反应详情

A solution of 2-(tert-butyl-dimethyl-silanyl)-imidazole-1-sulfonic acid dimethylamide (1.0 g) in THF (10 ml) was cooled under an Argon atmosphere to −78° C. n-Buthyllithium solution (1.6 M in heptane, 2.37 ml) were added dropwise. After stirring for 1 hr at −78° C. a solution of 7-formyl-5-methyl-benzofuran-2-carboxylic acid ethyl ester (963 mg) in THF (10 ml) was added dropwise. Stirring was continued for 15 min at −78° C., then the reaction mixture was warmed up to r.t. overnight. After quenching with water, the mixture was extracted with EtOAc. The organics were dried over MgSO4, filtrated and concentrated. The crude product was purified by column chromatography (silica gel; gradient: cyclohexane→cyclohexane/EtOAc 1:1) to give rac-7-{[2-(tert-butyl-dimethyl-silanyl)-1-dimethylsulfamoyl-1H-imidazol-4-yl]-hydroxy-methyl}-5-methyl-benzofuran-2-carboxylic acid ethyl ester as light yellow amorphous solid; MS (ISP): 522.3 ((M+H)+.).

1. additionwere added dropwise
2. additionwas added dropwise
3. customAfter quenching with water
4. extractionthe mixture was extracted with EtOAc
5. dry with materialThe organics were dried over MgSO4
6. filtrationfiltrated
7. concentrationconcentrated
8. customThe crude product was purified by column chromatography (silica gel; gradient: cyclohexane→cyclohexane/EtOAc 1:1)