Trifluoroacetic acid → HCID 67235539, compound

Participants

Reaction Steps

To a mixture of diethyl 1-{3-[(tert-butoxycarbonyl)amino-]-2,2-dimethylpropyl}-1H-indole-2,6-dicarboxylate and diethyl 1H-indole-2,6-dicarboxylate (Intermediate A, 21.9 g, 49 mmol) in CH2Cl2 (400 mL) is added TFA (100 mL). The mixture is stirred at room temperature for 2 h and then all the solvent is evaporated. The residue is dissolved in EtOAc (300 mL) and is washed with saturated NaHCO3 solution until the pH is about 7. The aqueous layer is extracted with EtOAc (100 mL) and the organic layers are combined, dried (Na2SO4) and concentrated. To a solution of the residue in ethanol (1000 mL) are added triethylamine (20.5 mL, 147 mmol) and K2CO3 (20.3 g, 147 mmol). The mixture is heated at 80° C. for 2 h and then cooled to room temperature and stirred for 16 h. The solid formed the reaction mixture is filtered off and set aside. The filtrate is concentrated and the residue is purified by flash column chromatography using methanol in CH2Cl2 to afford the title compound (7.6 g, 66% for 3 steps).

Provenance & Evidence