| Summary: | The title compound, C27H34O5 {systematic name: (4aR,5R,6R,6aS,7R,11aS,11bR)-4a,6-dihydroxy-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-5-yl benzoate}, is a cassane furanoditerpene, which was isolated from the roots of Caesalpinia pulcherrima. The three cyclohexane rings are trans fused: two of these are in chair conformations with the third in a twisted half-chair conformation, whereas the furan ring is almost planar (r.m.s. deviation = 0.003 Å). An intramolecular C—H...O interaction generates an S(6) ring. The absolute configurations of the stereogenic centres at positions 4a, 5, 6, 6a, 7, 11a and 11b are R, R, R, S, R, S and R, respectively. In the crystal, molecules are linked into infinite chains along [010] by O—H...O hydrogen bonds. C...O [3.306 (2)–3.347 (2) Å] short contacts and C—H...π interactions also occur.
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