Process for producing hexahydrothieno (3,4-D)immidazole-2,4-diones

摘要

There is disclosed a process for producing hexahydrothieno[3,4-d]imidazole-2,4-diones of formula (1): ;wherein R¹ and R² are the same or different and independently represent a hydrogen atom, a lower alkyl, alkenyl, aryl or aralkyl group all of which may be substituted, which is characterized by reacting hexahydrofuro[3,4-d]imidazole-2,4-diones of formula (2): ;wherein R¹ and R² are the same as defined above, with thioamide in the presence of alkali hydrogen sulfide, sulfur and a basic compound selected from alkali metal carbonate, alkali metal sulfide, an alkali metal salt of the carboxylic acid having C2-C6 carbon atoms and an organic base having C6-C10 carbon atoms.