title: 15-Hydroxy-ethyl-19-isopropyl-5,9-dimethyl-14,16-dioxo-15-aza-penta-cyclo-[10.5.2.0.0.0]nona-dec-18-ene-5-carboxylic acid.
abstract: The title compound, C(26)H(37)NO(5), which was synthesized from monoethano-lamine and maleopimaric acid, consists of two fused and unbridged cyclo-hexane rings. They form a trans ring junction with a chair conformation. The two methyl groups are in axial positions. In the crystal, inter-molecular O-H⋯O hydrogen bonds link adjacent mol-ecules into a layer structure. Two C-H⋯O interactions are also present.
authors.affiliation: Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Nanjing 210042, People's Republic of China.
authors.forename: Xu
authors.initials: X
authors.lastname: Xu
authors.forename: Zhan-Qian
authors.initials: ZQ
authors.lastname: Song
authors.forename: Shi-Bin
authors.initials: SB
authors.lastname: Shang
authors.forename: Hong-Xiao
authors.initials: HX
authors.lastname: Wang
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Rao