Studies on vitamin D and related compounds X. Preparation and properties of cis-isotachysterol2†

The photochemical conversion of isotachysterol2 (in ether) has been studied; the effects of wave-length and time of irradiation on the composition of the irradiation mixture are discussed. On chromatography of the crude irradiation product a compound was obtained in a pure, non-crystalline form. The compound did not show antirachitic activity. The ultra-violet and infra-red absorption spectra, the iodine-catalysed quantitative conversion to isotachysterol2, the behaviour on heating in solution and the very low reactivity towards maleic anhydride led to the conclusion that the compound is the Δ6,7-cis isomer of isotachysterol2, i.e. 9,10-secoergosta-5(10),6-cis, 8(14), 22-tetraen-3β-ol.