Water → Trans-N-Boc-2-(4-chlorophenyl)-3-(isopropylamino) acrylic acid

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Reaction Steps

(E)-ethyl 3-((tert-butoxycarbonyl)(isopropyl)amino)-2-(4-chlorophenyl)acrylate (133.5 kg, 362.9 mol) was added into a mixture of H2O (252 L), NaOH (58.25 kg, 1456 mol) and EtOH (383.5 L) stirred at room temperature. The mixture was warmed to 40-45° C. for 2.5 h until a clear solution was formed. The mixture was concentrated to a minimum working volume maintaining the temperature below 50° C. The mixture was then cooled to 10-25° C. and a solution of HCl was added (842 L of 2N HCl and 11 L of 35% HCl) until a final pH=2˜4 was obtained. The aqueous layer was separated and the organic layer was washed with 25% aqueous NaCl (810 L). n-Heptane was added while distilling to form a suspension. The product was collected and washed with n-heptane and dried at 40-45° C. for ˜10 h to afford 110.7 kg (90.5% yield) of (E)-3-(tert-butoxycarbonyl(isopropyl)amino)-2-(4-chlorophenyl)acrylic acid having 99.9 A % purity by HPLC. E-configuration was confirmed using single crystal x-ray analysis (See FIG. 1).

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