Acetic Acid → (5-Chloro-2-dimethylaminomethyl-1H-indol-4-yl)-acetic acid ethyl ester

Beteiligte Stoffe

Reaktionsschritte

5-Chloro-4-ethoxycarbonylmethyl-2-formyl-indole-1-carboxylic acid methyl ester (350 mg, 1.08 mmol) is dissolved in dry THF (10 ml) under an atmosphere of argon, and dimethylamine (290 microL of a 5.6 M solution in EtOH, 1.62 mmol) is added at RT. The reaction mixture is stirred at RT for 18 hours. A solution of sodium cyanoborohydride (82 mg, 1.29 mmol) in methanol (3 ml) and acetic acid (310 microL, 5.40 mmol) is then added. Stirring is continued for 3 hours at RT. TLC analysis indicates complete conversion of the starting material. The reaction mixture is diluted with EtOAc and poured on water. The pH is made alkaline by the addition of a saturated aqueous solution of NaHCO3. The aqueous layer is extracted with EtOAc, and the combined organic layers are washed once with concentrated aqueous NaCl solution. After drying over Na2SO4, the solvent is removed and the residue is purified by FCC (CH2Cl2/EtOH/aq. NH3 90:9:1) to give the title compound. 1H NMR (DMSO, 400 MHz) δ 1.19 (t, J=6.6 Hz, 3H), 2.20 (s, 6H), 3.55 (s, 2H), 3.97 (s, 2H), 4.11 (q, J=6.6 Hz, 2H), 6.38 (s, 1H), 7.08 (d, J=9.0 Hz, 1H), 7.26 (d, J=9.0 Hz, 1H), 11.2 (br s, 1H); ES-MS: 293.2 [M+H]−.

Herkunft & Nachweise