sulfuric acid; boric acid; sodium nitrite T=200°C;

sulfuric acid; nitric acid; boric acid T=0°C; 2 h; Yields of byproduct given;

sulfuric acid T=50°C; 1 h; Yield given. Yields of byproduct given;

in xylene 12 h; Ambient temperature;

in xylene 24 h; Ambient temperature;

hydrogenchloride 1.) xylene, room temperature, 24 h, 2.) reflux, 7 h; Yield given. Multistep reaction;

1: 50 percent / ZnCl2, SOCl2 / 15 h / Heating 2: 44 percent / potassium carbonate / dimethylsulfoxide / 1 h / 20 °C 3: 70 percent / conc. H2SO4, boric acid / 0.5 h / 80 °C 4: 72 percent / conc. H2SO4, boric acid / 0.5 h / 80 °C 5: 91 percent / K2CO3 / acetone / 4 h / Heating 6: 74 percent / KOH, sulfamic acid / 9 h / Heating 7: 93 percent / conc. H2SO4, boric acid / 2 h / 130 - 140 °C View Scheme

1: 50 percent / ZnCl2, SOCl2 / 15 h / Heating 2: 44 percent / potassium carbonate / dimethylsulfoxide / 1 h / 20 °C 3: 70 percent / conc. H2SO4, boric acid / 0.5 h / 80 °C 4: 72 percent / conc. H2SO4, boric acid / 0.5 h / 80 °C 5: 91 percent / K2CO3 / acetone / 4 h / Heating 6: 74 percent / KOH, sulfamic acid / 9 h / Heating 7: 83 percent / boron trifluoride etherate / toluene / 4 h / Heating View Scheme