反应详情

A solution of 1-(2-hydroxyethyl)-1H-benzimidazole-7-carbonitrile (0.29 g, 1.5 mmol) in dry THF (6.2 ml) is cooled to −78° C. and MeLi (5.8 mL, 9.3 mmol) is added slowly. After the addition the reaction mixture is allowed to warm up to ambient temperature and kept such for 30 min. The temperature is brought down to −78° C. again and water (4 ml) was added slowly. After warming up the reaction mixture is acidified to pH 4 and heated at 50° C. for 30 min. Solvents are removed under reduced pressure and the residue is partitioned between ethyl acetate and aq. NaHCO3. The organic extract is further washed with water and brine, dried over Na2SO4 and concentrated. Purification is performed on flash silica column using ethyl acetate-methanol as the eluent to give the desired product (0.25 g, 80%).

1. additionAfter the addition the reaction mixture
2. customis brought down to −78° C.
3. temperatureAfter warming up the reaction mixture
4. temperatureheated at 50° C. for 30 min
5. customSolvents are removed under reduced pressure
6. customthe residue is partitioned between ethyl acetate and aq. NaHCO3
7. extractionThe organic extract
8. washis further washed with water and brine
9. dry with materialdried over Na2SO4
10. concentrationconcentrated
11. customPurification