Potassium carbonate (83 mg) and 1-(3-bromopropyl)piperidine hydrobromide (54.6 mg) were added to a DMF (3 mL) solution of 4-(3-phenyl-1,4-benzoxathiin-2-yl)phenol (63.7 mg, 0.2 mmol) obtained in Reference Example 1-1, and stirred at 80° C. for 8 hours. The reaction liquid was restored to room temperature, diluted with ethyl acetate, and extracted with distilled water. The organic layer was dried with magnesium sulfate, and concentrated under reduced pressure. The obtained residue was purified by preparative thin-layer silica gel column chromatography (chloroform:methanol=9:1) to obtain the entitled compound (43.7 mg, 51%) as a yellow oil.
