Triethylamine → 2-((4-(2-Pyridinyl)-1-piperazinyl)methyl)-1H-benzimidazole

Participants

Reaction Steps

To a rapidly stirred solution of 1-(2-pyridyl)piperazine (5.9 g, 36 mmol) in DMF (15 mL) in a large round bottom flask in a water bath at 20° C. was added 2-chloromethylbenzimidazole powder (6 g, 36 mmol) over 2 minutes. Triethylamine (7.5 mL, 1.5 eq) was added, and the reaction was stirred for 16 hours, until TLC indicated complete consumption of starting material. The reaction was then treated with 5 mL of triethylamine followed by the slow dropwise addition of water (70 mL). After one hour, the precipitate was collected by suction filtration and washed with 400 mL of water and dried to give 9 grams of product. The solid was recrystallized twice from boiling n-butanol to give 7.6 grams (72% yield purified) of the title compound as a buff powder. mp 220–221° C. 1H NMR (d6-DMSO, 300 MHz) δ 2.55 (4H, J=4.5 Hz), 3.52 (4H, J=4.5 Hz), 3.77 (s, 2H), 6.62 (1H, J=6.6, 4.5 Hz), 6.81 (1H, J=8.7 Hz), 7.14 (2H, m), 7.41–7.58 (3H, m), 8.09 (1H, J=4.5, 1.8 Hz), MS (DCI/NH3) m/z 294 (M+H)+. Anal. Calcd for C17H19N5: C, 69.60; H, 6.53; N, 23.87. Found: C, 69.47; H, 6.58; N, 23.87.

Provenance & Evidence