Potassium carbonate (8.29 g) was added to a solution of 2-naphthalenethiol (8.01 g) and 1-bromo-6-chlorohexane (9.98 g) in N,N-dimethylformamide (65 ml). The mixture was stirred at room temperature for 3 hours. Then potassium phthalimide (9.26 g) was added to the mixture, and the resulting mixture was stirred at 100° C. for 3 hours. The reaction mixture was poured into water and extracted with ethyl acetate. The ethyl acetate layer was washed with water and dried (MgSO4), and the solvent was distilled off under reduced pressure to obtain N-[6-(2-naphthylthio)hexyl]phthalimide (18.56 g, 95.3%), which was then recrystallized from ethyl acetate-hexane. Colorless plate, mp: 109°-110° C.
