Ruff and Reichstein1 have described a pregnan-7-ol and a pregnan-12-ol prepared by Wolff–Kishner reduction of acetoxypregnane ketones. They state that these two substances are probably the 7α- and 12α-hydroxy compounds; but since epimerization during Wolff–Kishner reduction is not excluded, they name them provisionally ‘7ξ’ and ‘12ξ’2. The molecular rotations of pregnan-7ξ-ol and of pregnan-12ξ-ol and their derivatives show that the two new compounds are indeed 7α and 12α.
Ruff, A., and Reichstein, T., Helv. chim. Acta, 34, 70 (1951).
The letter ‘ξ’ is used to indicate that the configuration of the substituent is unknown. Cf. “Proposals for Steroid Nomenclature” made by a conference at the CIBA Foundation, London. Chem. and Indust., p. SN1 (June 23, 1951).
Barton, D. H. R., and Klyne, W., Chem. and Indust., 755 (1948).
Barton, D. H. R., J. Chem. Soc., 813 (1945).