1,2,4-Triazines. IV. The Structural Elucidation of Some New N-Methyl 3-Amino-1,2,4-Triazin-5(2H)-ones by Carbon-13 Nuclear Magnetic Resonance Spectroscopy

Methylation of 3-amino-1,2,4-triazin-5(2H)-one yields a mixture of the zwitterion 3-amino-1-methyl-1,2,4-triazinium-5-olate and 3-amino-2- methyl-1,2,4-triazin-5(2H)-one. With appropriate substituents located at position C6 and on the exocyclic amino group at C3, methylation was directed to the N1 or N2 positions exclusively. All methylation isomers were identified by carbon-13 nuclear magnetic resonance spectroscopy by reference to long-range coupling patterns.