Réaction #1552088

Équation de réaction

hydrochloric acid

sodium

3-(difluoromethyl)-5-fluoro-1-methyl-1H-pyrazole-4-carbonyl fluoride

tetra-hydrothiophene-1,1-dioxide

→

3-(difluoromethyl)-5-fluoro-1-methyl-1H-pyrazole-4-carboxylic acid

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONThe temperature is kept below 20° C. during the addition
2. 2
   FiltrationThe resulting white precipitate is filtered
3. 3
   Lavagewashed with water
4. 4
   Autredried

Mode opératoire

To 400 ml of a 1N sodium hydroxyde aqueous solution, is added dropwise 67.5 g of a solution (10% molar) of 3-(difluoromethyl)-5-fluoro-1-methyl-1H-pyrazole-4-carbonyl fluoride in tetra-hydrothiophene-1,1-dioxide. The temperature is kept below 20° C. during the addition. After 2 hours of stirring at room temperature, the reaction mixture is carefully acidified to pH 2 with concentrated aqueous hydrochloric acid. The resulting white precipitate is filtered, washed with water, and dried to yield 6 g of 3-(difluoromethyl)-5-fluoro-1-methyl-1H-pyrazole-4-carboxylic acid as a white solid. 1H NMR (400 MHz, DMSO-d6) δ ppm: 3.90 (s, 3H); 7.22 (t, 1H, JHF=53.55 Hz); 13.33 (s, 1H).

Source