Synthesis of new pyrrolo[3,4-c]isoxazole, pyrrolo[2,3-d]-[1,2,3]triazole, triazolo[4,5-c]pyridazine, and dipyrrolo[3,2-b:3′,4′-d]pyran derivatives

New pyrrolo[3,4-c]isoxazole derivatives were synthesized from the key intermediates 4-cyanopyrrolidin-3-ones in two steps. Pyrrolo[2,3-d][1,2,3] triazoles and triazolo[4,5-c]pyridazine were obtained from 2-arylhydrazono-4- cyano-1-(4′-methoxyphenyl)-3-oxopyrrolidines by refluxing with Phenylhydrazine in either ethanol or glacial acetic acid. Aldol self-condensation of 1-aryl-4-cyanopyrrolidin-3-ones afforded dipyrrolo[3,2-b:3′,4′-d]pyran derivatives.