Studies on organic fluorine compounds. LII. Synthesis and biological activity of 26,26,26,27,27-pentafluoro-1.ALPHA.-hydroxy-27-methoxyvitamin D3.

Abstract

Replacement of one fluorine atom of the hexafluorocholesterol derivative (4) with a methoxyl group took place during the saponification of the acetyl groups of 4 with methanolic potassium hydroxide to give the pentafluoromethoxy compound (5), which was converted to the corresponding 1.alpha.-hydroxyvitamin D3 form (6). The pentafluoromethoxy compound (6) was found to be about three times more potent than 1.alpha.-hydroxyvitamin D3 in displacing radio-labeled 1,25-dihydroxyvitamin D3 from the chick intestinal receptor, whereas the activity of 6 in response to bone calcium-mobilization in vitamin D-deficient rats was slightly lower than that of 1.alpha.-hydroxyvitamin D3.