Studies on vitamin D and related compounds XVII: The photo‐formation of lumisterol

Abstract

Abstract A further investigation has been made of the pathway of the photo‐formation of lumisterol, which had remained doubtful after the previous analyses of irradiation mixtures, in which lumisterol was determined indirectly 3 . Experiments using tachysterol 3 ‐7‐ 3 H reveal that lumisterol is not formed directly from tachysterol to a significant extent. Thin layer chromatograms of mixtures obtained after various times of irradiation starting with solutions of pre‐calciferol 3 and tachysterol 3 indicate the direct formation of lumisterol 3 from precalciferol 3 . The modified scheme of interrelationships between pro‐ and pre‐vitamin D, lumisterol and tachysterol is essentially the one originally postulated by Velluz, Amiard and Goffinet 11 . The question whether ergosterol and tachysterol yield other photo‐products besides precalciferol remains to be investigated.