Theoretical study of the effect of the solvent on the electronic properties of pyrimidopyrimidine derivatives

Quantum calculations were carried out on some pyrimidopyrimidine tautomeric heterocyclic derivatives both in gas phase and in solution in order to study the influence of the migration of hydrogen on their electronic and structural properties as well to highlight the effect of the solvent on the process of tautomerism. Results indicate that the electronic properties of the studied heterocycles are influenced by the nature of the solvent used. All tautomeric forms are more stable in H2O and DMSO than in CHCl3 and in the gas phase. The predominance of the di-ketone form in gas phase and solution is observed.