反应详情

Concentrated sulfuric acid (2.50 ml, 90 mmol) was added dropwise over 5 min at 0° C. to a stirred solution of 2-carboethoxy-5-chloro-1-phenylsulfonylindole (7.28 g, 20.0 mmol) in acetic anhydride (10 ml) and dry dichloromethane (50 ml). The resulting tan solution was warmed to RT (room temperature) and after 3 hours was poured onto ice and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with brine, dried (Na2SO4) and evaporated in vacuo to a syrup. Residual acetic anhydride was removed by azeotroping with toluene (3×50 ml), and the residue was crystallized from dichloromethane. The dichloromethane was evaporated in vacuo to give the title compound as a tan powder:

1. additionafter 3 hours was poured onto ice
2. extractionthe mixture was extracted with ethyl acetate
3. washThe ethyl acetate layer was washed with brine
4. dry with materialdried (Na2SO4)
5. customevaporated in vacuo to a syrup
6. customResidual acetic anhydride was removed
7. customby azeotroping with toluene (3×50 ml)
8. customthe residue was crystallized from dichloromethane
9. customThe dichloromethane was evaporated in vacuo