Paper Title
Effect of Reaction Conditions on the Synthesis of Mesoionic Betaines Containing a Pyrimidine Moiety

The aim of this study was to investigate the influence of some parameters on the synthesis reaction of bicyclic and monocyclic betaines containing a pyrimidine moiety; obtained by condensation of 2-aminopyridine or N, N’-disubstituted amidines with substituted malonic esters, yielding mesoionic structures. We examined the influences of the amount of malonic ester, the nature of solvent and the reaction time on the final yield of condensation process. The experiment results showed that when the reaction mixtures of 2-aminopyridine or N, N’-disubstituted amidines with various amounts of malonic ester were heated, yield of bicyclic betaine was found to be independent on the reaction time, while the reaction conditions greatly affected the monocyclic betaines synthesis. It was found that yield increases with the increase in reaction time and concentration of malonic ester. We noticed that when 2-aminopyridine or N, N’-disubstituted amidines were stirred with a malonic ester highly reactive, the reaction took place under milder conditions in few minutes and the nature of solvent had a significant effect on the yield of monocyclic betaines, while it had no effect on the yield of bicyclic betaines. The results also showed that a longer reaction time is unfavorable factor, whereas a time of 30-60 min leads to a better yield of these compounds. Keywords - Betaines, Mesoionic compounds, Pyrimidine, Reaction Conditions, Synthesis