H-1-NMR STUDY OF 3,5-DISUBSTITUTED 6-OXO-1,6-DIHYDRO-1,2,4-TRIAZINES

H-1 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 tem perature dependence of NMR spectra of three derivatives.