Ethyl bromoacetate → 6-Nitro-2H-1,4-benzoxazin-3(4H)-one

To a mixture of 10.6 g (182 mmol) of potassium fluoride and 55 ml of anhydrous dimethylformamide was added 7.76 ml (72 mmol) of ethyl bromoacetate and the reaction mixture was stirred at room temperature for 15 minutes. Then 10.79 g (70.0 mmol) of 2-amino-4-nitrophenol was added and the reaction mixture was heated to 55° C. for 6 hours. The reaction mixture was cooled slowly to room temperature, stirred for 12 hours and poured onto 300 ml ice. The solid which formed was filtered off, washed with water and dried (20-50 Torr, 50° C., 16 hrs). The resulting orange solid was taken up in 100 ml EtOAc and 100 ml H2O. The aqueous layer was extracted with EtOAc (2×100 ml). The organic layers were then combined and washed with water (3×150 ml) and 10% HCl and dried (MgSO4). The solvent was removed in vacuo and the resulting solid was recrystallized from ethylene dichloride to yield 3.6 g (27% yield) of 6-nitro-2H-1,4-benzoxazin-3(4H)-one as an orange solid, m.p. 221°-223° C.

1. temperaturethe reaction mixture was heated to 55° C. for 6 hours
2. temperatureThe reaction mixture was cooled slowly to room temperature
3. stirringstirred for 12 hours
4. customThe solid which formed
5. filtrationwas filtered off
6. washwashed with water
7. customdried (20-50 Torr, 50° C., 16 hrs)
8. extractionThe aqueous layer was extracted with EtOAc (2×100 ml)
9. washwashed with water (3×150 ml) and 10% HCl
10. dry with materialdried (MgSO4)
11. customThe solvent was removed in vacuo
12. customthe resulting solid was recrystallized from ethylene dichloride

ORD record

ord-fb583f94978d469d828b2fe42af1d687

Source dataset

uspto-grants-1993_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05238908