Method for synthesizing 1-isopropyl benzamide-3-(3,5-dichlorophenyl)hydantoin

The invention discloses a method for synthesizing 1-isopropyl benzamide-3-(3,5-dichlorophenyl)hydantoin. The method comprises the following steps: reacting by virtue of chloroacetyl chloride and urea in the presence of a catalyst, so as to prepare hydantoin; reacting by virtue of hydantoin and 1,3,5-trichlorobenzene in the presence of triethylamine, so as to prepare 3,5-dichlorophenyl-hydantoin; and reacting by virtue of 3,5-dichlorophenyl-hydantoin and isopropyl isocyanate in the presence of a catalyst, so as to prepare 1-isopropyl benzamide-3-(3,5-dichlorophenyl)hydantoin. According to a reaction route utilized in the method, an expensive raw material 3,5-dichloroaniline and a highly toxic raw material phosgene are not adopted, and the method has the characteristics of few reaction steps, less waste gas, wastewater and industrial residue, high product yield and good product quality as well as obvious economic and social benefits.