Following the general procedure 20E, 1-(cyclopropylmethyl)-2-(4-ethoxybenzyl)-1H-benzimidazole-5-carboxylic acid (80 mg, 0.228 mmol) was dissolved in DMF (2 mL) and then HATU (104 mg, 0.274 mmol) was added followed by DIPEA (48 μL, 0.274 mmol), After being stirred for 10 min, pyrrolidine (0.456 mmol) was added and the resulting mixture was stirred overnight. The crude residue after work-up was purified by silica gel column chromatography to give pure product which was treated with 1 M HCl solution in diethyl ether to form a HCl salt as white solids (82 mg, 79%). 1H N (400 MHz, CD3OD): δ 7.85 (s, 1H), 7.59 (d, J=8.6 Hz, 1H), 7.48 (d, J=8.6 Hz, 1H), 7.18 (d, J=8.1 Hz, 2H), 6.87 (d, J=8.1 Hz, 2H), 4.32 (s, 2H), 4.07 (d, J=6.8 Hz, 2H), 4.00 (q, J=7.6 Hz, 2H), 3.64 (t, J=. 7.2 Hz, 2H), 3.53 (t, J=7.2 Hz, 2H), 2.06–1.96 (m, 2H), 1.96–1.85 (m, 2H), 1.36 (t, J=7.6 Hz, 3H), 1.10–1.04 (m, 1H), 0.52–0.46 (m, 2H), 0.34–0.28 (m, 2H). MS (ESI) (M+H)+=404. Anal. Calcd for C25H29N3O2.1.5HCl: C, 65.53; H, 6.71; N, 9.17. Found: C, 65.48; H, 6.77; N, 8.75.
