Nitriles in Heterocyclic Synthesis. The Reaction of Polyhydric Naphthalenes, 4-Methylcoumarin-3-carbonitrile, and Alkylidenemalononitrile with Methylenemalononitrile

Abstract 2-Naphthol and naphthalenediols react with methylenemalononitrile, generated in situ from reaction of formaldehyde and malononitrile, to yield naphthopyrans and naphthodipyrans. 5-Hydroxynaphtho[2,1-b]pyrans reacted further with methylenemalononitrile to yield naphthodipyrans. The reaction of methylenemalononitrile with 4-methylcoumarin-3-carbonitrile afforded benzopyrano[4,3-h]quinoline. 6-Cyanomethyl-3-pyridinecarbonitriles, prepared via reacting 1-arylethylidenemalononitriles with malononitrile, afforded 4H-quinolizines on treatment with methylenemalononitrile.