Ethyl chloroformate → [1-(4-Benzyloxy-3-methoxy-phenyl)-2-phenyl-ethyl]-(2,2-dimethoxy-ethyl)-carbamic acid ethyl ester

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Reaction Steps

To a stirred solution of [1-(4-benzyloxy-3-methoxy-phenyl)-2-(3-methoxy-phenyl)-ethyl]-(2,2-dimethoxy-ethyl)-amine (10.46 g, 20 mmol) in tetrahydrofuran (40 mL) and water (20 mL) was added potassium carbonate (5 g, 36 mmol) and ethyl chloroformate (1.91 mL, 20 mmol) dropwise. The mixture was stirred for 1 h at room temperature. The mixture was diluted with diethyl ether (100 mL), and the organic layer was separated. The aqueous phase was extracted with ethyl acetate (3×100 mL) and the combined extracts were washed with saturated aqueous sodium chloride solution (100 mL), dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 70–230 mesh, 20% ethyl acetate/hexane) afforded [1-(4-benzyloxy-3-methoxy-phenyl)-2-phenyl-ethyl]-(2,2-dimethoxy-ethyl)-carbamic acid ethyl ester (7 g, 67% yield in three steps) as a colorless oil.

Provenance & Evidence