Substituted Benzopyranopyridine and Pyrimidine Ring Syntheses by the Ternary Condensation of Ethyl Cyanoacetate, Salicylaldehyde, and Certain Aldehydes in the Presence of Ammonium Acetate

Various 1-substituted benzopyranopyridines were readily prepared by the condensation of ethyl cyanoacetate and salicylaldehyde (or 3-methoxysalicylaldehyde) with aliphatic aldehydes (propion, n-butyl, n- and isovaleraldehyde) in the presence of ammonium acetate. On the other hand, condensation with aromatic aldehydes such as benzaldehyde and o-, m-, or p-substituted benzaldehydes gave 2-aryl-benzopyranopyrimidines.