反应详情

温度

-78 °C

Methyl 2-allyl-3-hydroxy-4-nitro-benzoate 1d (5.39 g, 22.70 mmol) was dissolved in 110 mL of the mixture solvent of dichloromethane and methanol (V/V=10:1), the reaction solution was cooled down to −78° C. and filled with oxone. After stirring for 50 minutes, oxone was removed from filling with. The reaction mixture was stirred for another 20 minutes, then filled with argon and stirred for 10 minutes. Triphenyl phosphine (17.80 g, 68.10 mmol) was added. After removing the dry ice bath, the resulting mixture was allowed to room temperature and stirred for 3 hours. The reaction solution was concentrated under reduced pressure, added with 200 mL of ethyl acetate, washed with water (100 mL×3) and saturated sodium chloride solution (100 mL×3) successively, then dried over anhydrous magnesium 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 2-hydroxy-7-nitro-2,3-dihydrobenzofuran-4-carboxylate 1e (5.20 g, yield: 96.0%) as a brown solid.

1. customoxone was removed
2. stirringThe reaction mixture was stirred for another 20 minutes
3. additionfilled with argon
4. stirringstirred for 10 minutes
5. customAfter removing the dry ice bath
6. customwas allowed to room temperature
7. stirringstirred for 3 hours
8. concentrationThe reaction solution was concentrated under reduced pressure
9. additionadded with 200 mL of ethyl acetate
10. washwashed with water (100 mL×3) and saturated sodium chloride solution (100 mL×3) successively
11. dry with materialdried over anhydrous magnesium sulfate
12. filtrationfiltered
13. concentrationthe filtrate was concentrated under reduced pressure
14. customThe resulting residue was purified by silica gel column chromatography