SYNTHESIS OF SOME ANALOGS OF CYTISINE - UNUSUAL REDUCTION PATHWAYS FOR TERTIARY NITRO-GROUPS IN STERICALLY CONSTRAINED MOLECULES

The naphthalene derivative 4 was converted into the dinitro compound 5 by a 'double Mannich' reaction. Reduction of the compound 5 with trib utylstannane gave the hydroxylamines 6 and 7 in low yield, Treatment o f 5 with methanethiolate in DMSO gave the sulfides 8, 9 and/or 10 in v arying ratios, depending on the reaction conditions. Raney nickel redu ction of 10 gave the cytisine analogue 1. Similarly the dinitroquinoli ne 13 was converted into the dinitro compound 14, Treatment of 14 with sodium methanethiolate gave a mixture of the sulfides 15-17. Reductio n of the compounds 16 and 17 with Raney nickel gave the pyridoazocine 2. The mechanisms of formation of the hydroxylamines 6 and 7 and the s ulfides 8-10, 15-17 are discussed.