New routes to polyfunctionally substituted pyridine, pyridopyridine, quinoline, and pyridazine derivatives

The pyridine derivatives 4 and 10 are obtained by condensing β‐aminocrotononitrile (1a) with malononitrile. Compound 4 affords the pyridylpyridazine 7 on coupling with aryldiazonium salts. The reaction of 1a with cyanothioacetamide affords 12 which affords the thieno[2,3‐b]pyridine 13 on treatment with phenacylbromide, and pyrido[2,3‐b]pyridine 15 on treatment with benzylidenemalononitrile (14). A variety of new pyridines, cyclohexadiene, and pyridopyridine derivatives were obtained from reaction of 2‐amino‐1‐propene‐1,1,3‐tricarbonitrille (1b) and diethyl 3‐amino‐2‐cyanopent‐2‐enedioate (1c) with Michael‐systems. Reaction of 1b with acrylonitrile afforded an acyclic diadduct 25 which could be cyclized to the aminoquinoline 26.