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Benzopyrans. Part 42 . Reactions of 4‐Oxo‐4 H ‐1‐benzopyran‐3‐carbaldehyde with some active methylene compounds in the presence of ammonia
Author(s) -
Ghosh Chandra Kanta,
Ray Anirban,
Patra Amarendra
Publication year - 2001
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570380632
Subject(s) - chemistry , acetylacetone , diethyl malonate , ethyl acetoacetate , ammonia , pyridine , methylene , medicinal chemistry , aldehyde , organic chemistry , catalysis
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.