1-Deacetoxy-1-oxocaesalmin

The title compound, C24H30O7, is a diterpenoid isolated from the seeds ofCaesalpinia minax. It consists of two cyclohexane rings (AandB), one unsaturated six-membered ring (C) and one furan ring (D). The stereochemistry of the ring junctures isA/B transandB/C trans. RingsAandBhave normal chair conformations whileCadopts 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...Ocarbonylhydrogen bonds link the molecules into a chain structure extending along thea-axis direction.