Hydrochloric Acid → 6-(2-Chlorophenylamino)-7-fluoro-3-methylbenzo[c]-isoxazole-5-carboxylic acid

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Reaction Steps

To a solution of 6-(2-chlorophenylamino)-7-fluoro-3-methyl-benzo[c]-isoxazole-5-carboxylic acid methyl ester (55) (100 mg, 0.299 mmol) in 6:1 THF:water (3.5 mL) was added LiOH (0.60 ml of a 1 M solution in water). After 1 hour, the reaction was acidified to pH 1 with 1 N HCl, diluted with water and extracted with EtOAc. The combined organic extracts were washed with water, dried (MgSO4) and concentrated to give the desired product (56) (87 mg, 91%). MS APCI (−) m/z 319, 321 (M+, Cl pattern) detected: 1H NMR (400 MHz, CD3OD) δ 8.45 (s, 1H), 7.38 (dd, 1H), 7.20 (m, 1H), 6.91 (m, 2H), 2.88 (s, 3H): 19F NMR (376 MHz, CD3OD) −136.40 (s, 1F).

Provenance & Evidence