Concerning the structure of 3 beta-benzoyloxy-5 beta-cholesta-8,14-diene, a major byproduct in the chemical synthesis of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one

The X-ray crystal structure of 3 beta-(p-bromobenzoyloxy)-5 beta-cholesta-8,14-diene (space group P21, a = 10.698 A, b = 9.487 A, c = 15.024 A, beta = 96.05 degrees, Z = 2) was determined by the heavy atom method and refined to R = 0.075. This heavy atom derivative was synthesized from 5 beta-cholesta-8,14-diene-3 beta-ol, the benzoate ester of which was previously shown to be the major byproduct in the low-temperature isomerization of 7-dehydrocholesteryl benzoate in HCl/chloroform. The work presented here establishes unequivocally that the configuration of this isomerization byproduct at C-5 is 5 beta-H and that the configuration at C-17 was unchanged.