Reacción #2308

Ecuación de reacción

methyl bromoacetate

3,5-dichloro-4-hydroxyacetophenone

Sodium hydride

hexane

→

methyl 4-acetyl-2,6-dichlorophenoxyacetate

Disolventes

water

DMF

DMF

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturacooling (ice-bath)
2. 2
   workup.STIRRINGStirring
3. 3
   workup.STIRRINGstirring
4. 4
   workup.WAITwas continued for a further 18 hours at ambient temperature
5. 5
   Extracciónthe mixture was extracted twice with ethyl acetate
6. 6
   Secadothe organic phases dried (MgSO4)
7. 7
   Filtraciónfiltered
8. 8
   Otroevaporated
9. 9
   OtroThe residue, after recrystallisation from hexane (250 ml)

Procedimiento

Sodium hydride (50% w/w dispersion in mineral oil, 1.32 g) was treated under argon with repeated washes of hexane. The oil-free residue was suspended in dry DMF (10 ml) and, with stirring and cooling (ice-bath), a solution of 3,5-dichloro-4-hydroxyacetophenone (5.13 g) in dry DMF (15 ml) was added dropwise. Stirring was continued for 30 minutes when methyl bromoacetate (3.06 ml) was added dropwise and stirring was continued for a further 18 hours at ambient temperature. The reaction mixture was added to water, the mixture was extracted twice with ethyl acetate, the organic phases dried (MgSO4), filtered and then evaporated. The residue, after recrystallisation from hexane (250 ml), gave methyl 4-acetyl-2,6-dichlorophenoxyacetate, 4.25 g, as white crystals: NMR (d6DMSO) δ 8.00 (2H, s), 4.80 (2H, s), 3.73 (3H, s), 2.59 (3H, s).

Fuente