A convenient synthesis of symmetrical N,N′-dialkylureas by the reactions of 4-chloro-5H-1,2,3-dithiazol-5-one with alkylamines

Treatment of 4-chloro-5H-1,2,3-dithiazol-5-one with primary and secondary alkylamines (>2 equiv.) in CH2Cl2 at rt afforded symmetrical N,N′-disubstituted ureas in moderate to good yields. Similarly, the reactions with amino acid ester hydrochlorides in the presence of Et3N (>3 equiv.) under the same conditions gave symmetrical ureas.