Synthesis of 2-acyl-benzo[1,3-d]selenazoles via domino oxidative cyclization of methyl ketones with bis(2-aminophenyl) diselenide

A general, practical and simple one-pot synthesis of 2-acyl-benzo[1,3-d] selenazoles was developed by reacting a wide range of 2-arylethane-1,2-diones, generated in situ from commercially available aryl methyl ketones, with bis(2-aminophenyl) diselenide, promoted by Na2S2O5 in DMSO at 100 degrees C. Comparatively, the reactions were conducted under conventional heating and microwave irradiation. The use of focused microwave irradiation drastically decreased the reaction time from 48 to 2 h with a gain in the reaction yield for most cases. Still, 2-phenylacyl-benzo[1,3-d] selenazole was elected to react with sodium borohydride and butylmagnesium bromide, giving the respective secondary and tertiary alcohols under mild reaction conditions.