The Reaction of 1,2-Diones with Ureas-a Synthesis of 4-(1-Substituted)alkylimidazol-2-ones

The reaction between glyoxal and ureas or thioureas in formic acid in the presence of sulfinates gives 4-arylsulfonylimidazol-2-ones such as (3b) and (3e). Labile 4-arylsulfonyl-5-hydroxyimidazolidin-2-ones (2a–c) may be isolated. Acyclic or cyclic 1,2-diketones react with ureas in the presence of selected nucleophiles to give side-chain substituted imidazol-2-ones (5a–e).