General procedure for the synthesis of N-chlorophthalimide from 3-hydroxy-1H-isoindol-1-one: Anhydrous aluminum trichloride (AlCl3, 1 eq., 10 mmol, 1.36 g) was added to an anhydrous acetonitrile (CH3CN, 100 mL) solution of lead tetraacetate (Pb(OAc)4, 1 eq., 10 mmol, 4.52 g). The mixture was stirred at room temperature for 5 minutes before phthalimide (1 eq., 10 mmol, 1.5 g) was added. The resulting mixture was gently refluxed under nitrogen protection for 20 h and subsequently cooled to room temperature. The solvent was removed by rotary evaporation and the crude product was purified by column chromatography using pure dichloromethane (DCM) as eluent. Yield: 1.32 g, 71% yield.1H NMR (300 MHz, CDCl3): δ 7.94-7.91 (m, 2H), 7.82-7.79 (m, 2H) ppm.
