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Pechmann reaction of 4‐hydroxycoumarins and thiocoumarins with cyclohexanone and ethyl cyclopentanone‐2‐carboxylates
Author(s) -
Merchant J. R.,
Koshti N. M.,
Bakre K. M.
Publication year - 1981
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.5570180837
Subject(s) - chemistry , cyclopentanone , cyclohexanone , acetic anhydride , benzopyran , dehydrogenation , isocoumarins , organic chemistry , derivative (finance) , isocoumarin , hydrolysis , bicyclic molecule , catalysis , financial economics , economics
The Pechmann reaction of 4‐hydroxycoumarins with cyclohexanone and ethyl cyclopentanone‐2‐carboxylates affords 1,2,3,4‐tetrahydro[2]benzopyrano[4,3‐ c ][1]benzopyran‐5,12‐diones and cyclopenta[3′,4′]pyrano‐[3,2‐ c ][1]benzopyran‐4,11‐diones. Dehydrogenation of the former yields [2]benzopyrano[4,3‐c][1]benzopyran‐5,12‐diones. Alkaline hydrolysis of a typical compound Va affords 2‐hydroxy‐2′‐carboxydeoxybenzoin which on boiling with acetic anhydride gives an isocoumarin derivative.