Propanoic acid, 2-bromo-2-methyl-, ethyl ester → 2,2-Dimethyl-7-nitro-2H-benzo[b][1,4]oxazin-3(4H)-one

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Reaction Steps

To a suspension of potassium fluoride (4.71 g) in N,N-dimethylformamide (40 mL) was added 2-amino-5-nitrophenol (5.00 g), and the mixture was stirred at room temperature for 1 hour. To the suspension was added dropwise a solution of ethyl α-bromoisobutyrate (6.33 g) in N,N-dimethylformamide (10 mL) over a period of 20 minutes, and the mixture was stirred at 60° C. for 20 hours. After cooling, to the reaction mixture was added cool, water and the mixture was extracted with ethyl acetate. The organic layer was washed successively with an aqueous 10% HCl solution, water and brine, dried over sodium sulfate and concentrated in vacuo. The resultant residue was suspended in ethyl acetate, and the precipitates were collected by filtration and washed with ethyl acetate to give 2,2-dimethyl-7-nitro-2H-1,4-benzoxazin-3(4H)-one (2.80 g) as a pale brown powder.

Provenance & Evidence