V. V. Sreerama Murti

5∶6∶7∶8-hydroxyflavonols

SummaryA method of complete synthesis of 5∶6∶7∶8-hydroxy flavonols is described. It starts from ω∶3∶6-trimethoxy-2∶4-dihydroxy-acetophenone which is subjected to partial methylation (of the 4-hydroxyl group) and subsequently to persulphate oxidation. The product, 2∶5-dihydroxy-ω∶3∶4∶6-tetramethoxy-acetophenone is condensed with the anhydride and sodium salt of anisic acid and also of benzoic acid. The resulting 6-hydroxy-flavones yield on further methylation the fully methylated ethers of calycopteretin and 6∶8-dihydroxy-galangin and on demethylation, the free hydroxy-flavonols.

A note on the constitution of gossypitrin

SummaryGossypitrin is fully methylated by means of dimethyl sulphate and potassium carbonate in acetone medium. The pentamethyl gossypetin obtained by hydrolysis has been directly compared with a synthetic sample and mixed melting point taken. Its ethyl ether has also been made.