title: 1-Deacet-oxy-1-oxocaesalmin.
abstract: The title compound, C24H30O7, is a diterpenoid isolated from the seeds of Caesalpinia minax. It consists of two cyclo-hexane 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⋯Ocarbon-yl hydrogen bonds link the mol-ecules into a chain structure extending along the a-axis direction.
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Juan
authors.initials: J
authors.lastname: Feng
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Jian-Long
authors.initials: JL
authors.lastname: Zhang
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Rong-Rong
authors.initials: RR
authors.lastname: Zhang
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Ruan
authors.affiliation: Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Ren-Wang
authors.initials: RW
authors.lastname: Jiang