sodium hydroxide in water; dimethyl sulfoxide T=120°C; 8 h;

sodium hydroxide in water; dimethyl sulfoxide T=120°C; 3 h;

1: triethylamine / CHCl3 / 1.) 3h, reflux, 2.) room temp. 2: HCl / dioxane; H2O / 1 h / 100 °C 3: sulphur / 3 h / Heating 4: 90 percent / NaOH / H2O; dimethylsulfoxide / 8 h / 120 °C View Scheme

1: 1.) diisobutylaluminum hydride 2.) sulphuric acid / 1.) toluene, -5 deg C, 1 h; 2.) ethanol, water 2: triethylamine / CHCl3 / 1.) 3h, reflux, 2.) room temp. 3: HCl / dioxane; H2O / 1 h / 100 °C 4: sulphur / 3 h / Heating 5: 90 percent / NaOH / H2O; dimethylsulfoxide / 8 h / 120 °C View Scheme

1: 91 percent / dibenzo-18-crown-6 / acetonitrile / 1.) 50 deg C, 2.) 3 h, 80 deg C 2: 82.1 percent / NaOH / dimethylsulfoxide; H2O / 3 h / 120 °C View Scheme

1: 89 percent / 63percent HBr / H2O / 8 h / 80 - 90 °C 2: 91 percent / dibenzo-18-crown-6 / acetonitrile / 1.) 50 deg C, 2.) 3 h, 80 deg C 3: 82.1 percent / NaOH / dimethylsulfoxide; H2O / 3 h / 120 °C View Scheme

1: sulphur / 3 h / Heating 2: 90 percent / NaOH / H2O; dimethylsulfoxide / 8 h / 120 °C View Scheme

1: 98.5 percent / diisobutylaluminum hydride / toluene / 1.) 15 min. -10 deg C. 2.) 2 h, room temp. 2: 89 percent / 63percent HBr / H2O / 8 h / 80 - 90 °C 3: 91 percent / dibenzo-18-crown-6 / acetonitrile / 1.) 50 deg C, 2.) 3 h, 80 deg C 4: 82.1 percent / NaOH / dimethylsulfoxide; H2O / 3 h / 120 °C View Scheme

1: HCl / dioxane; H2O / 1 h / 100 °C 2: sulphur / 3 h / Heating 3: 90 percent / NaOH / H2O; dimethylsulfoxide / 8 h / 120 °C View Scheme

1: 90 percent / HCl / dioxane; H2O / 1 h / 100 °C 2: 98.5 percent / diisobutylaluminum hydride / toluene / 1.) 15 min. -10 deg C. 2.) 2 h, room temp. 3: 89 percent / 63percent HBr / H2O / 8 h / 80 - 90 °C 4: 91 percent / dibenzo-18-crown-6 / acetonitrile / 1.) 50 deg C, 2.) 3 h, 80 deg C 5: 82.1 percent / NaOH / dimethylsulfoxide; H2O / 3 h / 120 °C View Scheme