Anti-ulcer effect of isoprenyl flavonoids. III. Synthesis and anti-ulcer activity of metabolites of 2'-carboxymethoxy-4,4'-bis(3-methyl-2-butenyloxy)chalcone.

Five dihydrochalcone derivatives, 2'-carboxymethoxy-4, 4'-bis (3-methyl-2-butenyloxy) dihydrochalcone (M-6-b), 2', 4-bis (carboxymethoxy)-4'-(3-methyl-2-butenyloxy) dihydrochalcone (M-2), 2', 4-bis (carboxymethoxy)-4'-(3-carboxy-2-butenyloxy) dihydrochalcone (M-1-a), 2', 4-bis (carboxymethoxy)-4'-(3-hydroxymethyl-2-butenyloxy) dihydrochalcone (M-1-b), and 2'-carboxymethoxy-4-hydroxy-4'-(3-methyl-2-butenyloxy) dihydrochalcone (M-4-b), which are the main metabolites in rats of a new anti-ulcer drug "sofalcone"(2'-carboxymethoxy-4, 4'-bis (3-methyl-2-butenyloxy) chalcone) were synthesized and the anti-ulcer activities of the major metabolites in humans, M-6-b, M-2, and M-1-a, were examined by Shay's and Takagi's methods and also by the use of rats with histamine-induced ulcer. The most active compound was M-6-b, which showed activity equal to or slightly weaker than that of sofalcone.