A small screw cap test tube was charged with 2-Ethyl-5-methyl-2H-pyrazole-3-carboxylic acid [4-(3-hydroxymethylene-2-oxo-2,3-dihydro-1H-indol-5-ylmethyl)-phenyl]-amide (prepared below, 70 mg, 0.175 mmol) and THF (1 mL). To the resulting solution was added 4-(4-Methyl-piperazin-1-yl)-phenylamine (66.8 mg, 0.349 mmol), and the mixture was stirred for 24 h at 65° C. Subsequently, the reaction mixture was cooled to room temperature and then diluted with EtOAc (2 mL). The solution was washed with water (2 mL) and the water layer was re-washed with additional EtOAc (2 mL). The combined organic layers were then concentrated in vacuo affording the crude product. The crude product was further purified by silica gel column chromatography with 5% methanol in chloroform as eluant to give the desired product as a solid in 55% yield (55 mg, 0.96 mmol).
