Synthesis of 1,3,5-risubstituted 2,4-dithiobiurets: Their conversion into 4-Alkyl-3,5-di(substituted imino)-l,2,4-dithiazolidines and to related benzothiazolylthioureas

Abstract

The interaction of alkyl and aryl isothiocyanates with an equimolar quantity of 1,3-dialkyl- and 1-alkyl-3-aryl-thioureas in the presence of a strong alkali has been found to yield 1-alkyl-or aryl-3-alkyl-5-alkyl- or aryl-2,4-dithiobiurets in excellent yield. The 2,4-dithiobiurets so obtained were easily converted into 1,2,4-dithiazolidine derivatives by oxidation with iodine or bromine in a non- polar medium. The 4-alkyl-3-alkylimino-5-arylimino-1,2,4-dithiazolidine salts were found to undergo a facile thermal rearrangement to the related N-benzothiazol-2-ylthioureas.