A computational approach of the selective free-radical bromination of 4,5-dimethyl-thiazole with N-bromosuccinimide

Radical bromination of 4,5-dimethylthiazole 1 with different stoichiometrie s of N-bromosuccinimide in the presence of 2,2'-azobisisobutyronitrile affo rded regioselectively mono-, tri- and tetra-bromo compounds 2, 5 and 6 in g ood yields while the dibromo derivatives 3 and 4 were formed without any ap parent selectivity. Computational approaches are developed in order to rati onalize the observed regiochemistry, showing that the whole reaction proces s involves some regioselectivity. (C) 2000 Elsevier Science B.V. All rights reserved.