反应详情

Methyl 2-hydroxy-7-nitro-2,3-dihydrobenzofuran-4-carboxylate 1e (2 g, 8.40 mmol) was suspended in 250 mL of 85% phosphoric acid, stirred for 10 minutes, puted into a 100° C. oil bath and stirred for another 20 minutes. The resulting reaction mixture was added with 50 mL of water, extracted with ethyl acetate (50 mL×3). The combined organic phase was washed with saturated sodium carbonate solution (50 mL×3) and saturated sodium chloride solution (50 mL×3) successively, then dried over anhydrous sodium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound methyl 7-nitrobenzofuran-4-carboxylate 1f (0.63 g, yield: 34.0%) as a light yellow solid.

1. customputed into a 100° C.
2. stirringstirred for another 20 minutes
3. customThe resulting reaction mixture
4. extractionextracted with ethyl acetate (50 mL×3)
5. washThe combined organic phase was washed with saturated sodium carbonate solution (50 mL×3) and saturated sodium chloride solution (50 mL×3) successively
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationthe filtrate was concentrated under reduced pressure
9. customThe resulting residue was purified by silica gel column chromatography