تفاعل #3492

معادلة التفاعل

Benzylbromide

NaH

ethyl acetoacetate

→

ethyl-benzylacetoacetate

المذيبات

THF

THF

hexane

ظروف التفاعل

المعالجة

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

الإجراء التجريبي

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).

المصدر