Reaktion #1930422

Reaktionsgleichung

NaH

121a

Ethyl 4,5,6,7-Tetrahydro-1H-indole-2-carboxylate

2-bromo-1,1-diethoxyethane

→

121b

Ausbeute 51.0%

Ethyl 1-(2,2-Diethoxyethyl)-4,5,6,7-tetrahydro-1H-indole-2-carboxylate

Ausbeute 51.0%

Lösungsmittel

N,N-dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction was heated at 70° C. for 30 h
2. 2
   Sonstigequenched with water (100 mL)
3. 3
   ExtraktionThe mixture was then extracted with ethyl acetate (3×100 mL)
4. 4
   EinengenThe combined organic phase was concentrated under reduced pressure
5. 5
   Sonstigethe residue was purified with silica-gel column chromatography
6. 6
   Wascheneluting with 40:1 petroleum ether/ethyl acetate

Vorschrift

To a suspension of NaH (1.44 g, 60.2 mmol) in N,N-dimethylformamide (DMF)(30 mL) was slowly added 121a (5.80 g, 30.1 mmol) at 0° C. The resulting mixture was stirred at room temperature for 0.5 h, followed by the addition of 2-bromo-1,1-diethoxyethane (11.9 g, 60.2 mmol). The reaction was heated at 70° C. for 30 h and quenched with water (100 mL). The mixture was then extracted with ethyl acetate (3×100 mL). The combined organic phase was concentrated under reduced pressure and the residue was purified with silica-gel column chromatography eluting with 40:1 petroleum ether/ethyl acetate to afford 121b (4.7 g, 51%). MS-ESI: [M-ethanol+H]+ 264. 1H NMR (500 MHz, DMSO-d6) δ 6.65 (s, 1H), 4.59 (t, J=5.0 Hz, 1H), 4.17-4.16 (m, 4H), 3.59-3.57 (m, 2H), 3.27-3.26 (m, 2H), 2.61 (t, J=6.0 Hz, 2H), 2.51 (t, J=6.0 Hz, 2H), 1.73-1.71 (m, 2H), 1.63-1.61 (m, 2H), 1.25 (t, J=7.0 Hz, 3H), 1.02 (t, J=7.0 Hz, 6H).

Quelle