102359-00-2

65435-04-3

102359-00-2

The general procedure for the synthesis of 2-oxoindoline-5-carboxylic acid from 5-chloroacetylindone was as follows (Example 13, from Table 3): 6.7 g of 2-hydroxyindole acid was slowly added to a stirred suspension of 30 mL of dichloroethane containing 23 g of aluminum chloride under ice bath conditions. Subsequently, 11.3 g of chloroacetyl chloride was slowly added dropwise, during which hydrogen chloride gas was released. The reaction mixture was stirred for 10 minutes and then gradually warmed to 40-50°C and maintained at this temperature for 1.5 hours. The progress of the reaction was monitored by thin layer chromatography (unfolding agent: ethyl acetate, stationary phase: silica gel) to confirm complete consumption of the raw materials. Upon completion of the reaction, the mixture was cooled to room temperature and carefully poured into ice water. The resulting precipitate was collected by vacuum filtration, washed with water and dried under vacuum to give 10.3 g (98% yield) of 5-chloroacetyl-2-hydroxyindole as an off-white solid.