1: 3-methylamino-4,4,4-trifluorobut-2-enoic acid ethyl ester in DMF (N,N-dimethyl-formamide); pentane 0.75 h; Heating / reflux; 2: With potassium tert-butylate in DMF (N,N-dimethyl-formamide) T=40 - 45°C; 0.583333 h; 3: N-(2-chloro-4-fluoro-5-isocyanatobenzoyl)-N'-methyl-(1-methylethyl)sulfamide in DMF (N,N-dimethyl-formamide) T=-15 - 22°C; 1.03333 h; Product distribution / selectivity;