Reaktion #348153

Reaktionsgleichung

2-chloro-5-(4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl)-4-fluorobenzoic acid

oxalyl chloride

methylene chloride

→

2-chloro-5-[4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-4-fluorobenzoic acid, 1-methylethyl ester

Ausbeute 70.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   EinengenThe solution was concentrated in vacuo
2. 2
   workup.DISSOLUTIONthe resultant residue dissolved in 25 mL isopropanol
3. 3
   TemperaturThe solution was cooled
4. 4
   workup.ADDITIONpoured into 200 mL cold water
5. 5
   Filtrationthe solid filtered
6. 6
   Sonstigedried
7. 7
   SonstigeThe product was recrystallized from ethanol/water

Vorschrift

To a solution of 4.3 g (0.012 mole) 2-chloro-5-(4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl)-4-fluorobenzoic acid in 50 mL methylene chloride was added 3.1 mL (0.036 mole) oxalyl chloride causing the evolution of gas. When this evolution ceased, one drop of DMF was added and the solution stirred until the gas evolution ceased. The solution was concentrated in vacuo and the resultant residue dissolved in 25 mL isopropanol and heated to 60° C. for 1 hour. The solution was cooled, poured into 200 mL cold water and the solid filtered and dried. The product was recrystallized from ethanol/water to yield 1.69 g (70%) of 2-chloro-5-[4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-4-fluorobenzoic acid, 1-methylethyl ester as a white solid; mp 69° C.

Quelle