反应详情

A 1 L 3-neck round bottom flask equipped with a magnetic stirrer, thermometer, dropping funnel and nitrogen bubbler was charged with 12.97 g (46.9 mmol) of 2-[2-(1H-tetrazol-5-yl)phenyl]-5-methylbenzofuran and 500 mL of 1,4-dioxane. To the well-stirred solution at room temperature was added a solution of 4.8 mL (93.2 mmol) of bromine in 35 mL of carbon tetrachloride dropwise over 1 hour. Cyclohexene (16 mL) was added to the reaction mixture then it was concentrated under vacuum to an oily residue that was partitioned between 100 mL of 1N aqueous sodium hydroxide and 100 mL of ether. The aqueous layer was removed, acidified with 50 mL of 2N aqueous hydrochloric acid, and extracted several times with ethyl acetate. The combined extracts were washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated under vacuum to give a white foam that was triturated with 100 mL of hot toluene. The mixture was cooled in an ice bath and the solids removed by filtration then washed with cold toluene, air dried and dried under vacuum to give 14.11 g (39.7 mmol,85%) of product. 1H NMR (200 MHz,CDCl3 +1 drop DMSO-d6)2.44 (s,3H), 7.1-7.3(m,4H), 7.6 (m,2H), 7.86 (m,1H), 7.95 (m,1H).

1. customA 1 L 3-neck round bottom flask equipped with a magnetic stirrer
2. concentrationit was concentrated under vacuum to an oily residue that
3. customwas partitioned between 100 mL of 1N aqueous sodium hydroxide and 100 mL of ether
4. customThe aqueous layer was removed
5. extractionextracted several times with ethyl acetate
6. washThe combined extracts were washed with saturated aqueous sodium chloride
7. dry with materialdried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated under vacuum
10. customto give a white foam that
11. customwas triturated with 100 mL of hot toluene
12. temperatureThe mixture was cooled in an ice bath
13. customthe solids removed by filtration
14. washthen washed with cold toluene, air
15. customdried
16. customdried under vacuum