Reaction Steps
To a 20 mL Bohdan MiniBlock 12-position glass reaction tube, 1-{4-[2-(pyridin-2-yloxy)ethoxy]phenyl}-1H-benzimidazole-5-carboxylic acid (100 mg, 0.27 mmol), PS-HOBt (HL; 269 mg, 0.24 mmol), DMAP (18 mg, 0.15 mmol), CH2Cl2 (1 mL), and DMF (0.25 mL) were added. The reaction mixture was shaken for 5 min. 1,3-Diisopropylcarbodiimide (138 mg, 1.09 mmol) was added to the reaction mixture and shaken for 4 h. The solution was filtered and the resin was washed with CH2Cl2 (3×3 mL), DMF (3×3 mL), and THF (3×3 mL). The resin was resuspended in DMF (1 mL) and 2-aminoethanol (15 mg, 0.24 mmol) and DIEA (31 mg, 0.24 mmol) were added. The reaction mixture was allowed to shake overnight. The reaction mixture was then filtered, and washed with CH2Cl2 (3×3 mL), DMF (3×3 mL), and THF (3×3 mL). The filtrate and the washes were combined and concentrated in vacuo. The crude product was purified by using the Waters mass-directed HPLC purification system to yield N-(2-hydroxyethyl)-1-{4-[2-(pyridin-2-yloxy)ethoxy]phenyl}-1H-benzimidazole-5-carboxamide as a yellowish white powder. 1H NMR (d6-DMSO, 400 MHz): δ 8.57 (s, 1H), 8.49 (t, J=4.4 Hz, 1H), 8.32 (d, J=1.2 Hz, 1H), 8.19 (ddd, J=5.2, 2.0, 0.8 Hz, 1H), 7.85 (dd, J=8.4, 1.6 Hz, 1H), 7.74 (ddd, J=9.2, 7.2, 2.0 Hz, 1H), 7.61 (ddd, J=5.6, 3.6, 3.6 Hz, 2H), 7.56 (d, J=8.0 Hz, 1H), 7.23 (ddd, J=6.0, 3.6, 3.6 Hz, 2H), 7.01 (ddd, J=7.2, 5.2, 0.8 Hz, 1H), 6.88 (ddd, J=8.4, 0.8, 0.8 Hz, 1H), 4.63 (m, 2H), 4.43 (m, 2H), 2.82 (d, J=4.8 Hz, 3H). MS(ES+): m/z 419 (60) [MH+].
