Реакция #3492

Уравнение реакции

Benzylbromide

NaH

ethyl acetoacetate

→

ethyl-benzylacetoacetate

Растворители

THF

THF

hexane

Условия реакции

Обработка

1. 1
   workup.ADDITIONAfter the addition
2. 2
   workup.STIRRINGThe reaction mixture was stirred overnight at room temperature
3. 3
   ДругоеThe reaction was terminated the next day
4. 4
   workup.ADDITIONby pouring into ice cold water
5. 5
   Экстракцияextracted with ether/ethylacetate
6. 6
   ПромывкаThe combined ether/ethylacetate extracts were rinsed over brine
7. 7
   Сушкаdried over Na2SO4
8. 8
   ДругоеRemoval of the solvent
9. 9
   workup.DISTILLATIONfollowed by careful vacuum distillation

Методика

NaH (13.8 g, 0.6 mole) was washed twice with hexane (2×50 ml) and suspended in 250 ml of freshly distilled THF. Next ethyl acetoacetate (75 ml, excess) was added dropwise carefully while the receiving flask was cooled at -10° C. After the addition was complete, it was stirred at -10° C. for 2 hours and at room temperature for 30 min. Benzylbromide (51.0 g, 0.3 mole) in THF was added dropwise at room temperature to the above solution. The reaction mixture was stirred overnight at room temperature. The reaction was terminated the next day by pouring into ice cold water, brought to neutral pH, and extracted with ether/ethylacetate. The combined ether/ethylacetate extracts were rinsed over brine and dried over Na2SO4. Removal of the solvent followed by careful vacuum distillation gave ethyl-benzylacetoacetate, bp 276° C. IR: (neat), cm-1 : 2900-3050, 1690-1760 (broad), 1655. NMR (CDCl3):δ:1.25 (t1 3H, CH2CH3); 2.25 (s, 3H, COCH3); 3.20 (d, 2H, benzylic CH2); 3.8 (t, 1H, COCHCO); 4.20 (q, 2H, OCH2CH3); 7.15-7.35 (m, 5H, Ar-H).

Источник