dihydrogen peroxide in acetic anhydride; acetic acid

1: With hydrogenchloride; sodium nitrite in water; acetic acid T=-10°C; 2: With sulfur dioxide; copper dichloride in water; acetic acid T=20°C;

1.1: 75 percent / KOH / ethanol / 3 h / Heating 2.1: hydrochloric acid; NaNO2 / acetic acid; H2O / -10 °C 2.2: SO2; CuCl2 / acetic acid; H2O / 20 °C View Scheme

1.1: 40 percent / NaHCO3 / H2O / 20 h / Heating 2.1: 75 percent / KOH / ethanol / 3 h / Heating 3.1: hydrochloric acid; NaNO2 / acetic acid; H2O / -10 °C 3.2: SO2; CuCl2 / acetic acid; H2O / 20 °C View Scheme

1.1: 100 percent / Na2SO3; NaHCO3 / H2O / 3 h / 90 °C 2.1: 40 percent / NaHCO3 / H2O / 20 h / Heating 3.1: 75 percent / KOH / ethanol / 3 h / Heating 4.1: hydrochloric acid; NaNO2 / acetic acid; H2O / -10 °C 4.2: SO2; CuCl2 / acetic acid; H2O / 20 °C View Scheme

pyridine in dichloromethane T=20°C; 6 h;