1: With hydrogenchloride; acetic acid; sodium nitrite in water; acetonitrile T=0 - 5°C; 0.5 h; 2: With sulfur dioxide in water; acetonitrile T=7°C; 0.5 h; 3: With copper dichloride in water; acetonitrile T=20°C; 16 h;

n-butyllithium 1.) THF, hexane, -70 deg C, 45 min, 2.) THF, hexane, -70 deg C, 2 h; Yield given. Multistep reaction;

water Heating;

1: Na2SO3*7H2O, aq. NaHCO3 2: aq. NaHCO3 / methanol / Heating View Scheme