1H-Benzimidazole, 1-methyl- → 2-Iodo-1-methyl-1H-benzoimidazole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In an oven dried nitrogen purged 3 neck 100 mL round bottom flask, 1.00 g (7.57 mmol) of 1-methylbenzimidazole in 20 mL of dry tetrahydrofuran is cooled to −78° C. 10.69 mL (18.17 mmol) of 1.7 M t-butyllithium in hexanes is added and the reaction mixture is stirred at −78° C. for 1 h. 2.55 g (11.36 mmol) of NIS in 20 mL of dry tetrahydrofuran is added. Reaction is removed from bath and stirred at room temperature for 1 hour, quenched with saturated aqueous solution of ammonium chloride, and diluted with dichloromethane. The layers are separated, the aqueous is extracted 3×100 mL dichloromethane, dried (MgSO4), and concentrated. The crude mixture is purified by chromatography using hexanes:ethyl acetate as a solvent system. The product containing fractions are combined to obtain 0.400 g of the title compound, 21% yield. MS, ES+=259.0 (M+1); 1H NMR (DMSO-d6) δ 7.580-7.552 (m, 2H); 7.228-7.129 (m, 2H); 3.750 (s, 3H) ppm.

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