Sulfuric Acid → HCID 18351863, compound

Methyl 7-methoxy-2-methyl-3-oxo-2,3-dihydrobenzofuran-2-carboxylate (18.38 g) was dissolved in dioxane-water (5:1, 300 ml) and 0.5 N sulfuric acid (37 ml) was added to the solution, followed by refluxing the resulting solution for 16 hours. The reaction solution was concentrated and poured into water layer (300 ml), followed by extracting the resultant three times with ether (150 ml). The organic layers were combined and washed with saturated aqueous sodium hydrogen carbonate solution and with saturated brine, followed by drying over sodium sulfate. After removing the sodium sulfate by filtration, the solvent was removed under reduced pressure and the residue was purified by column chromatography (solvent: hexane/ethyl acetate=9/1-5/1) using florisil to obtain the desired compound (4.69 g, yield: 36%).

1. temperatureby refluxing the resulting solution for 16 hours
2. concentrationThe reaction solution was concentrated
3. additionpoured into water layer (300 ml)
4. extractionby extracting the resultant three times with ether (150 ml)
5. washwashed with saturated aqueous sodium hydrogen carbonate solution and with saturated brine
6. dry with materialby drying over sodium sulfate
7. customAfter removing the sodium sulfate
8. filtrationby filtration
9. customthe solvent was removed under reduced pressure
10. customthe residue was purified by column chromatography (solvent: hexane/ethyl acetate=9/1-5/1)

ORD record

ord-034428a804b94b0ca28b57d4a9d60276

Source dataset

uspto-grants-2001_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06323235B1