تفاعل #2308

معادلة التفاعل

methyl bromoacetate

3,5-dichloro-4-hydroxyacetophenone

Sodium hydride

hexane

→

methyl 4-acetyl-2,6-dichlorophenoxyacetate

المذيبات

water

DMF

DMF

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةcooling (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
   استخلاصthe mixture was extracted twice with ethyl acetate
6. 6
   تجفيفthe organic phases dried (MgSO4)
7. 7
   ترشيحfiltered
8. 8
   أخرىevaporated
9. 9
   أخرىThe residue, after recrystallisation from hexane (250 ml)

الإجراء التجريبي

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).

المصدر