Trifluoroacetic acid → 2-Butylaminomethylbenzimidazole

Participants

Reaction Steps

To a stirred solution of 1-BOC-2-bromomethylbenzimidazole (2.00 g, 6.4 rnmol) in dry THF (20 mL) was added n-butylamine (1.2 g, 15.4 mmol). After stirring at RT overnight, the mixture was concentrated. The residue was taken up in H2O and extracted with CH2Cl2. The organic extracts were dried over MgSO4 and concentrated to give a brown residue, which was dissolved in CH2Cl2 (15 mL) and treated with TFA (5 mL). The resulting mixture was stirred at RT overnight then was concentrated. The residue was taken up in H2O, and the solution was neutralized with 2.5 N NaOH. CH2Cl2 extraction, drying (MgSO4), concentration, and silica gel chromatography (2% MeOH/CH2Cl2) gave the title compound as a yellow oil (0.91 g, 70%): 1H NMR (250 MHz, CDCl3) δ 0.79 (t, J=7.2 Hz, 3H), 1.23 (m, 2H), 1.54 (m, 2H), 3.35 (t, J=7.2 Hz, 2H), 4.55 (s, 2H), 7.25 (m, 2H), 7.48 (m, 1H), 7.75 (m, 1H).

Provenance & Evidence