title: Epibisde-hydro-neotuberostemonine J.
abstract: The title compound, C22H29NO4, a stemona alkaloid, is composed of two lactone rings (A and E), a six-membered ring (B), a pyrrole ring (C) and a seven-membered ring (D). The five-membered rings A and E exhibit envelope conformations (C atoms as flaps) while ring C is planar. Ring B exhibits a twist-chair conformation due to fusion with pyrrole ring C while ring D adopts a chair conformation. The junction between rings A and B is cis. In the crystal, weak C-H⋯O inter-actions involving the two carbonyl groups, a methyl-ene and a methyl group give rise to a three-dimensional network.
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: Lu
authors.initials: L
authors.lastname: Jin
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: Hai-Yan
authors.initials: HY
authors.lastname: Tian
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People's Republic of China.
authors.forename: Paul Pui-Hay
authors.initials: PP
authors.lastname: But
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