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Synthesis of 2‐amino‐4‐imino‐4,5‐dihydrothiazoles from N ‐sulfonyl‐α‐chloroamidines and thiourea
Author(s) -
Abdelaal Salma M.,
Bauer Ludwig
Publication year - 1988
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570250648
Subject(s) - thiourea , chemistry , sulfonyl , alkyl , medicinal chemistry , hydrochloride , yield (engineering) , acetone , amine gas treating , carbon 13 nmr , organic chemistry , materials science , metallurgy
A number of new and interesting 2‐amino‐4‐( N ‐substituted)imino‐4,5‐dihydrothiazoles were synthesized by reacting thiourea (or thiourea hydrochloride) with N ‐alkyl‐ or N,N ‐dialkyl‐ N ′‐ p ‐toluenesulfonyl‐α‐chloroacetamidines, where the N,N ‐alkyl groups were ethyl, cyclohexyl, benzyl, β‐phenethyl, (3,5‐dimethyl‐1‐adamantyl)‐methyl, as well as N,N ‐dimethyl‐ and N,N ‐pentamethylene. Reactions of N ‐alkyl‐ N ‐ p ‐toluenesulfonyl‐2‐chloroacetamidines (substituents being N ‐ethyl, N ‐benzyl and N,N ‐dimethyl) with thiourea hydrochloride in hot 2‐propanol furnished 2‐amino‐4‐( p ‐toluenesulfonyl)imino‐4,5‐dihydrothiazole (in 51, 60 and 65% yields, respectively) and the corresponding amine hydrochloride. In hot acetone or butanone, the reactions of these N ‐sulfonyl‐2‐chloroacetamidines with excess thiourea provided 2‐amino‐4‐ N ‐(alkyl or N,N ‐dialkyl)imminium‐4,5‐dihydrothiazole chlorides in 25–80% yield. The by‐product from these reactions was p ‐toluenesulfonamide. The structures of the products were established by chemical transformations and spectral methods (nmr and mass spectra).