Novel oligorhamnosides from the stem bark of Cleistopholis glauca

A reinvestigation of the stem bark of Cleistopholis glauca yielded 14 compounds, of which seven were either novel or had not been previously reported from this species. These were identified as the farnesane sesquiterpene methyl-(2E,6E)-10-oxo-3,7,11-trimethyl-dodeca-2,6-dienoate (1); the azaanthracene alkaloid cleistopholine (4); two partially acetylated oligorhamnoside derivatives, 1-O-dodecanyl-2,3,4-tri-O-acetyl-α-rhamnopyranosyl-(1→3)-2,4-di-O-acetyl-α-rhamnopyranosyl-(1→3)-4-O-acetyl-α-rhamnopyranosyl-(1→4)-α-rhamnopyranoside (6) and 1-O-dodecanyl-2,4-di-O-acetyl-α-rhamnopyranosyl-(1→3)-2,4-di-O-acetyl-α-rhamnopyranosyl-(1→3)-4-O-acetyl-α-rhamnopyranosyl-(1→4)-α-rhamnopyranoside (8), for which the trivial names cleistetroside-7 and cleistetroside-6 were assigned, respectively; the dihydrobenzofuran neolignan rel-(2α,3β)-7-O-methylcedrusin (12); and the flavonoids dihydroquercetin (13) and quercetin (14). Structure assignments of all compounds were established by spectroscopic methods and comparison with published data. The chemosystematic significance of the occurrence of the isolated components is mentioned. Compounds 1, 6, and 8 are novel natural products.