1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: p.toluenesulfonic acid / benzene / Heating 4: Na / various solvent(s) / Heating 5: 70 percent / NaOH / ethanol / Heating 6: 55 percent / neat (no solvent) / Heating 7: 71 percent / sulfur / neat (no solvent) / 0.5 h / 260 °C View Scheme

1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: p.toluenesulfonic acid / benzene / Heating 4: Na / various solvent(s) / Heating 5: 98 percent / NaOH / ethanol / Heating 6: 85 percent / neat (no solvent) / Heating 7: 90 percent / H2 / Pd/C / methanol / 6 h / Ambient temperature 8: 79 percent / Na / ethanol / 11 h / Heating View Scheme

1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: 15.5 g / p.toluenesulfonic acid / benzene / 6 h / Heating 4: Na / various solvent(s) / 1 h / Heating 5: 83 percent / NaOH / ethanol / 2.5 h / Heating 6: sulfur / neat (no solvent) / 1 h / 260 °C View Scheme

1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: 15.5 g / p.toluenesulfonic acid / benzene / 6 h / Heating 4: Na / various solvent(s) / 1 h / Heating 5: 83 percent / NaOH / ethanol / 2.5 h / Heating 6: 80 percent / neat (no solvent) / 0.33 h / 250 °C View Scheme

1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: p.toluenesulfonic acid / benzene / Heating 4: Na / various solvent(s) / Heating 5: 70 percent / NaOH / ethanol / Heating 6: 55 percent / neat (no solvent) / Heating View Scheme

1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: p.toluenesulfonic acid / benzene / Heating 4: Na / various solvent(s) / Heating 5: 98 percent / NaOH / ethanol / Heating 6: 85 percent / neat (no solvent) / Heating View Scheme

1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: p.toluenesulfonic acid / benzene / Heating 4: Na / various solvent(s) / Heating 5: 98 percent / NaOH / ethanol / Heating 6: 85 percent / neat (no solvent) / Heating 7: 90 percent / H2 / Pd/C / methanol / 6 h / Ambient temperature View Scheme

1: 1.) NaNO2, HCl 2: 1.) SnCl2, conc. HCl; 2.) 2.5percent HCl / 1.) 15 h; 2.) reflux, 5 min 3: p.toluenesulfonic acid / benzene / Heating 4: Na / various solvent(s) / Heating 5: 98 percent / NaOH / ethanol / Heating 6: 85 percent / neat (no solvent) / Heating 7: 90 percent / H2 / Pd/C / methanol / 6 h / Ambient temperature 8: 69 percent / K2CO3 / dimethylformamide / 6 h / 80 °C View Scheme