Hydrochloric Acid → 3-(4-(3-(2-Fluorophenyl)ureido)phenyl)isoxazole-5-carboxylic acid

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Reaction Steps

3-{4-[3-(2-Fluoro-phenyl)ureido]-phenyl}-isoxazole-5-carboxylic acid ethyl ester (4.6 g) was dissolved in THF (92 ml). 1M aqueous NaOH solution (65 ml) was added and stirred at RT for 15-20 minutes. The reaction mixture was acidified with dilute HCl and extracted with EtOAc. Organic layer was separated, dried over Na2SO4 and concentrated under reduced pressure to get off white solid, which was crystallized from CH2Cl2 to yield 3.68 g (86%) white solid. MS (ES+): m/z 342 (M+1); 1HNMR (DMSO-d6, 300 MHz): δ 9.33 (s, 1H), 8.63 (s, 1H), 8.13 (m, 1H), 7.89 (d, 2H), 7.7 (s, 1H), 7.6 (d, 2H), 7.23 (m, 1H), 7.13 (m, 1H), 7.02 (m, 1H).

Provenance & Evidence