Relative reactivity of groups bonded to positions 2 and 5 of the thiazole ring

Abstract

The displacement of halogen by methoxide, methanethiolate, and benzenethiolate ions, and the oxidation of phenylsulphinyl to phenylsulphonyl by perbenzoic acid, in positions 2 and 5 of the thiazole ring have been studied quantitatively. The reactivity ratio (5 : 2) is moderate in every case and the unusual nucleophilic halogen displacement for 5-halogenothiazoles together with the oxidation of the 5-sulphinyl group emphasizes the slightly positive character of C-5.