The crude product of the title compound was synthesized by conducting the similar reaction to that mentioned in Example 1 (1f) using 2-[5-(4-isobutylphenyl)-1,2,4-oxadiazol-3-yl]-4,5,6,7-tetrahydro-1-benzothiophen-4-ol (92 mg, 0.26 mmol) that was obtained in Example 8 (8f), carbon tetrabromide (0.10 g, 0.31 mmol), triphenylphosphine (81 mg, 0.31 mmol), ethyl 3-azetidinecarboxylate hydrochloride (65 mg, 0.39 mmol), and N,N-diisopropylethylamine (0.14 ml, 0.78 mmol). Subsequently, the crude product of the title compound thus obtained was purified by chromatography on a silica gel column using a mixed solvent of ethyl acetate and hexane (1:1 to 2:1) as the eluent to afford the title compound (44 mg) in a yield of 36% as a colourless oily product.
