50.0 g (130 mmols) of N-ethyl-N-[6-(tetrahydropyran-2-yl)oxyhexyl]-4-bromoaniline was dissolved in 180 ml of anhydrous tetrahydrofuran in an atmosphere of argon, and the solution obtained was cooled to -78° C. To the reaction solution obtained, 174.4 ml (2.2-fold equivalent weight) of t-butyl lithium (1.64 M, n-pentane solution) was dropwise added, followed by stirring for 1 hour. To the mixture obtained, 12.3 g (1.3-fold equivalent weight) of N,N-dimethylformamide was dropwise added, which was then stirred at room temperature for 2 hours and 30 minutes. The resultant reaction solution was concentrated, and dissolved in 500 ml of ethyl acetate, followed by washing twice with 300 ml of water. The organic layer thus formed was dried with anhydrous sodium sulfate, followed by concentration under reduced pressure. The residue thus obtained was purified by silica gel column chromatography (developing system: hexane/ethyl acetate=4/1) to obtain 34.7 g of N-ethyl-N-[6-(tetrahydropyran-2-yl)oxyhexyl]-4-formylaniline (yield: 80%; a pale-yellow oily liquid). 1H-NMR Spectrum [δ(ppm)]: 1.20(t, 3H, J=7.0 Hz), 1.35-1.95(m, 14H), 3.20-3.55(m, 6H), 3.73(m, 1H), 3.86(m, 1H), 4.57(t, 1H, J=3.6 Hz), 6.65(d, 2H, J=9.7 Hz), 7.71(d, 2H, J=9.7 Hz), 9.69(s, 1H).
