Highly regioselective direct halogenation: a simple and efficient method for preparing 4-halomethyl-5-methyl-2-aryl-1,3-thiazoles

An unprecedented C4-methyl regioselective halogenation of 4,5-dimethyl-2-aryl-1,3-thiazoles (1) has been accomplished. The reaction of compound 1 with N-chlorosuccinimide and N-bromosuccinimide under mild conditions provides an efficient and operationally simple method for obtaining 4-chloromethyl-5-methyl-2-aryl-1,3-thiazoles (2) and 4-bromomethyl-5-methyl-2-aryl-1,3-thiazoles (3), respectively, in good yields without the formation of 4-methyl-5-halomethyl regioisomers.