A rapid, highly efficient and mild green synthesis of 5,5-diphenylhydantoin derivatives was achieved from the reaction of symmetrical or unsymmetrical benzil derivatives with urea in the presence of ethanolic KOH under ultrasound irradiation. This simple method affords 5,5-diphenylhydantoin derivatives at room temperature in short reaction time with high yield and purity. This study aimed to overcome the limitations and drawbacks of the reported methods such as tedious work-up, low yield and long reaction time.

To obtain a rapid, efficient and mild synthesis of 5,5-diphenylhydantoin and 5,5-diphenyl-2-thiohydantoin derivatives, ultrasonic irradiation has been applied to the reaction mixtures containing substituted benzils and urea or thiourea derivatives catalyzed by KOH in DMSO/H(2)O, which allowed us to achieve products at room temperature in a good yield and short time without any side product. This convenient procedure will allow a further increase of the diversity within the hydantoin family.

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