After adding 3.3 ml of TBAF (1.0 M, THF solution) to a 15 ml THF solution containing 1.8 g of {2-(3-methoxy-5-triisopropylsilanyloxyphenyl)-2-[4-(5-methyl-[1,2,4]oxadiazol-3-yl)phenylimino]-1-methylsulfanylethylidene}carbamic acid methyl ester, the mixture was stirred at 0° C. for 1 hour and 30 minutes. Saturated aqueous ammonium chloride was added to the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with water and saturated brine and dried over anhydrous magnesium sulfate. The desiccating agent was filtered off and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate-heptane) to give the title compound (1.06 g) as a yellow solid.
