3α-Hy-droxy-tirucalla-8,24-dien-21-oic acid.

The title compound, C(30)H(48)O(3), a triterpene isolated from the resin of canarium schweinfurthiiand, is an isomer of the previously reported triterpene 3α-hy-droxy-tirucalla-7,24-dien-21-oic acid [Mora et al. (2001 ▶). Acta Cryst. C57, 638-640], which crystallizes in the same trigonal space group. The title mol-ecule consists of four fused rings having chair, half-chair, half-chair and envelope conformations for rings A, B, C and D, respectively (steroid labelling). An intra-molecular C-H⋯O hydrogen bond generates an S(7) ring. In the crystal, mol-ecules are linked by O-H⋯O and C-H⋯O inter-actions, forming (001) sheets.