A new quassinoid isolated from Picrolemma pseudocoffea

Abstract

The rings in 15β-(acetyloxy)-13,20-epoxy-11β,12α-dihydroxy- 16,2'-dioxo-2,2'-olide-picras-1(1'),2-dien21-oic acid methyl ester, C 25 H 28 O 11 .H 2 O (systematic name: methyl 4β-acetyloxy-14β,15α-dihydroxy8α,12β-dimethyl-5,11-dioxo-3,3a,4,5,6a,7,7a,8,12b,13-decahydro-3,13-ethano-1H,11H-furo[3,4-c]furo-[3',2':5,6]naphtho[2,3-b]pyran-3-carboxylate monohydrate) have all-trans ring fusion. The carbomethoxy and the acetyloxy moieties are each in a pseudo-equatorial position and the hydroxyl groups are trans to each other