Download citation
Download citation

link to html
The structure of the title steroid [alternative name: 3β,6β-diacet­oxy-5β-methyl-19-norcholest-9(10)-ene], C31H50O4, confirms the generally accepted mechanism for the rearrangement of a cholestan-5α-ol derivative reported a century ago by Westphalen. The methyl group at position 10 of the starting material migrates to position 5 in the steroidal nucleus, while a Δ9 bond is formed, as indicated by the C=C bond length of 1.347 (4) Å. The methyl transposition leaves the 5R configuration unchanged, with the methyl oriented towards the β face. During the rearrangement, the steroidal B ring experiences a conformational distortion from chair to envelope with the C atom at position 6 as the flap. In the title structure, the isopropyl group of the side chain is disordered over two positions, with occupancies of 0.733 (10) and 0.267 (10). The carbonyl O atom in the acetyl group at C3 is also disordered with an occupancy ratio of 0.62 (4):0.38 (4).

Download citation
Download citation

link to html
The title steroid, C34H50O6S, is an inter­mediate on the synthetic route between diosgenin and brassinosteroids, which possess the A ring modified with the 2α,3α-diol functionality. The polycyclic spiro­stan system has the expected conformation, with six-membered rings adopting chair forms and the five-membered rings envelope forms (flap atoms are the methine C atom in the C/D-ring junction and the spiro C atom connecting rings E and F). The 3β-tosyl­ate group is oriented in such a way that S=O bonds are engaged in inter­molecular hydrogen bonds with O—H and C—H donors. Chains of mol­ecules are formed along [100] via O—H...O hydrogen bonds, and secondary weak C—H...O inter­actions connect two neighbouring chains in the [001] direction.
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds