Reaktion #632025

Reaktionsgleichung

ethyl 2-(5-oxo-6,7,8,9-tetrahydro-5H-benzo[7]annulen-6-yl)acetate

potassium hydroxide

→

2-(5-oxo-6,7,8,9-tetrahydro-5H-benzo[7]annulen-6-yl)acetic acid

Lösungsmittel

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe resulting mixture was refluxed for 2 h
2. 2
   Sonstigethe EtOH was removed by evaporation
3. 3
   ExtraktionThe residue was extracted with EtOAc twice (15 mL×2)
4. 4
   SonstigeThe aqueous layer was then transferred into a flask
5. 5
   Temperaturcooled with an ice-water bath
6. 6
   workup.ADDITIONHCl was added dropwise
7. 7
   workup.ADDITIONEtOAc (60 mL) was then added
8. 8
   Sonstigethe layers were separated
9. 9
   Extraktionthe aqueous layer was extracted with EtOAc
10. 10
    WaschenThe combined extracts were washed with brine
11. 11
    TrocknenAfter being dried (MgSO4)
12. 12
    Filtrationfiltered
13. 13
    Einengenconcentrated

Vorschrift

The compound of formula (Db), ethyl 2-(5-oxo-6,7,8,9-tetrahydro-5H-benzo[7]annulen-6-yl)acetate, (6.6 g, 26.8 mmol) was dissolved in ethanol (EtOH) (30 mL), then 10% potassium hydroxide (KOH) aqueous solution (37.5 mL, 67 mmol) was added and the resulting mixture was refluxed for 2 h. After cooling to ambient temperature, the EtOH was removed by evaporation. The residue was extracted with EtOAc twice (15 mL×2). The aqueous layer was then transferred into a flask and cooled with an ice-water bath, con. HCl was added dropwise to adjust pH to about 2.0. EtOAc (60 mL) was then added, the layers were separated, and the aqueous layer was extracted with EtOAc. The combined extracts were washed with brine. After being dried (MgSO4), filtered, and concentrated, the compound of formula (Dc), 2-(5-oxo-6,7,8,9-tetrahydro-5H-benzo[7]annulen-6-yl)acetic acid, was obtained as an orange oil (5.7 g, 97%); 1H NMR (300 MHz, CDCl3) δ: 7.71-7.68 (m, 1H), 7.41-7.20 (m, 3H), 3.37-3.31 (m, 1H), 3.12-2.91 (m, 3H), 2.57-2.49 (m, 1H), 2.15-1.90 (m, 2H), 1.75-1.62 (m, 2H); LC-MS: purity: 100%; MS (m/e): 219 (MH+).

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