Ethyl Acetate → tert-Butyl{(1R)-2-[(2-oxo-2,3-dihydro-1H-benzimidazol-5-yl)oxy]-1-phenylethyl}carbamate

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Reaction Steps

tert-Butyl [(1R)-2-(3,4-diaminophenoxy)-1-phenylethyl]carbamate (Intermediate 6) (318 mg, 0.93 mmol) was placed in a 50-mL RBF under a nitrogen atmosphere and dissolved in DMF (5 mL). CDI (135 mg, 0.83 mmol) was added, and the reaction was stirred at room temperature for four hours. The reaction was added to a separatory funnel containing ethyl acetate (125 mL) and dilute aqueous NaHCO3 (75 mL); the phases were separated, and the organic layer was washed with brine (75 mL), dried over anhydrous Na2SO4 and then concentrated in vacuo. The crude product mixture was then purified by silica gel chromatography to afford tert-butyl {(1R)-2-[(2-oxo-2,3-dihydro-1H-benzimidazol-5-yl)oxy]-1-phenylethyl}carbamate as a white solid. 1H NMR (500 MHz, C2D6SO) δ 10.49 (s, 1H), 10.37 (s, 1H), 7.54 (d, 1H), 7.34 (m, 4H), 7.25 (t, 1H), 6.77 (d, 1H), 6.48 (s, 2H), 4.86 (q, 1H), 3.98 (m, 2H), 1.37 (s, 9H). LRMS (ESI) calc'd for (C16H16N3O4) [M−C4H8+H]+, 314.1; found 314.1.

Provenance & Evidence