Aluminum chloride (66 mg) was added to a solution of 6-[(4-tert-butylphenyl)(cyclopentylmethoxy)methyl]-3-chloro-2-methoxypyridine (64 mg) in cyclopentanethiol (1 mL) under ice-cooling, and then the mixture was stirred at 40° C. for two hours. Water was added to the reaction solution, followed by extraction with ethyl acetate. The organic layer was washed with water and brine, dried over anhydrous magnesium sulfate and filtered, after which the solvent was evaporated under reduced pressure. The residue was purified by preparative TLC (hexane:ethyl acetate=1:10) to give the title compound as a pale yellow solid (15 mg, 25%).
