iron; ammonium chloride in ethanol T=25 - 90°C; 2 h;

1: 54 percent / toluene / 2 h / 100 °C 3: 67 percent / phosphorus pentasulphide / pyridine / 4.5 h / Heating 4: 71 percent / chlorine, conc. hydrochloric acid / 0.33 h View Scheme

1: 54 percent / toluene / 2 h / 100 °C 2: 1.) nitrosyl chloride, anhydrous potassium acetate, 2.) anhydrous sodium carbonate / 1.) acetic anhydride, acetic acid, 30 min, 2.) benzene, 2 h, reflux View Scheme

1: 54 percent / toluene / 2 h / 100 °C 2: 1.) phosphorus pentaoxide, potassium acetate, nitrosyl chloride, 2.) sodium carbonate / 1.) acetic acid, 30 min, 2.) benzene, 2 h, reflux View Scheme

1: 54 percent / toluene / 2 h / 100 °C 2: 1.) phosphorus pentaoxide, potassium acetate, nitrosyl chloride, 2.) sodium carbonate / 1.) acetic acid, 30 min, 2.) benzene, 2 h, reflux 3: 31 percent / 3 h / Heating View Scheme