To a microwave vial containing a solution of Boc-L-glutamic acid tert-butyl ester (0.165 mmol, 1.0 equiv) and HATU (0.165 mmol, 1.0 equiv) in DMF (1.65 mL) was added the amine followed by DIPEA (57.5 μL, 2.0 equiv). The vial was sealed and heated under microwave irradiation for 30 min at 120 °C. Upon completion, the reaction was partitioned between water and CH2Cl2, extracted 3× with CH2Cl2, dried over anhydrous Na2SO4, and concentrated under vacuum. Compounds were purified via reverse phase chromatography (5-95% acetonitrile/water) to afford the N-Boc-glutamylanilide-tert-butyl esters. The compounds were transferred to vials followed by the addition of 2.0 mL of 4.0 M HCl in dioxane. The reaction stirred at 40 °C for 4 h. The reactions were concentrated under vacuum to afford L-Glutamic acid γ-(4-nitroanilide).
