Intermediates in the halogenation of some 2-aminothiazoles

Abstract

Halogenation of 2-aminothiazoles in various solvents to produce 2-amino-5-halogenothiazoles proceeds via an addition–elimination mechanism. The addition products (Δ²-thiazolines) have been isolated and characterized by their n.m.r. spectral properties. The high regiospecificity and stereospecificity of the addition step are discussed. In these reactions, the behaviour of the C(4)–C(5) double bond in 2-aminothiazoles is similar to that of the double bond in ethylenes.