sulfuric acid 18 h; Ambient temperature;

1: 74 percent / sulfur, Et3N / dimethylformamide / 3 h / 60 - 70 °C 2: 30 g / KOH, water / methanol / 2 h / Heating 3: 45 percent / H2SO4 / 18 h / Ambient temperature View Scheme

1: 74 percent / sulfur, Et3N / dimethylformamide / 3 h / 60 - 70 °C 2: 30 g / KOH, water / methanol / 2 h / Heating 3: 45 percent / H2SO4 / 18 h / Ambient temperature View Scheme

1: 30 g / KOH, water / methanol / 2 h / Heating 2: 45 percent / H2SO4 / 18 h / Ambient temperature View Scheme

1: 92 percent / aq. NaHCO3 / toluene / 1.5 h / 40 - 50 °C 2: 25 g / NH3 / ethyl acetate / 3 h / Ambient temperature 3: 52 percent / silica gel / toluene / Heating View Scheme

sodium hydrogencarbonate in toluene T=40 - 50°C; 1.5 h;

1: 92 percent / aq. NaHCO3 / toluene / 1.5 h / 40 - 50 °C 2: 25 g / NH3 / ethyl acetate / 3 h / Ambient temperature 3: 52 percent / silica gel / toluene / Heating 4: P2S5, NaHCO3 / bis-(2-methoxy-ethyl) ether / 3 h / 70 - 80 °C 5: 6 g / hydrazine / tetrahydrofuran / 0.5 h / 45 - 80 °C 6: 80 percent / 1 h / 80 °C View Scheme

1: 92 percent / aq. NaHCO3 / toluene / 1.5 h / 40 - 50 °C 2: 25 g / NH3 / ethyl acetate / 3 h / Ambient temperature 3: 52 percent / silica gel / toluene / Heating 4: P2S5, NaHCO3 / bis-(2-methoxy-ethyl) ether / 3 h / 70 - 80 °C 5: 6 g / hydrazine / tetrahydrofuran / 0.5 h / 45 - 80 °C 6: 80 percent / 1 h / 80 °C 7: 98 percent / KOH / methanol View Scheme