Реакция #55558

Уравнение реакции

Jones reagent

1-(m-trifluoromethylphenyl)pyrazole-4-carboxaldehyde

Jones reagent

sulfuric acid

Jones reagent

acetone

→

1-(m-trifluoromethylphenyl)pyrazole-4-carboxylic acid

Выход 89.0%

Растворители

water

Условия реакции

Обработка

1. 1
   ДругоеErlenmeyer flask, fitted with a thermometer and a magnetic stirrer
2. 2
   workup.ADDITIONcontaining a solution of 8.3 g
3. 3
   workup.DISSOLUTIONby dissolving 26.7 g
4. 4
   Температураis cooled by an ice water bath
5. 5
   Температураunder cooling, for 15 minutes
6. 6
   Другоеafter which time it is quenched with a large volume of water
7. 7
   workup.WAITto stand at room temperature for about 3 hours
8. 8
   ДругоеThe resultant precipitated solids
9. 9
   Фильтрацияare then filtered
10. 10
    Промывкаwashed successively with water and petroleum ether
11. 11
    ДругоеThe solvent is then removed under vacuum

Методика

Into a 500 ml. Erlenmeyer flask, fitted with a thermometer and a magnetic stirrer, containing a solution of 8.3 g. (0.0346 M.) of 1-(m-trifluoromethylphenyl)pyrazole-4-carboxaldehyde in 300 ml. of acetone is slowly added 20.0 ml. of Jones reagent (prepared by dissolving 26.7 g. of chromium trioxide in 23.0 ml. of concentrated sulfuric acid and then diluting to 100 ml. with water), the addition of the Jones reagent being effected while the solution is cooled by an ice water bath. Upon completion of the addition of the Jones reagent, the reaction mixture is stirred, under cooling, for 15 minutes and then for an additional 20 minutes at room temperature, after which time it is quenched with a large volume of water and allowed to stand at room temperature for about 3 hours. The resultant precipitated solids are then filtered and washed successively with water and petroleum ether. The solvent is then removed under vacuum to yield 1-(m-trifluoromethylphenyl)pyrazole-4-carboxylic acid, m.p. 145°-148° C. (Yield: 89%).

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