2,6-Lutidine → 5-amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-1H-pyrazole-3-carbonitrile

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Reaction Steps

A 50 mL round-bottom flask was charged with (2,6-dichloro-4-trifluoromethyl-phenyl)-hydrazine (1.2 g, 4.84 mmol), 2,6-lutidine (0.57 g, 5.32 mmol, 1.1 equiv.) and methanol (10 mL). A mixture of chloromaleonitrile and chlorofumaronitrile (0.82 g, 7.29 mmol) was slowly added at 20-25° C. Stirring was continued for about 16 hours at that temperature. The solution was then concentrated at a pressure of 50 mbar. The residue was purified by flash column chromatography (silica, hexanes/EtOAc 100:0→70:30) to give the product as a off-white solid (1.1 g, 3.43 mmol, 71%), melting point: 117-118° C., 1H-NMR (360 MHz, CDCl3): δ [ppm]=7.78 (d, 2H, J=0.4 Hz); 6.04 (s, 1H); 3.83 (bs, 2H), 13C-NMR (125 MHz, DMSO-d6): δ [ppm]=150.0; 136.0; 135.9; 132.7 (q, J=34 Hz); 126.43; 126.42; 122.4 (q, J=273 Hz); 114.6; 90.8.

Provenance & Evidence