Reaktion #3492

Reaktionsgleichung

Benzylbromide

NaH

ethyl acetoacetate

→

ethyl-benzylacetoacetate

Lösungsmittel

THF

THF

hexane

Reaktionsbedingungen

Aufarbeitung

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

Vorschrift

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).

Quelle