To a solution of 2-(3-amino-5-tert-butyl-2-methoxyphenyl)-2-methylpropanenitrile (0.050 g, 0.202 mmol) in THF (0.6 mL), 2,2,2-trichloroethyl chloroformate (0.052 g, 0.245 mmol) and N,N-diisopropylethylamine (0.053 mL, 0.304 mmol) was added, and the mixture was stirred at room temperature for 2 hours. The reaction solution was evaporated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (ethyl acetate/n-hexane=0/100-30/70) to obtain 0.086 g (quantitative) of the captioned compound.
