Betulin 3,28-di-O-tosyl­ate

The title compound, C(44)H(62)O(6)S(2) {systematic name: (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-5a,5b,8,8,11a-penta­methyl-1-(prop-1-en-2-yl)-3a-[(tos­yloxy)meth­yl]icosa­hydro-1H-cyclo­penta­[a]chrysen-9-yl 4-methyl­benzene­sulfonate}, was obtained by tosyl­ation of naturally occurring betulin. All the cyclo­hexane rings adopt chair conformations and the cyclo­pentane ring adopts a twisted envelope conformation, with the C atom bearing the tosyl­methyl substituent forming the flap. In the crystal, mol­ecules form a three-dimensional network through multiple weak C—H⋯O hydrogen bonds.