Dichloromethane → 2,2-difluoro-4-methyl-7-amino-4H-1,4-benzoxazin-3-one

Temperature

80 °C

To a stirred suspension of 2,2-difluoro-4-methyl-7-nitro-4H-1,4-benzoxazin-3-one (Step 1, 1.3 g, 5.32 mmol) in EtOH (20 mL) and water (10 mL) is added ammonium chloride (2.85 g, 53.32 mmol). To this mixture is added iron (892 mg, 15.09 mmol) in 3 equal portions. The resulting mixture is heated to 80° C. for 2 h at which time the reaction is cooled to room temperature followed by addition of CH2Cl2 (50 mL). The resulting mixture is filtered through celite and the filtrate is further diluted with water (50 mL). The organic layer is separated followed by further extraction of the aqueous phase with CH2Cl2 (50 mL×3). The combined organic phase is dried over Na2SO4 and concentrated under reduced pressure, and the residue is purified by passing it through a short silica gel column with EtOAc to give the title compound (1.05 g, Quant.), MS (m/z): 215.5 [M+H]+.

1. temperatureis cooled to room temperature
2. filtrationThe resulting mixture is filtered through celite
3. additionthe filtrate is further diluted with water (50 mL)
4. customThe organic layer is separated
5. extractionfollowed by further extraction of the aqueous phase with CH2Cl2 (50 mL×3)
6. dry with materialThe combined organic phase is dried over Na2SO4
7. concentrationconcentrated under reduced pressure
8. customthe residue is purified

ORD record

ord-aa829696a2cd4888a882b87ae3c7a33a

Source dataset

uspto-grants-2005_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06919329B2