2-Methoxy-5-[2-(3-propyl-[1,2,4]oxadiazol-5-yl)-vinyl]-phenylamine (compound of Example 8; 0.08 g, 3.08 mmol) was dissolved in dichloromethane (10 mL) followed by addition of pyridine (0.047 mL, 0.60 mmol) and methanesulfonyl chloride (0.034 mL, 0.45 mmol) at room temperature. After stirring for 8 h, dichloromethane was evaporated and the reaction mixture was cooled to room temperature. The crude residue obtained was purified by column chromatography (silica gel, petroleum ether) to afford the title compound.
