Convenient method for the synthesis of phthalazinones via carbonylation of 2-bromobenzaldehyde using Co2(CO)8 as a CO source

A simple one-pot synthesis of phthalazinones by the condensation and intra-molecular carbonylative cyclization of 2-bromobenzaldehydes with hydrazines is reported. This method utilizes solid Co2(CO)8 as carbonyl source making it readily accessible in small-scale laboratory applications.