A solution of 3-quinolin-6-ylpropanal in acetonitrile was cooled to 0° C before L-proline, benzoic acid, and N-chlorosuccinimide were added at 0° C. The reaction mixture was stirred at 0° C for 3 h, and the resulting clear solution was allowed to warm to room temperature and stirred at RT for 18 h. The reaction mixture became a thick suspension, and LCMS showed the completion of the reaction. Ethyl acetate (EtOAc) was added to the reaction mixture, stirring at room temperature for 1 h. The solids were collected by filtration, washed with ethyl acetate, and dried under vacuum at 40-45° C to constant weight to afford 1-[2-Chloro-1-hydroxy-3-(6-quinolinyl)propyl]-2,5-pyrrolidinedione as an off-white powder. yield: 65.