Steroids of pregnant mares' urine. IV. Fractionation of the neutral steroids. Examination of some non-ketonic fractions.

Previous papers in this series (Klyne, Schachter & Marrian, 1948; Klyne, 1948; Paterson & Klyne, 1948) have described the isolation from pregnant mares' urine of 5a-pregn-16-en-3,B-ol-20-one, uranediol and 5a-pregnane-3,B-ol-20-one as their sulphuric acid esters. This paper describes the fractionation of the neutral steroids of pregnant mares' urine and the detailed examination of some non-ketonic fractions. Most previous workers have concentrated their attention on the ketonic fractions (see, for example, Heard & McKay, 1939; Heard & Hofmann, 1940, 1941; Oppenauer, 1941; Prelog & Fiihrer, 1945; the last-mentioned paper gives full references to earlier work). Marker and his colleagues in the years 1937-9 (see references on p. 707) dealt extensively with both ketonic and non-ketonic fractions, but their work was carried out with commercial urine extracts which had been so harshly treated that some ofthe compounds isolated may have been artifacts. Bauld & Heard (1940) have carried out a brief examination of the non-ketonic steroid fraction. Preliminary accounts ofparts ofthe present work have already been given (Klyne & Paterson, 1948; Brooks, Klyne & Miller, 1951 a). The identification of uranediol as a D-homosteroid has been described elsewhere (Klyne, 1950). Nomenclature follows the rules proposed by a conference at the CIBA Foundation, London, and published in J. chem. Soc. (1951), p. 3526. Steroid rings are distinguished as A, B, C and D (italic capital letters) and not A, B, c and D (Roman small capitals) as shown in these rules. Small capitals are undesirable since D (and L) are used for another purpose in designating configurations relative to glyceraldehyde or serine (cf. Biochem. J. 1948, 42, 1). Prof. T. Reichstein draws attention to this point in the German version of the steroid nomenclature rules (Helv, chim. Acta, 1951, 34, 1680).