Conformational analysis-LII. The conformation of ring a in 5β-3-ketosteroids

Article abstract of DOI:10.1016/0040-4020(67)85079-8

5β-Cholane-3,12-dione has been synthesized, and its dipole moment measured in benzene solution. The value of 4·49 D shows that ring A is in the chair form to within the limits of experimental measurement, which indicates that the earlier interpretation of the dipole moment of 5β-androstan-3,17-dione in terms of an equilibrium mixture of boat and chair forms for ring A is improbable, and that the later compound is more likely to have a deformation present in ring D.