Novel Imidazol and Barbituric Acid Derivatives - Carbene Fragments

Derivatives of 1,3-dialkylbarbituric acid play an important role in medicinal and pharmaceutical chemistry as well as useful precursors in the preparation of new heterocyclic compounds. On the other hand, stable heterocyclic carbenes have been in the center of our interest as strong nucleophiles and as selective deprotonation reagents. Further, the resulted imidazolium compounds play an important role in the construction of ionic liquids. Various types of imidazol-2-ylidene and 1,3 dimethylbarbituric acid organic derivatives have been prepared. These new imidazol-2-ylidene derivatives were obtained by the nucleophilic substitution reactions of the imidazol-2-ylidene and 2-halo-imidazolium salts. The new derivatives of 1,3-dimethylbarbituric acid are classified into salts, ylides and neutral compounds in which the salts are produced due to the reaction with ylide-type bases, the ylide derivatives by the nucleophilic attack at the exocyclic methylene 1,3-dimethylbarbituric acid. The neutral derivatives by using 5,5-dihalo-1,3-dimethylbarbituric acid as starting material. All the prepared compounds were characterized by spectroscopic procedures and x-ray structural analysis.