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

✍ Scribed by Chandra Kanta Ghosh; Anirban Ray; Amarendra Patra

Publisher: Journal of Heterocyclic Chemistry
Year: 2001
Tongue: English
Weight: 51 KB
Volume: 38
Category: Article
ISSN: 0022-152X
DOI: 10.1002/jhet.5570380632

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✦ Synopsis

Abstract

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)‐l‐benzopyrano[4,3‐b]pyri‐dine‐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.

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