sulfuric acid T=90°C; 2.5 h; Inert atmosphere;

pyridinium chlorochromate in 1,2-dichloro-ethane T=80°C; 3 h;

1: aqueous hydrochloric acid; sodium sulfate; hydroxylamine 2: sulfuric acid View Scheme

1: With hydroxylamine hydrochloride; sodium sulfate Heating; 2: With sulfuric acid T=60 - 80°C;

1: With dihydrogen peroxide; sodium hydroxide in water T=20°C; Cooling with ice; 2: With citric acid in water

1: sodium hydroxide; dihydrogen peroxide / water / 0 - 20 °C / |Inert atmosphere 2: hydrogenchloride / water / 12 h / |Reflux; |Inert atmosphere 3: palladium 10 on activated carbon; hydrogen / methanol / 8 h / |Inert atmosphere 4: water / 0.75 h / |Reflux; |Inert atmosphere View Scheme

1: sodium hydroxide; dihydrogen peroxide / water / 0 - 20 °C / |Inert atmosphere 2: hydrogenchloride / water / 12 h / |Reflux; |Inert atmosphere View Scheme

1: sodium hydroxide; dihydrogen peroxide / water / 0 - 20 °C / |Inert atmosphere 2: hydrogenchloride / water / 12 h / |Reflux; |Inert atmosphere 3: palladium 10 on activated carbon; hydrogen / methanol / 8 h / |Inert atmosphere View Scheme