Antirachitic sulfonation of some steroids.

A few sterols, some derivatives, and certain steroid materials have been transformed chemically, by heating with suitable reagents (l-4), to products having antirachitic activity. This activating reaction1 involves heating an appropriate substrate in acetic acid solution with an efficient sulfonating reagent under anhydrous conditions for a number of hours. At the termination of the reaction time, the acetic acid is removed by vacuum distillation. The antirachitic material is contained in the residue. Among the various sulfonating reagents tried in acetic acid solution, sulfuric acid-acetic anhydride or chlorosulfonic acid generally has produced residues having the greatest potencies when the substrate was either cholesterol or those derivatives of it which are unsaturated at carbon 5 and react positively to the Liebermann-Burchard blue to green color test (5). Since the appearance of the earlier reports referred to above, the procedure of antirachitic sulfonation has been variously modified and applied to some of the oxidized cholesterol derivatives in addition to cholesterol and to certain steroid-containing materials. This communication presents the results of some of these studies.