Studies on the Constituents of the Roots of Cassia torosa. II. : The Structures of Two Dimeric Tetrahydroanthracenes

Abstract

Two new dimeric tetrahydroanthracene derivatives, torosaols I (1) and II (2), were isolated from the fresh roots of Cassia torosa Cav. along with pinselin, questin, 7-methyltorosachrysone, singueanol-I, germichrysone, germitorosone, methylgermitorosone, and phlegmacins A₂ and B₂. The structures of compounds 1 and 2 were established as 3, 3', 4, 4'-tetrahydro-2, 3, 3', 8, 8', 9, 9'-heptahydroxy-6, 6'-dimethoxy-3, 3', 7, 7'-tetramethyl-10, 10'-bi-1(2H)-anthracenone and 5-[3', 4'-dihydro-3', 8', 9'-trihydroxy-6'-methoxy-3', 7'-dimethyl-1' (2'H)-anthracenon-10'-yl]-3, 4-dihydro-9, 10-dihydroxy-3-hydroxymethyl-7-methoxy-3, 8-dimethyl-1H-naphtho[2, 3-c]pyran-1-one, respectively, on the basis of spectral evidence.