Isolation and characterization of new diacyl 6-O-.ALPHA.-L-rhamnopyranosylcatalpols from the leaves of Premna japonica Miq.

Abstract

Two diacyl rhamnopyranosylcatalpols were isolated from the leaves of Premna japonica. The structures of the compounds were determined to be 6-O-α-L-(2"-O-isoferuloyl, 4"-O-acetyl)rhamnopyranosylcatalpol and 6-O-α-L-(3"-O-isoferuloyl, 4"-O-acetyl)rhamnopyranosylcatalpol. The locations of acyl moieties were determined by long-range proton selective decoupling experiments and by partial alkaline hydrolysis.