title: Betulin 3,28-di-O-tosyl-ate.
abstract: The title compound, C44H62O6S2 {systematic name: (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-5a,5b,8,8,11a-penta-methyl-1-(prop-1-en-2-yl)-3a-[(tos-yloxy)meth-yl]icosa-hydro-1H-cyclo-penta-[a]chrysen-9-yl 4-methyl-benzene-sulfonate}, was obtained by tosyl-ation of naturally occurring betulin. All the cyclo-hexane rings adopt chair conformations and the cyclo-pentane ring adopts a twisted envelope conformation, with the C atom bearing the tosyl-methyl substituent forming the flap. In the crystal, mol-ecules form a three-dimensional network through multiple weak C-H⋯O hydrogen bonds.
authors.affiliation: Department of Material Science and Applied Chemistry, Riga Technical University, 3 P. Valdena Str., Riga LV-1007, Latvia.
authors.forename: Uldis
authors.initials: U
authors.lastname: Peipiņš
authors.affiliation: Department of Material Science and Applied Chemistry, Riga Technical University, 3 P. Valdena Str., Riga LV-1007, Latvia ; Ogre State Gymnasium, 14 Meza prosp., LV-5001, Ogre, Latvia.
authors.forename: Niks
authors.initials: N
authors.lastname: Freimanis
authors.affiliation: Latvian Institute of Organic Synthesis, 21 Aizkraukles Str., Riga LV-1006, Latvia.
authors.forename: Dmitrijs
authors.initials: D
authors.lastname: Stepanovs
authors.affiliation: Latvian Institute of Organic Synthesis, 21 Aizkraukles Str., Riga LV-1006, Latvia.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Mishnev
authors.affiliation: Department of Material Science and Applied Chemistry, Riga Technical University, 3 P. Valdena Str., Riga LV-1007, Latvia.
authors.forename: Māris
authors.initials: M
authors.lastname: Turks
keywords: betulin 3,28-di-O-tosyl­ate; crystal structure; hydrogen bonding; natural product