Thiazoles, trifluoromethyl-, from

Thiazolines 186 and 187 were prepared from acetic and benzoic thioamides and bis-trifluoromethyl enone 188. Benzoic thioamide underwent oxidation readily upon treatment with />-toluenesulfonic acid (PTSA) to form the corresponding thiazole 189, whereas methyl variant did not (Scheme 72) <2003JST(646)1>. 

From this work, F5183, 5-(5-methylthienyl)-2-(4-trifluoromethyl phenyl)thiazole, emerged as a field candidate. This compound demonstrated excellent initial and residual activity against both susceptible and resistant TSM in the laboratory. Table VIII gives the comparative biological activity of F5183 to other photoactivated mitiddes. 

A radical trifluoromethylation is widely used for incorporation of CF3 group into thiazole ring. This is simple and therefore promising procedure as an industrial process. Trifluoromethyl radical has electrophilic nature and can be readily generated from various sources. For example, the reaction of thiazoles with CF3I is carried out in the presence of Fe (II), H2O2 and DMSO under mild conditions [7]. In this case usual orientation of electrophilic substitution was observed. 

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