Collect. Czech. Chem. Commun. 1995, 60, 251-256

1H NMR Study of 3,5-Disubstituted 6-Oxo-1,6-dihydro-1,2,4-triazines

Karel Nálepaa, Aleš Halamab, Taťjana Nevěčnáa and Vojtěch Bekáreka

a Department of Analytical Chemistry, Palacký University, 771 46 Olomouc, Czech Republic
b Department of Organic Chemistry, University of Pardubice, 532 10 Pardubice, Czech Republic


1H NMR spectra have been measured of seven 3,5-disubstituted 6-oxo-1,6-dihydro-1,2,4-triazines, and tautomerism of these compounds has been evaluated in connection with the nature of substituents, medium, and temperature. The title compounds exist in their benzyl or benzylidene forms or as a mixture of both forms. Thermodynamic characteristics of the transition between the two forms have been determined from the temperature dependence of NMR spectra of three derivatives.