1-Hydroxybenzotriazole → 2-[(5-Phenyl-1,2-oxazol-3-yl)formamido]acetic acid

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Reaction Steps

To a stirred solution of 5-phenyl-isoxazole-3-carboxylic acid (1 g, 0.00529 mol) in DMF (5 mL) was added DIPEA (2.73 g, 0.0211 mol), HOBt (0.89 g, 0.006078 mol) and EDCI.HCl (1.266 g, 0.00661 mol) at ambient temperature. After 2 minutes glycine ethyl ester hydrochloride (0.811 g, 0.00581 mol) was added and the resulting mixture was stirred at ambient temperature overnight. The reaction mixture was diluted with cold water and the resulting precipitate was isolated by filtration and dried to afford 0.744 g (56%) of 5-phenyl-isoxazole-3-carbonyl)-amino]-acetic acid ethyl ester. LCMS: 275.1 (M+1)+, 94%. To a stirred solution of [(5-phenyl-isoxazole-3-carbonyl)-amino]-acetic acid ethyl ester (0.74 g, 0.00270 mol) in a mixture of THF (5 mL), methanol (5 mL) and H2O (5 mL) was added LiOH.H2O (0.34 g, 0.00809 mol) and the resulting mixture was stirred at ambient temperature for 1 hour. Volatiles were then evaporated and the resulting residue was diluted with water and acidified with concentrated HCl. The resulting precipitate was isolated by filtration and dried to afford 0.57 g (76%) of [(5-phenyl-isoxazole-3-carbonyl)-amino]-acetic acid. LCMS: 247.06 (M+1)+, 98.18%.

Provenance & Evidence