In 50 ml of tetrahydrofuran was dissolved 3.9 g (6.44 mmol) of dibutyl[4-[2-[4-(tert-butyldiphenylsiloxymethyl)phenyl]vinyl]-3-methoxyphenyl]amine, and 20 ml of tetrabutylammonium fluoride (1 mol solution in tetrahydrofuran) was added dropwise thereto with stirring at room temperature. The mixture was stirred for 2.5 hours. After the reaction mixture was poured into water, extraction with ethyl acetate, washing with a saturated saline solution, drying over anhydrous sodium sulfate, and concentration were performed. The residue was purified by silica gel column chromatography to give 2.28 g of a yellow liquid (yield: 96.4%).
