oxalyl dichloride; water; N,N-dimethyl-formamide in dichloromethane T=10 - 23°C; 2.16667 h; Product distribution / selectivity;

1: With chlorosulfonic acid in dichloromethane T=-5 - 22°C; 1 - 2 h; 2: With oxalyl dichloride; N,N-dimethyl-formamide in dichloromethane T=20°C; 19 - 20 h; Heating / reflux; Product distribution / selectivity;