hydrogenchloride; Dowex 50(H+) T=100 - 110°C; 24 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

Multi-step reaction with 2 steps 1: 95 percent / electrolyte Bu4NBF4 / 1.13 h / 10 °C / Pt-anode2: SnCl4 / H2O / 48 h / Ambient temperature  

Multi-step reaction with 5 steps 1: 90 percent / 1 N HCl / various solvent(s)2: 69 percent / KOH3: 80 percent / 3 h / Heating4: 95 percent / electrolyte Bu4NBF4 / 1.13 h / 10 °C / Pt-anode5: SnCl4 / H2O / 48 h / Ambient temperature