Reacción #76182

Ecuación de reacción

acetyl chloride

sulfuric acid

2,4-dichloro-5-fluoro-3-methoxybromobenzene

magnesium

tetrahydrofuran

→

2,4-dichloro-5-fluoro-3-methoxyacetylbenzene

Rendimiento 81.6%

Disolventes

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrothe reaction
2. 2
   TemperaturaThe temperature of the reaction was then increased to room temperature
3. 3
   workup.STIRRINGThe resulting mixture was stirred for 5 minutes
4. 4
   OtroThe organic phase was separated off
5. 5
   ExtracciónThe aqueous layer was extracted by toluene
6. 6
   LavadoThe combined organic phases were washed successively with aqueous solution of sodium chloride, aqueous solution of sodium bicarbonate and water
7. 7
   Secadodried over anhydrous sodium sulfate
8. 8
   OtroThe solvent was evaporated under reduced pressure
9. 9
   OtroThe residue was recrystallized from ethanol

Procedimiento

0.20 mol of 2,4-dichloro-5-fluoro-3-methoxybromobenzene, 0.22 mol of powder of magnesium, 0.24 mol of cuprous chloride in 240 ml of tetrahydrofuran were stirred at ambient temperature to initiate the reaction, and then quickly cooled to −30±10° C. The reaction was monitored by TLC to be finished. A solution of acetyl chloride (0.30 mol) in 50 ml of toluene was added dropwise to the resulting mixture. The reaction was carried out at −30±110° C. for 8 hours. The temperature of the reaction was then increased to room temperature and stirred for 3 hours. The reactant was poured into a mixture of 170 g of crushed ice containing 75 ml of 25% aqueous solution of sulfuric acid. The resulting mixture was stirred for 5 minutes. The organic phase was separated off. The aqueous layer was extracted by toluene. The combined organic phases were washed successively with aqueous solution of sodium chloride, aqueous solution of sodium bicarbonate and water, and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure. The residue was recrystallized from ethanol to afford 38.7 g of 2,4-dichloro-5-fluoro-3-methoxyacetylbenzene (0.163 mol) in 81.6% yield, mp. 36.7-39.4° C.

Fuente