Synthesis and anti-microbial activity of some imidazo[1',2':5,6]pyrimido[4,5-c]pyridazines and related heterocycles

The synthesis of the title heterocycles was achieved using 3-amino-5,6-diphenylpyridazine-4-carbonitrile (4) as a starting material. This compound was converted into the corresponding 4-imidazolinyl derivative 5 which was then subjected to cyclization reactions to afford the title compounds.