反応 #2186223

反応方程式

sodium hydroxide

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

sulfuric acid

→

title compound

収率 77.0%

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

収率 77.0%

反応条件

後処理

1. 1
   抽出extracted with ethyl acetate
2. 2
   乾燥The organic phase was dried over magnesium sulfate
3. 3
   その他evaporated to dryness
4. 4
   その他purified by flash chomatography (silica, chloroform/ethanol) with subsequently trituration with tetrachloromethane

実験手順

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).

出典