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A high‐yield modification of the baker‐venkataraman rearrangement. Application to the synthesis of 5‐hydroxyflavone and 6,8‐dichloro‐5‐hydroxyflavone
Author(s) -
Looker J. H.,
Edman James R.,
Dappen J. I.
Publication year - 1964
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.5570010308
Subject(s) - chemistry , yield (engineering) , flavones , derivative (finance) , propane , organic chemistry , chromatography , materials science , economics , financial economics , metallurgy
A three‐step synthesis of 5‐hydroxyflavone in 80% yield from 2,6‐dihydroxyaceto‐phenone is described. The key step is a modification of the Baker‐Venkataraman rearrangement in which small amounts of water are deliberately introduced. Characterization of the primary rearrangement products, 1‐(2,6‐dinydroxyphenyl)‐3‐phenyl‐1,3‐propane‐dione, and 1‐(2‐benzoyloxy‐6‐hydroxyphenyl)‐3‐phenyl‐1,3‐propanedione, is reported. Application of the synthesis to 3,5‐dichloro‐2,6‐dihydroxyacetophenone gives a mixture of 6,8‐dichloro‐5‐hydroxyflavone and its 3‐benzoyl derivative. Infrared spectral data are presented for several intermediates and flavones, and indicate the utility of the previously described infrared spectral method for detecting 3‐aroylflavones.