Réaction #4075

Équation de réaction

ethyl acetoacetate

mesityl oxide

heptane

→

ester

Rendement 27.0%

Ethyl 4-Oxo-2,6,6-Trimethylcyclohex-2-Ene-1-Carboxylate

Rendement 27.0%

Solvants

toluene

Conditions de réaction

Traitement

1. 1
   Températurewas heated
2. 2
   Températureat reflux in a 5000 ml round bottom flask
3. 3
   AutreThe flask was equipped with a Dean-Stark trap
4. 4
   Autredrying tube
5. 5
   workup.ADDITIONan additional 25 g of zinc chloride was added
6. 6
   Températurerefluxing
7. 7
   workup.WAITcontinued for 36 h
8. 8
   TempératureAfter cooling
9. 9
   Lavagethe reaction mixture was washed with 1500 ml of water, 5% sodium bicarbonate solution (2×1000 ml)
10. 10
    AutreRemoval of solvent
11. 11
    Autreby evaporation
12. 12
    Autreyielded 979 g of crude product
13. 13
    workup.DISTILLATIONDistillation of the crude product

Mode opératoire

A mixture of 1020 ml (1041 g, 8.00 mol) of ethyl acetoacetate, 960 ml (824 g, 8.40 mol) of mesityl oxide, 1000 ml of heptane, 600 ml of toluene, and 175 g of zinc chloride was heated at reflux in a 5000 ml round bottom flask while stirring. The flask was equipped with a Dean-Stark trap and drying tube. After 24 h, an additional 25 g of zinc chloride was added and refluxing continued for 36 h. After cooling, the reaction mixture was washed with 1500 ml of water, 5% sodium bicarbonate solution (2×1000 ml), and another 1500 ml of water. Removal of solvent by evaporation yielded 979 g of crude product. Distillation of the crude product provided 453.5 g of the desired ester which represents 27.0% yield. Distillation was at 124°-5° C. (3.0 torr).

Source