imidazolone imidazolone imidazolones are a family of heterocyclic compounds, the parents of which have the formula oc(nh)2(ch)2. two isomers are possible, depending on the location of the carbonyl (co) group. the nh groups are nonadjacent. a common route to imidazol-2-ones involves condensation of ureas and acyloins. some are of interest in the pharmaceuticals. 4-imidazolones arise from the condensation of amidines with 1,2-dicarbonyls such as glyoxal. 4-imidazolones are advanced glycation endproducts (ages), a class of modified proteins that are biomarkers for diabetes. in this drawing the imidazolone is the c3n2 ring in red and black.