(20S)-20-Methyl-5α-pregnan-21-oic acid

Purification Methods

Bisnorcholanic acid crystallises from EtOH (-form), or acetic acid (all forms). The -form has [] 20D -7.5o (c 0.8, EtOH), and its ethyl ester has m 106-107o; the -form has [] D +23.3o (c 0.86, EtOH), and its ethyl ester is an oil; the  -form has [] D 0o, and its ethyl ester has m 82-83o; the -form has [] D +31.7o (c 0.76, EtOH), and its methyl ester has m 99o; the -form has [ ] 20D +14.3o (c 0.8, EtOH), and its methyl ester has m 117o. [Wieland et al. Hoppe Seyler’s Z Physiol Chem 161 80 1926, Beilstein 9 III 2650.]