It is well known that alkyl 4-(halo)-2-chloroacetoacetate and thioacetamide may be reacted to form alkyl 4-halomethyl-2-methylthiazole-5-carboxylates. The process is actually two reactions--cyclization, followed by dehydration. Previous processes for forming thiazoles involved acid catalyzed dehydration.
U.S. Pat. No. 5,045,554 (Alt et al., 9/91), herein incorporated by reference, discloses the reaction of ethyl 4,4,4-trifluoro-2-chloroacetoacetate and thioacetamide to produce ethyl 2-methyl-4-(trifluoromethyl)thiazole-5-carboxylate, which was in turn used to produce fungicidal thiazolecarboxanilides. The reaction produced the thiazole in one step by refluxing the reactants in dimethylformamide, but had only a 38% isolated yield.
However, a process having higher yields is desired for commercial scale production. It is an object of the present invention to provide such a process. It is a further object of the present invention to provide such a process which also results in shorter cycle times, allowing for greater production capacity. It is a still further object of the present invention to provide such a process which also functions at lower temperatures and thus requires less heating, resulting in energy savings.