反应详情

温度

-78 °C

In an oven dried nitrogen purged 3 neck 50 mL round bottom flask, 0.500 g (1.75 mmol) of 5-methoxy-1-methylbenzimidazole in 10 mL of dry THF is cooled to −78° C. 2.47 mL (4.20 mmol) of 1.7 M t-butyllithium in hexanes is added and the reaction mixture is stirred at −78° C. for 1 h. 0.472 g (2.1 mmol) of NIS in 10 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 3×50 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 0.125 g of the title compound, 25% yield. MS, ES+=289.0 (M+1); 1H NMR (DMSO-d6) δ 7.439-7.417 (d, 1H); 7.147-7.141 (m, 1H); 6.771-6.743 (m, 1H); 3.794 (s, 3H); 3.707 (s, 3H) ppm.

1. customReaction
2. customis removed from bath
3. stirringstirred at room temperature for 1 hour
4. customquenched with saturated aqueous solution of ammonium chloride
5. additiondiluted with dichloromethane
6. customThe layers are separated
7. extractionthe aqueous is extracted 3×50 mL dichloromethane
8. dry with materialdried (MgSO4)
9. concentrationconcentrated
10. customThe crude mixture is purified by chromatography
11. additionThe product containing fractions