2,4-Dioxo-2,4-dihydro-1H-benzo[D][1,3]oxazine-6-carboxylic acid → 4-Amino-3-(methoxycarbonyl)benzoic acid

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Reaction Steps

150 mg (1.21 mmol) of 4-dimethylaminopyridine are added to 2.5 g (12.1 mmol) of 2,4-dioxo-1,4-dihydro-2H-3,1-benzoxazine-6-carboxylic acid [described in J. Med. Chem., (1981), 24(6), 735-742] in solution in 10 ml of dimethylformamide and 10 ml of methanol, and the mixture is heated at 60° C. for 3 hours. The reaction medium is concentrated under reduced pressure. The residue is taken up in water and extracted with ethyl acetate. The organic phase is washed with a saturated sodium chloride solution, dried over sodium sulphate and concentrated under reduced pressure. The solid obtained is taken up in ethyl acetate, filtered and dried. 1.98 g of a white powder are obtained.

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