A novel synthesis and molluscicidal activity of some functionally substituted pyridine, pyrido[3,2-c]pyridazine, and pyrido[3,2-c]pyridazino[2',3'-a]quinazoline derivatives

Ethyl benzoylacetate reacts with the malononitrile dimer to afford 4-amino-5-benzoyl-2-dicyano methyl-6-hydroxypyridine, which undergoes the coupling reaction with aromatic diazonium salts to afford azo derivatives. These azo derivatives could be cyclized into pyrido[3,2-c]pyridazine and pyrido[3,2-c]pyridazino[2',3'-a]quinazoline derivatives upon reflux in ethanolic NaOH, presumably via their hydrazo tautomers. The molluscicidal activity of these compounds was evaluated.