1: 74 percent / hydroxyl amine-O-sulphonic acid / aq. NaOH / 24 h / Ambient temperature 2: 39 percent / 1 h / 180 °C 3: (NH4)2SO4 / 6 h / Heating 4: 1.) SnCl4 2.) 25percent aq. NH3 / 1.) CH3CN, 1 h, reflux, 2.) MeOH, 12 h View Scheme

1: (NH4)2SO4 / 6 h / Heating 2: 1.) SnCl4 2.) 25percent aq. NH3 / 1.) CH3CN, 1 h, reflux, 2.) MeOH, 12 h View Scheme

ammonium hydroxide; tin(IV) chloride 1.) CH3CN, 1 h, reflux, 2.) MeOH, 12 h; Yield given. Multistep reaction;