Synthesis
1. Saccharin (6.0 g) was dissolved in methanol (120 mL), stirred at room temperature, tert-butyl hypochlorite (5 mL) was added slowly, and the reaction was carried out for 5 min to obtain N-chlorophthaloylbenzimide intermediate 1a (6.0 g, 84% yield).
2. Intermediate 1a (3.0 g) was mixed with silver trifluoromethylsulfide (3.6 g) in acetonitrile (40 mL), and the reaction was stirred at room temperature for 10 min to obtain the target product N-chlorophthaloylbenzimide 1 (3.3 g, 86% yield).
Note: The product 1 is a white solid at room temperature, easily soluble in organic solvents such as dichloromethane, chloroform, acetone and acetonitrile.
References
[1] Synlett, 2006, # 2, p. 194 - 200
[2] Angewandte Chemie, International Edition, 2014, vol. 53, # 35, p. 9316 - 9320,5
[3] Angewandte Chemie, 2014, vol. 126, # 35, p. 9470 - 9474,5
[4] Patent: CN104945294, 2016, B. Location in patent: Paragraph 0135; 0136; 0137; 0138
[5] Patent: CN104945298, 2016, B. Location in patent: Paragraph 0187; 0188; 0189; 0190
