1: pyridine / 20 °C 2: HBr; acetic acid / 1.5 h / 20 °C 3: 1.34 g / 20 °C View Scheme

T=20°C; Kochetkov method;

toluene-4-sulfonic acid in acetonitrile T=20°C; 16 h;

toluene-4-sulfonic acid in acetonitrile T=20°C; 16 h; Yield given;

1: 86 percent / TsOH*H2O / acetonitrile / 16 h / 20 °C 2: 1) MS4A, 2) nitrosyl tetrafluoroborate / 1) CH2Cl2, 20 deg C, 45 min, 2) 20 deg C, 1 h 3: 81 percent / trifluoroacetic acid / CHCl3; H2O / 0.67 h 4: hydrazine hydrate / aq. ethanol / 10 h / Heating 5: methanol; H2O / 17 h / 20 °C View Scheme

1: p-TsOH / acetonitrile / 0.33 h 2: NaH / dimethylformamide / 20 °C 3: methyl orange; NaCNBH3; HCl / tetrahydrofuran; diethyl ether View Scheme

1: 85 percent / p-toluenesulphonic acid / acetonitrile 2: 86 percent / sodium hydride / 1,2-dimethoxy-ethane 3: 95 percent / molecular sieves, sodium cyanoborohydride, HCl / tetrahydrofuran; diethyl ether / 1 h / Ambient temperature 4: 46 percent / collidine, silver triflate / nitromethane / 1.) -25 deg C, 4 h; 2.) rt, overnight 5: 1.) hydrazine hydrate / 1.) 95percent aqueous ethanol, reflux, 30 min; 2.) pyridine, rt, overnight 6: 87 percent / hydrogen / palladium-on-carbon / methanol / 16 h View Scheme

1: 85 percent / p-toluenesulphonic acid / acetonitrile 2: 86 percent / sodium hydride / 1,2-dimethoxy-ethane 3: 95 percent / molecular sieves, sodium cyanoborohydride, HCl / tetrahydrofuran; diethyl ether / 1 h / Ambient temperature 4: 46 percent / collidine, silver triflate / nitromethane / 1.) -25 deg C, 4 h; 2.) rt, overnight 5: 1.) hydrazine hydrate / 1.) 95percent aqueous ethanol, reflux, 30 min; 2.) pyridine, rt, overnight 6: 87 percent / hydrogen / palladium-on-carbon / methanol / 16 h 7: 65 percent / tetraethylammonium bromide, molecular sieves / CH2Cl2; dimethylformamide / 16 h / Ambient temperature 8: 1.) hydrogen; 2.) sodium methoxide / 1.) palladium-on-carbon / 1.) methanol, 16 h; 2.) methanol View Scheme

1: 85 percent / p-toluenesulphonic acid / acetonitrile 2: 86 percent / sodium hydride / 1,2-dimethoxy-ethane 3: 88 percent / 60percent aqueous acetic acid / 0.5 h / 100 °C 4: 42 percent / tetraethylammonium bromide, molecular sieves / CH2Cl2 / 6 h / Ambient temperature View Scheme

1: p-TsOH / acetonitrile / 0.33 h 2: NaH / dimethylformamide / 20 °C View Scheme