To a solution of 2-(3,5-dichlorophenylamino)acetic acid (153 mg, 0.69 mmol) in DMF (5 mL) was added HOBt (141 mg, 1.0 mmol), EDCI (201 mg, 1.0 mmol), tert-butyl 4-methylpiperidin-3-ylcarbamate (150 mg, 0.69 mmol), and DIEA (0.18 mL, 1.3 mmol) at 0° C. Then the reaction mixture was stirred at rt for 5 h, partitioned between EtOAc and water. The organic phase was separated and washed with brine, and concentrated in vacuo to yield the crude product, which was purified by column chromatography using 0-2% MeOH: DCM solvent mixture to yield the titled intermediate (160 mg, 54%) as a thick liquid. 1H NMR (400 MHz, CDCl3): δ 6.92 (s, 1H), 6.49 (s, 1H), 6.38 (s, 1H), 6.29 (s, 1H), 5.22-5.15 (m, 1H), 4.65-4.56 (m, 1H), 4.35-4.16 (m, 2H), 3.25-2.89 (m, 2H), 2.85-2.69 (m, 2H), 1.82-1.75 (m, 2H), 1.69-1.45 (m, 1H), 1.22 and 1.14 (2s, 9H), 1.05 and 0.95 (2d, J=6.8 Hz, 3H). LC-MS: m/z [M+1]=416.
