Diisopropylethylamine → HCID 59623743, compound

To a solution of 3-(2-chloro-5-trifluoromethyl-phenylmethanesulfonylamino)-pyrazine-2-carboxylic acid methyl ester (Example 2.1) (1.5 g) in acetonitrile (15 ml) was added N,N-diisopropylethylamine (“Hunig's base”) (0.71 ml) at ambient temperature. The mixture was stirred for 5 minutes at ambient temperature before dropwise addition of a solution of 2,2-difluoroethyltrifluoromethanesulfonate (1.2 g) in acetonitrile (5 ml) at ambient temperature. The reaction mixture was stirred at ambient temperature for 44 hours. The reaction mixture was concentrated. The residue was purified by column chromatography on silica gel (eluent: dichloromethane) to give 3-[(2-chloro-5-trifluoromethyl-phenylmethanesulfonyl)-(2,2-difluoro-ethyl)-amino]-pyrazine-2-carboxylic acid methyl ester as a light yellow solid (1.300 g). 1H-NMR (400 MHz, CDCl3): 8.63 (s, 1H), 8.53 (s, 1H), 7.76 (m, 1H), 7.53-7.59 (m, 2H), 6.15 (tt, 1H), 4.69 (s, 2H), 4.23-4.31 (m, 2H), 4.02 (s, 3H) ppm.