MNDO,AM1 and PM3 calculations in the study of the energy and structure of quinazolone tautomers

MNDO, AM1, and PM3 calculations were used to study the tautomeric forms of quinazolones. The relative energy of the tautomers closest to the experimental value was obtained using the AM1 and PM3 methods. The keto-enol tautomeric equilibrium of quinazolones in the gas phase is shifted toward the ketone form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1246–1251, September, 1993.