1-(1-(4-chlorobenzyl)-1H-indole-2-carbonyl)piperidine-4-carboxylic acid (100 mg, 0.252 mmol), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (97 mg, 0.504 mmol), and 1-Hydroxybenzotriazole (68 mg, 0.504 mmol) were dissolved in 3.0 mL of DCM. The reaction was allowed to stir for 10 minutes before N,N-Diisopropylethylamine (88 μL, 0.504 mmol) and 2-(p-tolyl)ethanamine (73 μL, 0.504 mmol) were added. The reaction was allowed to stir overnight. The reaction was diluted with water and ethyl acetate. The layers were separated and the organic layer was washed with another aliquot of water. The ethyl acetate layer was washed with saturated citric acid, saturated sodium bicarbonate, and saturated sodium chloride. The organic layer was dried over magnesium sulfate, filtered and concentrated. The crude material was purified in silica gel using the gradient 100% DCM to 5% 7M NH3 in methanol diluted with 95% DCM. After purification, pure white solid was obtained. Yield: 24 mg (White solid)
