Steroid analogues. Part 2. Synthesis of unsymmetrical bi(cycloalkylidene)s via vic-dinitro-compounds
Abstract
The light-catalysed reaction of 4,4-dinitrocyclohexanol (6) with the lithium salts of 4-substituted 1-nitrocyclohexanes [4-OBz (4), 4-CH2CO2Me (12), 4-CH2COMe (15), and 4-H (11)] gave 4′-substituted 4-hydroxy-1,1′-dinitro-1,1′-bicyclohexyls (16). Irradiation of the latter in the presence of sodium sulphide in dimethylformamide gave 4′-substituted 4-hydroxy-1,1′-bi(cyclohexylidene)s (17)–(21) in overall yields of 29–70%. Condensation of (±)-6β-methyl-3,3-dinitro-trans-bicyclo[4.3.0]nonan-7β-ol (31) with the lithium salt of 4-benzoyloxy-1-nitrocyclohexane (4) gave in 12% yield a 1 : 1 mixture of the epimeric (±)-3ξ,17β-dihydroxy-6,7-dinor-5,8-secoestr-9-enes (33).