反应详情

To a stirred solution of ethyl [4-(5,6-dichloro-2-ethyl-1H-benzimidazol-1-yl)phenyl]acetate (step 3, 1.30 g, 3.4 mmol) in methanol was added 2N aqueous NaOH (3.4 mL) at room temperature. After 1 h, the mixture was concentrated and the residue was diluted in water (200 mL) and the mixture was washed with diethyl ether (100 mL). The aqueous layer was acidified with 2N hydrochloric acid and extracted with ethyl acetate/THF (v/v, 1:1, 300 mL). The organic extract was washed with water (200 mL), brine (200 mL), and dried (MgSO4). Removal of solvent gave 1.02 g (86%) of the title compound as a white powder: 1H-NMR (CDCl3) δ 7.94 (1H, s), 7.56–7.45 (4H, m), 7.26 (1H, s), 3.72 (2H, s), 2.72 (2H, q, J=7.3 Hz), 1.22 (3H, t, J=7.5 Hz).

1. concentrationthe mixture was concentrated
2. additionthe residue was diluted in water (200 mL)
3. washthe mixture was washed with diethyl ether (100 mL)
4. extractionextracted with ethyl acetate/THF (v/v, 1:1, 300 mL)
5. extractionThe organic extract
6. washwas washed with water (200 mL), brine (200 mL)
7. dry with materialdried (MgSO4)
8. customRemoval of solvent