Isoln from adrenal cortex: von Euw, Reichstein, Helv. Chim. Acta 24, 885 (1941); from corpus luteum: Butenandt, Mamoli, Ber. 68, 1847 (1935); Prelog, Meister, Helv. Chim. Acta 32, 2435 (1949); from human pregnancy urine: Lieberman et al., J. Biol. Chem. 172, 263 (1948); from human placenta: Pearlman, Cerceo, ibid. 194, 807 (1952). Prepn from 20-methyl-Δ20-allopregnen-3β-ol: Koechlin, Reichstein, Helv. Chim. Acta 27, 549 (1944); from pregnenolone: Mancera et al., J. Org. Chem. 16, 192 (1951); Pappas, Nace, J. Am. Chem. Soc. 81, 4556 (1959); by redn of allopregnane-3,20-dione with sodium borohydride: Mancera et al., ibid. 75, 1286 (1953); from progesterone 20-cycloethylene ketal: Sondheimer, Klibansky, Tetrahedron 5, 15 (1959).