Methyl bromoacetate → (3S)-2-Oxo-3-tert-butoxycarbonylamino-2,3,4,5-tetrahydro-1H-1,5-benzodiazepine-1-acetic acid methyl ester

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Reaction Steps

A 1.0 M solution of lithium bis(trimethylsilyl)amide (3.4 ml, 3.4 mmol) in THF was added dropwise to a −78° C. solution of 3-tert-butoxycarbonylamino-1,3,4,5-tetrahydrobenzo[b][1,4]diazepin-2-one (0.94 g, 3.38 mmol) in 20 ml of anhydrous tetrahydrofuran and stirred for 30 minutes. Methyl bromoacetate (o0.44 ml, 4 mmol) was added dropwise to the reaction mixture then warmed to room temperature. The reaction was diluted with 100 ml of ethyl acetate and washed with 0.3N potassium hydrogen sulfate (50 ml), water (2×50 ml), and brine. The combined organics were dried over anhydrous sodium sulfate, filtered, and evaporated to afford a gum that was purified by flash chromatography eluting with 3:7 EtOAc/Hex. to give 0.98 g (83%) of the title compound as a white solid. 1H NMR (CDCl3) δ7.15-7.07 (2H, m), 6.98-6.94 (1H, m), 6.88-6.84 (1H, d), 5.62-5.55 (1H, d), 4.71-4.65 (1H, d), 4.65-4.6 (1H, m), 4.33-4.27 (1H, d), 3.96-3.90 (1H, m), 3.78 (3H, s), 3.44-3.37 (1H, m), 1.4 (9H, s).

Provenance & Evidence