Synthesis of 2-Acetylbenzo[b]thiophenes

Chemburkar et al. have reported an efficient method for synthesis of 2-acetylbenzo[b]thiophene derivatives. According to their results, the synthesis involves treatment of 2-chlorobenzaldehyde with tert-butyl mercaptan to form 2-(tert-butylthio)benzaldehyde, which upon treatment with HBr in water gives the disulfide derivative. Then, the reaction with acetylacetone and chloroacetone gives 2-acetylbenzo[b]thiophene, the key intermediate for zileuton, which is used for asthma treatment.