title: 3,28-Diacet-oxy-29-bromo-betulin.
abstract: In the title mol-ecule, C(34)H(53)BrO(4), all the cyclo-hexane rings adopt chair conformations, while the cyclo-pentane ring adopts an envelope conformation. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into corrugated sheets parallel to the ab plane.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Ding
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Jing
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiu-Feng
authors.initials: XF
authors.lastname: Yan