A New Synthesis of Thiazole Derivatives via Ring Transformation of 6-Imino-6H- 1,3-thiazine Hydroperchlorates

Abstract

2-Arylthiazoles (8) with a cyanoacetate moiety in position 4 were synthesized by a new ring transformation reaction. Therefore 2-aryl-6-imino-6H-1,3-thiazinecarboxylic ester hydroperchlorates (3) were converted into 2-arylthiazoles (8) by reaction with acceptor substituted halomethanes (e.g. chloroacetonitrile, chloroacetic acid ester or phenacyl bromide). Using 2-(2-hydroxyphenyl)-6H-1,3-thiazinecarboxylic-acid ester hydroperchlorate (3c) as the starting compound the benzoxazine (11a) was obtained. Starting from 2-(4-chlorophenyl)-6H-1,3-thiazine-carboxylicacid ester hydroperchlorate (3b) the thiazolo[5,4-c]pyridine (9e) was the final product.