4-(2-Aminoethyl)benzoic acid → 4-(2-{[(Tert-butoxy)carbonyl]amino}ethyl)benzoic acid

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Reaction Steps

tert-Butyl dicarbonate (1.64 g; 7.5 mmol) is dissolved in 1,4-dioxane (5 mL) and the solution is added to a well-stirred solution of 4-(2-aminoethyl)benzoic acid (1.0 g; 5 mmol) in 1M aqueous sodium hydroxide solution (25 mL) and 1,4-dioxane (10 mL), and the mixture is then stirred at ambient temperature for 3 hours. The 1,4-dioxane is removed by evaporation in vacuo, and then ethyl acetate (200 mL) is added to the residue. The pH of the aqueous phase is adjusted to 1.5 with 2M aqueous HCl solution. The organic phase is separated off and the aqueous phase is then extracted with ethyl acetate (100 mL). The combined organic extracts are washed with water, dried over Na2SO4 and evaporated to a volume of 10 mL. Heptane is added to the residue and then the solid precipitate is filtered off to yield the title compound.

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