To a solution of 3,5-bis-benzyloxy-pyridine-2-carboxylic acid, 2, (2.36 g, 6.36 mmol) in DMF (20 mL) at room temperature under N2 is added 1-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide (EDCI) (1.83 g, 9.54 mmol) and 1-hydroxybenzo-triazole (HOBt) (0.086 g, 0.64 mmol). The mixture is stirred for 15 minutes after which time glycine tert-butyl ester hydrochloride (1.60 g, 9.54 mmol) and diisopropylethylamine (DIPEA) (3.32 ml, 19.08 mmol) are added. The resulting solution is stirred at room temperature for 48 hours then concentrated under reduced pressure. The resulting brown oil is purified over silica (EtOAc) to afford 3.04 g (99% yield) of the desired compound as a yellow solid. 1H NMR (250 MHz, CDCl3) δ ppm 8.19 (1H, t, J=5.2 Hz), 8.01-8.08 (2H, m), 7.27-7.54 (9H, m), 6.97 (1H, d, J=2.4 Hz), 5.24 (2H, s), 5.13 (2H, s), 4.17 (2H, d, J=5.2 Hz), 1.51 (9H, s). HPLC-MS: m/z 449 [M+H]+.
