22244-54-8Relevant articles and documents
METHYLATION OF 3-NITRO-1,2,4-TRIAZOL-5-ONE
Kofman, T. P.,Pevzner, M. S.,Zhukova, L. N.,Kravchenko, T. A.,Frolova, G. M.
, p. 375 - 378 (2007/10/02)
The methylation of 3-nitro-1,2,4-triazol-5-one with dimethyl sulfate in an alkaline medium is unselective at both substitution steps and occurs at the N1 and N4 atoms of the ring and the oxygen of the oxo group.The degree of conversion (mono- or disubstitution) and the isomeric composition of the alkylation products depend on the reactivity of the nucleophilic centers and on the reaction conditions (the ratio of the reagents, the pH of the medium, and the solvent).The UV spectra were investigated and the pKa values were determined for 3-nitro-1,2,4-triazol-5-one and its monomethyl derivatives.The first step in the dissociation of 3-nitro-1,2,4-triazol-5-one is removal of the proton from the N4 atom, and this determines the preferential methylation at this center in the monoanion.In the dianion susbtitution at the more nuclephilic heteratom N1 predominates.