1: sulfuryl dichloride / dichloromethane / 18 h / 20 °C / |Inert atmosphere 2: lithium hydroxide hydrate / ethanol; water / 1 h / |Reflux 3: oxalyl dichloride; N,N-dimethyl-formamide / dichloromethane 4: N,N-dimethyl-formamide; triethylamine / dichloromethane / 0.25 h 5: trifluoroacetic acid / dichloromethane / 1 h / 20 °C View Scheme

1: sulfuryl dichloride / dichloromethane / 18 h / 20 °C / |Inert atmosphere 2: lithium hydroxide hydrate / ethanol; water / 1 h / |Reflux View Scheme

sulfuryl dichloride in dichloromethane T=20°C; 18 h; Inert atmosphere;