A steroid structure which refutes the isolation of C(17)-C(20) rotational isomers

Abstract Isolation of two C(17)-C(20) rotamers of 20-methyl-20-(2-hydroxy-ethoxy)-5-pregnene-3β, 17α-diol has been reported. X-Ray analysis of a diacetate derivative of one of the “rotamers” shows that the actual structure is 3β-acetoxy-17aα-(2-acetoxyethoxy)-17α,17aβ-dimethyl-D-homo-5-androsten-17β-ol (C 28 H 44 O 6 ). Thus, although this investigation refutes the existence of C(17)-C(20) rotamers, it suggests a possible new pathway for D-homo steroid synthesis.