(6a R)-1-Hydroxy-2,2,6a,6b,9,9,12a-heptamethyl-10-(methylcarbonyloxy)perhydro-4-picenylmethyl acetate.

The title compound, C34H56O5, an oleanane triterpene, is a key intermediate in the synthetic route from betulin to 18(19)-oleanene triterpenoids. In the molecule, all bond lengths and angles are normal. The hydroxy groups are involved in intermolecular O—H...O hydrogen bonds, which link the molecules into zigzag chains running along the a axis. The crystal packing is further stabilized by weak intermolecular C—H...O hydrogen bonds. [ABSTRACT FROM AUTHOR]