To a solution of methyl 6-(6-chloro-5-hydroxy-2-phenylindol-1-ylmethyl)pyridine-2-carboxylate (100 mg) in N,N-dimethylformamide (1 mL) were added, potassium carbonate (70.4 mg) and ethyl iodide (0.031 mL) and the mixture was stirred at room temperature for 22 hours. The reaction mixture was diluted with water and extracted with ethyl acetate. The organic layer was washed successively with water and saturated saline, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluting solvent: ethyl acetate-hexane) to obtain the title compound (83.9 mg).
