Reacción #2186223

Ecuación de reacción

sodium hydroxide

5-amino-1 -(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinyl-1 H-pyrazole-3-carbonitrile

sulfuric acid

→

title compound

Rendimiento 77.0%

5-Amino-1-(2,6-dichloro-4-trifluoromethylphenyl)-1H-pyrazole-3-carboxylic acid

Rendimiento 77.0%

Condiciones de reacción

Tratamiento posterior

1. 1
   Extracciónextracted with ethyl acetate
2. 2
   SecadoThe organic phase was dried over magnesium sulfate
3. 3
   Otroevaporated to dryness
4. 4
   Otropurified by flash chomatography (silica, chloroform/ethanol) with subsequently trituration with tetrachloromethane

Procedimiento

A stirred mixture of 5-amino-1 -(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinyl-1 H-pyrazole-3-carbonitrile (5.00 g, 11.4 mmol) and sulfuric acid (50%, 100 ml) was heated to 135° C. for 3 hours. The cooled mixture was added to ice water and the pH adjusted to 4 by the addition of aqueous sodium hydroxide (6 N, approx. 230 ml), and then extracted with ethyl acetate. The organic phase was dried over magnesium sulfate, evaporated to dryness and purified by flash chomatography (silica, chloroform/ethanol) with subsequently trituration with tetrachloromethane to give the title compound (3.00 g, yield 77%) as off-white crystals, mp 213° C., 1H NMR (DMSO-d6): 5.69 (bs, 2H, NH2), 5.76 (s, 1H, pyrazole-H), and 8.20 (s, 2H, Ar—H).

Fuente