Benzopyrans.: Part 42.: Reactions of 4-oxo-4H-1-benzopyran-3-carbaldehyde with some active methylene compounds in the presence of ammonia

The title aldehyde 1 in the presence of ammonia gives the pyridine derivatives 9-11 respectively with acetylacetone, diethyl malonate and ethyl cyanoacetate, and ethyl (or methyl)-1-benzopyrano[4,3-b]pyridine-3-carboxylate 22 (or 23) with ethyl (or methyl) acetoacetate. Acetylacetone pretreated with ammonia condenses with 1 giving the fused pyridine 24. Ammonia converts the ester 6 to the pyridine 13 or 14. Chromic acid oxidation of 22 and 23 affords the coumarinopyridines 25 and 26, respectively.