Sodium hydride → 3,5-dimethyl-6-(5-formylbenzofuran-2-yl)-4-hydroxy-2H-pyran-2-one

Temperatur

-78 °C

A solution of methyl 2-methyl-3-oxopentanoate (7.5 g) in THF (50 ml) was slowly added to a suspension of NaH (2.1 g) in THF (200 ml), and after stirring for 10 minutes, the mixture was cooled to −78° C. and 1.58 M n-BuLi (32 ml) was slowly added dropwise. After stirring the reaction solution at −78° C. for 30 minutes, a solution of methyl 5-(dimethoxymethyl)benzofuran-2-carboxylate (10 g) in THF (50 ml) was slowly added and the mixture was stirred at −78° C. for 4 hours. A saturated ammonium chloride aqueous solution (30 ml) was added to the reaction solution, and after bringing it to room temperature, extraction was performed with AcOEt and the organic layer was dried with MgSO4 and then filtered and concentrated. The residue was dissolved in MeOH (100 ml) and THF (100 ml), a 4 N lithium hydroxide aqueous solution (25 ml) was added, and after stirring at room temperature for 4 hours, a saturated KHSO4 aqueous solution (50 ml) was slowly added. The deposited yellow precipitate was filtered off and rinsed with AcOEt to obtain 3,5-dimethyl-6-(5-formylbenzofuran-2-yl)-4-hydroxy-2H-pyran-2-one

1. stirringAfter stirring the reaction solution at −78° C. for 30 minutes
2. stirringthe mixture was stirred at −78° C. for 4 hours
3. customto room temperature
4. extractionextraction
5. dry with materialthe organic layer was dried with MgSO4
6. filtrationfiltered
7. concentrationconcentrated
8. dissolutionThe residue was dissolved in MeOH (100 ml)
9. additionTHF (100 ml), a 4 N lithium hydroxide aqueous solution (25 ml) was added
10. stirringafter stirring at room temperature for 4 hours
11. additiona saturated KHSO4 aqueous solution (50 ml) was slowly added
12. filtrationThe deposited yellow precipitate was filtered off
13. washrinsed with AcOEt

ORD-Eintrag

ord-841bba14e3bf4be282a9ee2583a4bc9b

Quelldatensatz

uspto-grants-2003_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06589984B1