Conformational studies. Part 2. Synthesis of 17β-hydroxy-4,4-dimethyl-5α-androstan-3-one, and of the 19-nor-analogue
Abstract
Prepared from 17β-hydroxy-5α-androstan-3-one by C-4 methylation of 17β-(tetrahydropyran-2-yloxy)-2,2-trimethylenedithio-5α-androstan-3-one, 17β-hydroxy-4,4,dimethyl-5α-androstan-3-one (1; R1= Me, R2= H), exhibited a negative o.r.d. curve, and was identical with the hydrogenation product of 17β-hydroxy-4,4-dimethyl-androst-5-en-3-one (2; R1= Me, R2= H). 17β-Hydroxy-4,4-dimethyl-19-nor-5α-androstan-3-one (1; R1= R2= H) was similarly synthesised from 17β-hydroxy-19-nor-5α-androstan-3-one and also had a negntive o.r.d. curve. However, contrary to previous reports, hydrogenation of 17β-hydroxy-4,4-dimethyl-19-nor-androst-5-en-3-one (2; R1= R2= H) did not furnish the androstane (1; R1= R2= H) but a mixture of (1; R1= R2= H) and the 5β-diastereoisomer which was difficult to separate; both these products exhibit negative o.r.d. curves. The physical constants of various cognate derivatives of (1; R1= R2= H), reported values of which are probably those of mixtures, have been clarified.
B-Nortestosterone has been converted into 17β-hydroxy-4,4-dimethyl-B-nor-5α-androstan-3-one. The preparation of various steroidal 2-butylthiomethylene-3-ones is reported.