12α-Hy-droxy-3,27-dioxooleanano-28,13-lactone.

There are two independent mol-ecules in the asymmetric unit of the title compound, C(30)H(44)O(5). They comprise a triterpenoid skeleton of five six-membered rings and a five-membered lactone ring. The five six-membered rings are all trans-fused. In both independent mol-ecules the D rings adopt a slightly distorted half-chair conformation due the presence of the lactone ring while the other four six-membered rings all adopt chair conformations. The characteristic carbon-carbon double bond of the oleanoic skeleton is absent. Inter-molecular O-H⋯O hydrogen bonds between the hy-droxy and carbonyl groups occur in the crystal structure.