Reaktion #322260

Reaktionsgleichung

water

6,7-dimethoxy-1-tetralone

NaBH4

→

title product

Ausbeute 94.0%

1.2-Dihydro-6.7-dimethoxynaphthalene

Ausbeute 94.0%

Lösungsmittel

methylene chloride

toluene

ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeMost of the solvent was removed by evaporation
2. 2
   workup.ADDITIONto the residue was added 150 mL of methylene chloride and 50 mL of water
3. 3
   SonstigeThe aqueous layer was separated
4. 4
   Waschenwashed with brine
5. 5
   Trocknendried over MgSO4
6. 6
   Einengenconcentrated
7. 7
   Sonstigeto leave an orange oily residue
8. 8
   Temperaturthe solution was heated
9. 9
   Temperaturat reflux for 30 min
10. 10
    TemperaturThe reaction was cooled to room temperature
11. 11
    ExtraktionThe aqueous layer was extracted with ethyl acetate
12. 12
    Waschenwashed with brine
13. 13
    Trocknendried over MgSO4
14. 14
    Einengenconcentrated
15. 15
    Sonstigeto leave an orange oil
16. 16
    Waschenwhich was washed with saturated sodium bicarbonate solution, water
17. 17
    Sonstigedried
18. 18
    Einengenconcentrated

Vorschrift

To a solution of 5.01 g (24.3 mmol) of 6,7-dimethoxy-1-tetralone (Aldrich Chemical Co.) in 100 mL of ethanol was added 0.932 g (24.6 mmol) of NaBH4, and the mixture was stirred for 14 hours at room temperature. Most of the solvent was removed by evaporation, and to the residue was added 150 mL of methylene chloride and 50 mL of water. The aqueous layer was separated and reextracted with methylene chloride, then the organic extracts were combined and washed with brine, dried over MgSO4, and concentrated to leave an orange oily residue. The crude intermediate product was dissolved in 100 mL of refluxing toluene, to which was added 48 mg of p-toluenesulfonic acid, and the solution was heated at reflux for 30 min. The reaction was cooled to room temperature and 50 mL of water was added. The aqueous layer was extracted with ethyl acetate, and the organic extracts were combined, washed with brine, dried over MgSO4, and concentrated to leave an orange oil. This was dissolved in methylene chloride, which was washed with saturated sodium bicarbonate solution, water, dried and concentrated to afford 4.34 g of the title product (94% yield). NMR (CDCl3) δ:6.67 (s, 1H), 6.60 (s, 1H), 6.38 (d, 1H, J=10 Hz), 5.94(dt, 1H, J=4 Hz, J=10 Hz), 3.88 (s, 3H), 3.86 (s, 3H), 2.73 (t, 2H, J=8 Hz), 2.32-2.24 (m, 2H).

Quelle