1-Deacet­oxy-1-oxocaesalmin

The title compound, C₂₄H₃₀O₇, is a diterpenoid isolated from the seeds of Caesalpinia minax. It consists of two cyclo­hexane rings (A and B), one unsaturated six-membered ring (C) and one furan ring (D). The stereochemistry of the ring junctures is A/B trans and B/C trans. Rings A and B have normal chair conformations while C adopts a twisted half-chair conformation due to fusion to the furan ring which is planar [r.m.s. deviation = 0.0009 (2) Å]. In the crystal, hydroxyl O—H...O_carbon­yl hydrogen bonds link the mol­ecules into a chain structure extending along the a-axis direction.