Reaction #554609

Reaction equation

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

lithium hydroxide trihydrate

→

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

Yield 95.0%

Solvents

tetrahydrofurane

water

THF

Conditions

Workup

1. 1
   workup.STIRRINGto stir at rt for 24 h
2. 2
   Otherwas removed under reduced pressure
3. 3
   Extractionthe product was extracted with diethyl ether (3×15 ml)
4. 4
   DryingThe organic layers were dried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Otherevaporated to dryness
7. 7
   Otherto yield a light-beige-colored solid in 95-100% yield

Procedure

Ethyl 4,6-dichloro-4-fluoro-3-(3-ethoxy-3-oxopropyl)-1H-indole-2-carboxylate (1.13 g, 3 mmol) was dissolved in 15 ml tetrahydrofurane (THF) with stirring at rt. Then a solution of 0.38 g of lithium hydroxide trihydrate (3 equiv.) in 15 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 (3×15 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. 292-294° C. 1H-NMR (DMSO-d6) δ 2.48 (m, 2H, 2′-H); 3.48 (m, 2H, 1′-H); 7.49 (dd, 1H, 2J=6 Hz, 7-H); 11.98 (s, 1H, NH); 12.72 (b, 2H, 2CO2H). 13C-NMR (DMSO-d6) δ 20.1 (C-2′); 36.1 (C-1′); 112.5 (C-7); 113.0, 113.2, 117.6, 117.7, 121.3, 121.4 (C-5); 122.3 (C-4); 127.7 (C-6); 132.5 (C-3); 147.2 (C-3a); 149.0 (C-2); 162.5 (2′-CO2H), 173.6 (2-CO2H). LC-MS (m/z): 337 [M-NH4+]+, 320 [M]+, 318 [M]−. Purity (LC-MS): 98.6%.

Source