Pseudothiohydantoin

105-39-5

17356-08-0

556-90-1

A) Synthesis of 2-imino-4-thiazolidinone (IV): 20g (0.263mol) of thiourea (III) and 50ml of ethanol were added to a 100ml round bottom flask fitted with a condenser. The mixture was heated to reflux. Over a period of 30 min, 32.22 g (0.263 mol) of ethyl chloroacetate (II) was slowly added dropwise to the reaction system. The reflux state was maintained and the progress of the reaction was monitored by thin layer chromatography (TLC). After completion of the reaction, the mixture was cooled to room temperature. The 2-imino-thiazolidin-4-one hydrochloride (pseudothioglycolide hydrochloride) was isolated by filtration. The hydrochloride was dissolved in water, neutralized with sodium acetate solution and 2-imino-4-thiazolidinone (IV) was precipitated after cooling. The product was collected by filtration and dried at 60 °C. Yield: 86%; melting point: 254-259 °C.