反应详情

To a solution of methyl 2-(mesitylmethyl)-1-methyl-1H-benzimidazole-7-carboxylate (1.30 g, 4.0 mmol) in tetrahydrofuran (80 mL) was added a solution of ethyllithium in benzene/cyclohexane (90/10) (0.5 M, 32 mL, 16.1 mmol) dropwise at −78° C. The solution was warmed to room temperature over 1 hr followed by addition of saturated aqueous ammonium chloride solution (20 mL). The mixture was extracted with ethyl acetate (100 mL, three times) and the combined organic layers were washed with brine (100 mL), dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 15-25% ethyl acetate/n-hexane gradient mixture to give the title compound (590 mg, 1.68 mmol, 42%) as a colorless solid. The resulting solid was recrystallized from n-hexane/ethyl acetate to give the title compound (435 mg, 1.24 mmol).

1. extractionThe mixture was extracted with ethyl acetate (100 mL, three times)
2. washthe combined organic layers were washed with brine (100 mL)
3. dry with materialdried over anhydrous sodium sulfate
4. concentrationconcentrated in vacuo
5. customThe residue was purified by silica gel column chromatography
6. washeluting with a 15-25% ethyl acetate/n-hexane gradient mixture