59171-29-8Relevant academic research and scientific papers
STUDIES OF THE SELECTIVE O-ALKYLATION AND DEALKYLATION OF FLAVONOIDS. XII. A NEW, CONVENIENT METHOD FOR SYNTHESIZING 3,5-DIHYDROXY-6,7-DIMETHOXYFLAVONES FROM 3,5,6,7-TETRAMETHOXYFLAVONES
Horie, Tokunaru,Kawamura, Yasuhiko,Tsukayama, Masao,Yoshizaki, Shiro
, p. 1216 - 1220 (2007/10/02)
The 5-methoxy group on 3,5,6,7-tetramethoxyflavones and the 3-methoxy group on 3,6,7-trimethoxy-5-tosyloxy-flavones were selectively cleaved with anhydrous aluminum bromide in acetonitrile under controlled conditions without the cleavage of benzyloxy groups on the B ring.By the application of these reactions, seven 3,5-dihydroxy-6,7-dimethoxyflavones were easily synthesized from the corresponding 3,5,6,7-tetramethoxyflavones which were synthesized from 3,6-dihydroxy-2,4ω-trimethoxycetophenone by means of the Allan-Robinson reaction followed by methylation.Keywords: Allan-Robinson reaction ; selective demethylation; 3,5,6,7-tetramethoxyflavone; 5-hydroxy-3,6,7-trimethoxyflavone; 6-hydroxy-3,5,7-trimethoxyflavone; 5-tosyloxyflavone; 5,6-dihydroxy-3,7-dimethoxyflavone; 3,5-dihydroxy-6,7-dimethoxyflavone, 3,5-diacetoxy-6,7-dimethoxyflavone
