Triethylamine → 2-Tert-butoxycarbonylamino-3-[3-(1-{[4-(3-o-tolyl-ureido)-phenyl]-acetyl}-pyrrolidin-2-yl)-isoxazol-5-yl]-propionic acid

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Reaction Steps

A solution of 1-(4-{2-[2-(hydroxyimino-methyl)-pyrrolidin-1-yl]-2-oxo-ethyl}-phenyl)-3-o-tolyl-urea (300 mg, 0.789 mmol), 2-tert-butoxycarbonylamino-pent-4-ynoic acid methyl ester (359 mg, 1.182 mmol, crude mixture) and triethyl amine (12.9 μL) in dichloromethane (2 mL) was stirred 5 minutes. A sodium hypochlorite solution (5.25%, 2 mL) was added. The reaction was stirred at room temperature overnight. The aqueous portion was extracted 4 times with dichloromethane. The combined organic portions were washed with brine, dried over magnesium sulfate and concentrated. Chromatography of the crude mixture on a Biotage Flash 40S column eluting with ethyl acetate/hexane 1:5 gave the title compound (66 mg, 14%). MS (Cl) m/z 604.5 (M−1), 505.9 (M−99) C. 2-tert-Butoxycarbonylamino-pent-4-ynoic acid methyl ester

Provenance & Evidence