Reaktion #554605

Reaktionsgleichung

lithium hydroxide trihydrate

ethanol

ethyl acetate

Ethyl 4,6-dibromo-3-(3-ethoxy-3-oxopropyl)-1H-indole-2-carboxylate

→

3-(2-Carboxyethyl)-4,6-dibromo-1H-indole-2-carboxylic acid

Ausbeute 95.0%

Lösungsmittel

hexane

THF

water

methanol

—

petrol ether

water

tetrahydrofurane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGto stir at rt for 24 h
2. 2
   Sonstigewas removed under reduced pressure
3. 3
   Extraktionthe product was extracted with diethyl ether (3×30 ml)
4. 4
   TrocknenThe organic layers were dried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Sonstigeevaporated to dryness
7. 7
   Sonstigeto yield a light-beige-colored solid in 95-100% yield

Vorschrift

Ethyl 4,6-dibromo-3-(3-ethoxy-3-oxopropyl)-1H-indole-2-carboxylate (4.47 g, 10 mmol) was dissolved in 25 ml tetrahydrofurane (THF) with stirring at rt. Then a solution of 1.26 g of lithium hydroxide trihydrate (3 equiv.) in 25 ml water was added and the resulting mixture was let to stir at rt for 24 h. After completion of the reaction THF was removed under reduced pressure and the pH was adjusted to 4-5, and the product was extracted with diethyl ether (3×30 ml). The organic layers were dried over magnesium sulfate, filtered, and evaporated to dryness to yield a light-beige-colored solid in 95-100% yield. mp. 259° C.; well soluble in methanol, ethanol and ethyl acetate; slightly soluble in petrol ether, water, hexane. 1H-NMR (MeOH-d4): δ 2.67 (t, 2H, 3J=8.4 Hz, CH2); 3.71 (t, 2H, 3J=8.4 Hz, CH2); 7.42 (d, 1H, 4J=1.6 Hz, C7-H); 7.62 (d, 1H, 4J=1.6 Hz, C5-H). 13C-NMR (MeOH-d4): δ 21.4 (C-2′); 37.9 (C-1′); 115.9 (C-7); 117.0 (C-4); 118.8 (C-6); 123.9 (C-3); 125.5 (C-2); 127.9 (C-3a); 128.2 (C-5); 139.6 (C-7a); 164.6 (2′-CO2H); 170.1 (2-CO2H). LC-MS (m/z): 392.0 [M]+; 390.0 [M]−. Purity (LC-MS): 99%.

Quelle