Synthesis of neoflavonoids: 4-(4'-methoxyphenyl)3,4-dihydrocoumarins

The neoflavonoids 7-hydroxy-5-methyl-4-(4'-methoxyphenyl)-3,4-dihydrocumarin (1), 5-hydroxy-7-methyl-4-(4'-methoxyphenyl)-3,4-dihydrocoumarin (2), 5-methyl-7-O-coumaroyl-4-(4'methoxyphenyl)-3,4-dihydrocoumarin (3), 5-hydroxy-4-(4'-methoxyphenyl)-alpha-pirano-(6 '',5 '':7,8)-3,4-dihydrocoumarin (7), and 7-pentadecyl-4-(4'-methoxyphenyl)-3,4-dihydrocoumarin (8) were synthesized via the AlCl3-catalyzed condensation of 4-methoxycinnamic acid chloride with orcinol, 5,7-dihydroxycoumarin and hydrogenated cardanol. The compounds were characterized on the basis of their H-1- and C-13-NMR spectroscopic properties, including nOe difference spectroscopy.