Studies on Reactions of the <i>N</i>-Phosphonium Salts of Pyridines. XIX. Carbonylation of Amines with Carbon Dioxide by Means of Phosphorus Chlorides in Tertiary Amines

Abstract

Abstract Reactions of carbon dioxide and disulfide with primary amines in the presence of phosphorus chlorides gave the corresponding symmetrically disubstituted ureas and thioureas in high yields under atmospheric conditions. Phosphorus trichloride and di- and mono-chlorophosphites were remarkably effective for the reactions, whereas phosphorus pentachloride and phosphoryl chloride were ineffective. The presence of tertiary amines such as pyridine satisfactorily favored the reactions. The reaction seems to proceed via the N-phosphonium salts of pyridines as those obtained from diphenyl and triaryl phosphites, on the basis of their IR spectroscopic analyses, stoichiometric relationship between reactants and the steric effect of tertiary amines.