18-Norandrosta-8,11,13-trienes. Part III. 1-Amino-derivatives
The syntheses of 1α-amino-17,17-dimethyl-18-nor-5α-androsta-8,11,13-triene (9e) and its N-methyl derivatives are described. Bromination–dehydrobromination of 1α-benzolyoxy-17,17-dimethyl-18-nor-5α-androst-13-ene (6b) gave 1α-benzoyloxy-17,17-dimethyl-18-nor-5α-androsta-7,13-diene (7), which on subsequent bromination–dehydrobromination and saponification gave 17,17-dimethyl-18-nor-5α-androsta-8,11,13-trien-1α-ol (9a). This was converted into the 1α-amino-derivatives via the ketone (8a). Reduction of 17,17-dimethyl-18-nor-5α-androsta-8,11,13-trien-1-one (8a) with sodium in alcohol gave a mixture of the 1α- and 1β-alcohols (9a) and (10), whereas reduction with lithium aluminium hydride gave the 1α-epimer (9a) stereospecifically. Both methods of reduction when applied to the corresponding 1-oxime (8b) gave entirely the 1α-amine (9e), a result which is explained in terms of steric interaction between positions 1 and 11. The corresponding 1β-amines could not be prepared.