3-Hydroxy-5-(2-oxopyrrolidin-1-yl)benzoic acid → (2R,4R)-tert-butyl 2-((1S,2S)-1-(tert-butyldimethylsilyloxy)-3-(3,5-difluorophenyl)-2-(3-hydroxy-5-(2-oxopyrrolidin-1-yl)benzamido)propyl)-4-propoxypyrrolidine-1-carboxylate

Beteiligte Stoffe

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Reaktionsschritte

Step I (4): 3-Hydroxy-5-(2-oxopyrrolidin-1-yl)benzoic acid. To a solution of 3-amino-5-(2-oxopyrrolidin-1-yl)benzoic acid (Step I (3), 140 mg, 0.63 mmol) in 2N HCl (2 mL) were added MeOH (2 mL) followed by NaNO2 (88 mg, 1.26 mmol) in portions at −10° C. After the mixture was warmed up to 0° C., H2O (3 mL) was added to the above mixture and the mixture was stirred at 95° C. for 1 h. 0.1N HCl (30 mL) was added and the mixture was extracted with ethyl acetate (50 mL) three times. The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo to give 130 mg of the title compound: 1H NMR (CD3OD, 500 MHz) δ ppm 2.19 (2H, m), 2.62 (2H, m), 3.94 (2H, m), 7.27 (1H, m), 7.47 (1H, m), 7.66 (1H, m). MS (ESI) (M−H)− 220.12.

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