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Photochemical Synthesis of 2,2′‐Biflavanones from Flavone
Author(s) -
Chen ArhHwang,
Kuo WeiBao,
Chen ChiaWen
Publication year - 2003
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200300017
Subject(s) - chemistry , triethylamine , flavanone , acetonitrile , benzene , molar ratio , amine gas treating , nitrobenzene , ethanol , photodissociation , methylene , medicinal chemistry , organic chemistry , photochemistry , catalysis , flavonoid , antioxidant
Photolysis of flavone ( 4 ) with the electron‐donating amines including triethylamine or 2‐(N,N‐dimethylamino)ethanol in acetonitrile, benzene or methylene dichloride can easily afford two hydrodimers of 2,2′‐biflavanone(racemate) ( 5a ) and 2,2′‐biflavanone(meso) ( 5b ) and one reductive product of flavanone ( 6 ). Their yields were dependent on the molar ratios of substrate to amine, the kinds of amines, the solvents used and the irradiation sources. Higher yields were afforded 2,2′‐biflavanone(racemate) ( 5a ), 2,2′‐biflavanone(meso) ( 5b ) and flavanone ( 6 ) (30.0%, 20.9% and 15.8%, respectively) in the reaction condition of 1/2 molar ratio of flavone ( 4 ) to triethylamine in acetontrile with fourteen hours of irradiation.