Improved, Rapid and Efficient Synthesis of Polymethoxyflavones under Microwave Irradiation and Their Inhibitory Effects on Melanogenesis
作者:Masao Tsukayama、Yasuhiko Kawamura、Takaaki Ishizuka、Shinji Hayashi、Fumihito Torii
DOI:10.3987/com-03-9891
日期:——
The microwave-assisted methylation of 2,5-dihydroxy-1,3-dimethoxybenzene with (CH3O)(2)SO2 for 5 min gave easily 1,2,3,5-tetramethoxybenzene, which was converted into pentamethoxybenzene. The microwave-assisted Friedel-Crafts acylation of pentamethoxybenzene in the presence of In(CF3SO3)(3) gave pentamethoxyacetophenone for 15 min under solvent-free conditions in high yield. The microwave-assisted cyclization reaction of the diketones, which were synthesized from the acetophenone via three steps under microwave irradiation, gave the desired polymethoxyflavones for 1.5-3 min in high yields. The polymethoxyflavones showed inhibitory effects on melanogenesis in a human melanoma.