Acetic Acid → (Z)-ethyl 3-(2-(tert-butoxycarbonylamino)ethylamino)-3-(2,4-dimethoxyphenyl)acrylate

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Reaction Steps

A solution of ethyl 3-(2,4-dimethoxyphenyl)-3-oxopropanoate (41.91 g, 166 mmol), tert-butyl 2-aminoethylcarbamate (54.7 g, 342 mmol), and acetic acid (16.14 g, 269 mmol) in ethanol (180 mL) was heated at reflux for 5.3 h. After removal of most of the solvent by rotary evaporation, the resulting oil was partitioned between EtOAc (ca. 300 mL) and 10% (w/v) aq. ammonium chloride. The EtOAc layer was separated and then washed with water, 10% (w/v) aq. ammonium chloride (3 mL), and brine (10 mL). The EtOAc layer was washed with sat. aq. sodium bicarbonate, brine (6 mL) was added, and the emulsion was allowed to settle. The EtOAc layer was finally washed with brine and dried over sodium sulfate. Evaporation of the EtOAc layer's volatile components afforded a viscous, amber taffy (62.3 g, 95%). This crude product was used without further purification.

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