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 stirring for 10 min; cyclohexylmethyl amine (0.456 mmol) was added and the resulting mixture was stirred overnight. The mixture was diluted with EtOAc (50 mL), washed with saturated NaHCO3 (2×10 mL) and then H2O (2×10 mL), dried over MgSO4, and concentrated to give a crude amide. The crude residue 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 (93 mg, 78%). 1H NMR (400 MHz, CD3OD): δ 7.66 (s, 1H), 7.58 (d, J=8.0 Hz, 1H), 7.30 (d, J=8.0 Hz, 1H), 7.16 (d, J=8.6 Hz, 2H), 6.84 (d, J=8.6 Hz, 2H), 4.30 (s, 2H), 4.10–4.04 (m, 5H), 3.96 (q, J=7.6 Hz, 2H), 3.66–3.54 (m, 1H), 1.90–1.50 (m, 10H), 1.33 (t, J=7.6 Hz, 3H), 1.10–0.98 (m, 1H), 0.50–0.42 (m, 2H), 0.32–0.27 (m, 2H). MS (ESI) (M+H)+=446. Anal. Calcd for C28H35N3O2.2.2HCl: C, 63.96; H, 7.13; N, 7.99. Found: C, 64.11; H, 7.24; N, 7.73.
