反应详情

温度

-75 °C

An amount of 2.9 g (7.0 mmol) of 2-(tert-butyl-dimethyl-silanyl)-4-(2,3-difluoro-benzyl)-imidazole-1-sulfonic acid dimethylamide was dissolved in 30 ml tetrahydrofuran and added drop-wise to a freshly prepared solution of lithium diisopropylamide in tetrahydrofuran (from 6.54 ml 1.6M BuLi and 1.06 g diisopropylamine). After stirring for 1 h at −75° C., 1.14 g (8.0 mmol) methyl iodide was added, and stirring was continued overnight at ambient temperature. Water was added to quench the reaction. The aqueous phase was extracted with ethyl acetate (3 times) and the combined organic extracts were dried over MgSO4, filtered and concentrated. The residue was purified by flash chromatography (silica gel, hexanes/ethyl acetate 4:1) to yield 2.47 g of rac-2-(tert-butyl-dimethyl-silanyl)-4-[1-(2,3-difluoro-phenyl)-ethyl]-imidazole-1-sulfonic acid dimethylamide (MS (ISP): 430.3 ((M+H)+.), light yellow oil). This material was separated by chiral column chromatography (Chiral OD, isopropanol/heptane=2:98) to yield 0.785 g (26%) of (+)-2-(tert-butyl-dimethyl-silanyl)-4-[1-(2,3-difluoro-phenyl)-ethyl]-imidazole-1-sulfonic acid dimethylamide and 0.946 g (32%) of (+)-2-(tert-butyl-dimethyl-silanyl)-4-[1-(2,3-difluoro-phenyl)-ethyl]-imidazole-1-sulfonic acid dimethylamide.

1. stirringstirring
2. waitwas continued overnight at ambient temperature
3. customto quench
4. customthe reaction
5. extractionThe aqueous phase was extracted with ethyl acetate (3 times)
6. dry with materialthe combined organic extracts were dried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was purified by flash chromatography (silica gel, hexanes/ethyl acetate 4:1)