A Novel Approach to the Synthesis of 1-Substituted-3,6-diaryl-imidazo[1,5-b]pyridazines

Abstract

A simple and efficient procedure for the preparation a new type of 1-substituted-3,6-diaryl-imidazo[1,5-b]pyridazines was described. This synthesis was carried out by the following three steps: Aryl methyl ketone 3 was condensed with 1-amino-2-subsatiuted-4-arylimidazole 2 in ethanol with catalytic glacial acetic acid to afford enamines 4 a–k. Treatment with t-butoxybis(dimethylamino)methane in DME at room temperature gave enamine (5a-k) which was cyclized to compound (1a–k) in 84–96% yield in trifluoroacetic acid.