Reaktion #2200340

Reaktionsgleichung

Methyl (2S)-5-acetyl-2-ethyl-2,3-dihydro-benzofuran-2-carboxylate

m-chloroperbenzoic acid

NaHCO3

→

title compound

2-Ethyl-5-hydroxy-2,3-dihydro-benzofuran-2-carboxylic acid methyl ester

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturunder reflux for 2 hrs
2. 2
   WaschenThe reaction mixture was washed successively with saturated aqueous sodium sulfite (100 mL) and aqueous NaHCO3 (2×100 mL)
3. 3
   SonstigeAfter removal of solvent
4. 4
   workup.DISSOLUTIONthe residue was dissolved in methanol (100 mL)
5. 5
   workup.ADDITIONtreated with aqueous KOH (5 N, 3 mL) at 0° C. for 5 min
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated
8. 8
   SonstigeThe residue was purified by chromatography on silica gel eluting with 8:2 hexane

Vorschrift

Methyl (2S)-5-acetyl-2-ethyl-2,3-dihydro-benzofuran-2-carboxylate (3.8 g, ca. 15 mmol), m-chloroperbenzoic acid (70%, 7.7 g, 30 mmol) and NaHCO3 (3.8 g, 45 mmol) in dichloromethane (150 mL) was stirred under reflux for 2 hrs. The reaction mixture was washed successively with saturated aqueous sodium sulfite (100 mL) and aqueous NaHCO3 (2×100 mL). After removal of solvent, the residue was dissolved in methanol (100 mL) and treated with aqueous KOH (5 N, 3 mL) at 0° C. for 5 min. The reaction was neutralized with excess solid sodium bicarbonate, filtered and concentrated. The residue was purified by chromatography on silica gel eluting with 8:2 hexane:ethyl acetate to give the title compound.

Quelle