Ammonia → 3-(4-Carbamoyl-2-ethyl-6-methylphenyl)propionic acid tert-butyl ester

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Reaction Steps

To a solution of 4-(2-tert-butoxycarbonyl-ethyl)-3-ethyl-5-methyl-benzoic acid (36.0 g, 123 mmol) in isopropanol (400 mL), HOBT (18.3 g, 135 mmol) followed by EDC HCl (27.1 g, 142 mmol) is added. The mixture is stirred at rt for 1 h before aq. ammonia (69 mL of 25% solution) is added. Stirring is continued for 1 h before the mixture is diluted with DCM (500 mL) and washed with half sat. aq. NaHCO3 solution (3×400 mL), followed by water (400 mL). The org. extract is dried over MgSO4, filtered and concentrated. The crude product is trituated with TBME 8250 mL). The solid material is collected, washed with additional TBME (50 mL) and dried under high vacuum to give 3-(4-carbamoyl-2-ethyl-6-methyl-phenyl)-propionic acid tert-butyl ester (31.91 g) as a white solid.

Provenance & Evidence