Into a dry reaction vessel, methyl 2-[1-[4-(2-naphthamido)benzyl]-2-methyl-1H-indol-3-yl]acetate (150 mg, 0.324 mmol), lithium hydroxide monohydrate (55 mg, 1.31 mmol), 3 mL tetrahydrofuran, 3 mL water were weighed, and stirred at room temperature for 2 h. The reaction was monitored to be complete by TLC. The solvent was rotate evaporated. It was adjusted to pH=3-4 with 2 N HCl solution. It was extracted by ethyl ester, rotate evaporated to dryness to obtain the product as a white solid 80 mg. After recrystallization by ethyl acetate, a pure product 51 mg was obtained, at a yield of 35.2%.
