acetic anhydride; toluene-4-sulfonic acid 5 h; Heating;

1: 95 percent / hydroxylamine hydrochloride, K2CO3 / aq. ethanol / 2 h / Ambient temperature 2: 65 percent / p-toluenesulfonic acid, acetic anhydride / 5 h / Heating View Scheme

2: 95 percent / hydroxylamine hydrochloride, K2CO3 / aq. ethanol / 2 h / Ambient temperature 3: 65 percent / p-toluenesulfonic acid, acetic anhydride / 5 h / Heating View Scheme