An Improved Synthesis of la, 3 p-Dihydroxycholesta- 5,7-Diene

Abstract

The chemically synthesized la-hydroxyvitamin D la-OH-D₃, is an extremely active analog of lα dihydroxyvitamin D₃(1,25-(OH)₂-D₃ la)^{2,3,4,0,5,0,6,7,8} the hormonally active form of vitamin D₃, lc. A key The chemically synthesized la-hydroxyvitamin kQ),intermediate in the synthesis of la-OH-D is the provitamin diacetate z. thetic studies it was necessary to develop a more efficient synthesis of the provitamin diol 4b. from which lb. can be rapidly obtained by means of photolysis and thermolysis.