryl substituted sulfoxides, we examined the same reaction in the presence of several amines, such as aniline, benzylamine, and morpholine. In the case of 5-(1-phenyl)-1,2,3,4-tetrazolylsulfinylmethyl(dimethyl)phosphine oxide ( 1 ), the corresponding phosphinecarbothioamide 2 were unexpectedly obtained in moderate yields together with 1-phenyl-1,2,3,4-tetrazole ( 3 ). These products are considered to be formed by the addition reaction of amines to the sulfine formed initially and then elimination of H 2 O.