Hydroxylation with ozone on silica gel. The synthesis of 1. alpha., 25-dihydroxyvitamin D3 Academic Article uri icon

abstract

  • Summary: A convenient synthesis of la, 25-dihydroxyvitamin D3, the natural calcium regulating hormone, based on a regioselective C25-hydroxylation of la, 3@-diacetoxy-6@, 7a-di-bromocholestane by means of ozone absorbed on silica gel, is reported. Sir: As a further development of our studies on the functionalization of unactivated carbon atoms, l we report on the utilization of the recently published method of dry ozonation2 for a relatively simple synthesis of the calcium regulating hormone, viz., the la, 25-dihydroxyvitamin D3 (lbh3 The key step in this synthesis is the highly regioselective Cas-hydroxylation of a tetrasubstituted cholestane derivative, the dibromide 2a, which is an intermediate in the preparation of a physiological useful substitute of lb, viz., the la-hydroxyvitamin D34 (la). We obtained this dibromide intermediate, 2a, in a five-step synthesis from cholesterol, by the

publication date

  • August 1, 1976