Reaktion #65400

Reaktionsgleichung

potassium carbonate

3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H-1,4-benzoxazine

ethyl bromoacetate

potassium carbonate

acetonitrile

ethyl bromoacetate

→

ethyl (3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H1,4 -benzoxazin-4-yl)acetate

Ausbeute 80.1%

Lösungsmittel

N,N-dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas refluxed
2. 2
   Temperaturunder heating for 2.5 hours
3. 3
   workup.STIRRINGAfter an hour of stirring at 80° C.
4. 4
   workup.STIRRINGthe mixture was further stirred at 80° C. for 1 hour
5. 5
   EinengenThe reaction mixture was then concentrated under reduced pressure
6. 6
   Sonstigethe residue was chromatographed on a silica gel column, elution
7. 7
   SonstigeThe crystals from the eluate were recrystallized from ethyl acetate-hexane

Vorschrift

A mixture of 6.66 g of 3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H-1,4-benzoxazine, 5.51 g of ethyl bromoacetate, 4.5.6 g of potassium carbonate and 20 ml of acetonitrile was refluxed under heating for 2.5 hours. Then, 10 ml of N,N-dimethylformamide was added and the mixture was stirred at 80° C. for 2 hours. To this mixture was added 2-80 g of ethyl bromoacetate. After an hour of stirring at 80° C., 2.28 g of potassium carbonate was added and the mixture was further stirred at 80° C. for 1 hour. The reaction mixture was then concentrated under reduced pressure and the residue was chromatographed on a silica gel column, elution being carried out with hexane-ethyl acetate (10:.1). The crystals from the eluate were recrystallized from ethyl acetate-hexane to give 7.4 g of ethyl (3,4-dihydro-2,2-dimethyl-6-nitro-3-oxo-2H1,4 -benzoxazin-4-yl)acetate. This compound has the following physicochemical properties.

Quelle