反应详情

A dry 2-neck 500 mL round-bottom flask (RBF) was charged with sodium ethanolate (46.2 mL, 124 mmol), diluted with 151 mL absolute EtOH, cooled in an ice bath and treated dropwise with diethyl malonate (17.98 mL, 118 mmol) under an atmosphere of nitrogen. After stirring for 20 minutes, the ice bath was removed and 3-chlorobenzo[d]isothiazole (20.0 g, 118 mmol) was added in one portion and stirred for 24 hours. The reaction solution was quenched with water, extracted with ether and treated with excess 4 M HCl/dioxane. A pinkish-white precipitate was filtered off, suspended in water, basified with Na2CO3, extracted with ether, washed with water and brine, dried over sodium sulfate, filtered and concentrated to yellow solids (˜20 g) which were recrystallized from ethanol/water and dried in a vacuum oven at 60° C. for 3 hrs to give ethyl 3-aminobenzo[b]thiophene-2-carboxylate (19.9 g, 76% yield).

1. temperaturecooled in an ice bath
2. customthe ice bath was removed
3. stirringstirred for 24 hours
4. customThe reaction solution was quenched with water
5. extractionextracted with ether
6. additiontreated with excess 4 M HCl/dioxane
7. filtrationA pinkish-white precipitate was filtered off
8. extractionextracted with ether
9. washwashed with water and brine
10. dry with materialdried over sodium sulfate
11. filtrationfiltered
12. concentrationconcentrated to yellow solids (˜20 g) which
13. customwere recrystallized from ethanol/water
14. customdried in a vacuum oven at 60° C. for 3 hrs