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Chemical Transformations of Some Coumarin‐Enaminoester Adducts
Author(s) -
Ivanov Ivo C.,
Raev Lyubomir D.
Publication year - 1987
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.198719870880
Subject(s) - chemistry , adduct , coumarin , yield (engineering) , acetic anhydride , acetic acid , cyclohexenone , base (topology) , organic chemistry , medicinal chemistry , stereochemistry , catalysis , mathematical analysis , materials science , mathematics , metallurgy
The adducts 4a, b , initially formed from the coumarins 1a, b and ene‐diamino ester 2 , have been converted into substituted benzopyrano[3,4‐ c ]pyridines 5, 7 , and 8 . The tricyclic compound 7 is obtained by base‐catalyzed rearrangement of the decarboxylated adduct 3 . The possible intermediate of this reaction is trapped as an acetate 6 upon treatment of 3 with acetic anhydride. The adduct 10 (from the acid 1a and ethyl 3‐aminocrotonate) decarboxylates spontaneously to give the dihydrocoumarin 11 which rearranges further to yield the 2‐pyridinone 12 . The cyclohexenone 13 is isolated as byproduct.