A suspension of 2-(3-(4-(1H-indazol-5-ylamino)quinazolin-2-yl)phenoxy)acetic acid (50 mg, 0.098 mmol), PyBOP® (28 mg, 0.054 mmol), DIEA (17 μL, 0.098 mmol) in dry CH2Cl2:DMF (2:0.1 mL) was stirred at RT for 15 minutes. To this solution of activated acid was added (S)-tert-butyl 3-aminopyrrolidine-1-carboxylate (16 mg, 0.084 mmol). After 30 minutes, 1.0 equivalent of DIEA and 0.55 equivalent of PyBOP® were added. After stirring the solution for 15 minutes, 0.65 equivalent of (S)-tert-butyl 3-aminopyrrolidine-1-carboxylate were added and the mixture was stirred for an additional 30 minutes. The solvent was removed in vacuo to afford the crude (3S)-tert-butyl 3-(2-(3-(4-(1H-indazol-5-ylamino)quinazolin-2-yl)phenoxy)acetamido)pyrrolidine-1-carboxylate.
