Реакция #65394

Уравнение реакции

6-cyano-3,4-dihydro-2,2-dimethyl-2H-1,4-benzoxazine

cyclohexane-1,2-dione

p-toluenesulfonic acid

→

6-cyano-3,4-dihydro-2,2-dimethyl-4-(6-oxo-1-cyclohexen-1-yl)-2H-1,4-benzoxazine

Выход 66.7%

Растворители

toluene

Условия реакции

Обработка

1. 1
   Температураthe solution was refluxed
2. 2
   Температураunder heating for 4 hours
3. 3
   ТемператураAfter cooling
4. 4
   Промывкаthe reaction mixture was washed with saturated aqueous sodium hydrogen carbonate solution and aqueous sodium chloride solution
5. 5
   Сушкаdried over anhydrous magnesium sulfate
6. 6
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
7. 7
   ДругоеThe residue was purified by silica gel column chromatography
8. 8
   Промывкаthe resulting crude crystals were washed with ethanol

Методика

In 15 ml of toluene were dissolved 0.5 g of 6-cyano-3,4-dihydro-2,2-dimethyl-2H-1,4-benzoxazine, 0.33 g of cyclohexane-1,2-dione and a catalytic amount of p-toluenesulfonic acid and using a Dean-Stark trap, the solution was refluxed under heating for 4 hours. After cooling, the reaction mixture was washed with saturated aqueous sodium hydrogen carbonate solution and aqueous sodium chloride solution and dried over anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography and the resulting crude crystals were washed with ethanol to give 0.5 g of 6-cyano-3,4-dihydro-2,2-dimethyl-4-(6-oxo-1-cyclohexen-1-yl)-2H-1,4-benzoxazine.

Источник