The N-alkylation and N-arylation of unsymmetrical pyrazoles was written by Grimmett, M. Ross;Lim, K. H. Richard;Weavers, Rex T.. And the article was included in Australian Journal of Chemistry in 1979.Synthetic Route of C4H5N3O2 This article mentions the following:
Unsym. pyrazoles with alkyl, aryl, nitro and carboxyl substituents at C-3 or C-5 were methylated with Me2SO4-MeOH, Me2SO2 in basic medium, and with CH2N2. The ratios of the isomeric N-methylpyrazoles were determined by NMR and gas liquid chromatog. The modified Ullmann phenylation was also applied to these pyrazoles. Product orientations involve considerations of electronic and steric effects, the possible intermediacy of quaternary salts, and the likelihood that the dominant tautomer is reacting. In the experiment, the researchers used many compounds, for example, 1-Methyl-3-nitro-1H-pyrazole (cas: 54210-32-1Synthetic Route of C4H5N3O2).
1-Methyl-3-nitro-1H-pyrazole (cas: 54210-32-1) belongs to pyrazole derivatives. Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. Protonation of pyrazole in strong acid leads to pyrazolium cations, which undergo electrophilic substitution preferentially at C3 rather than C4. The pyrazole anion is not reactive toward nucleophiles but is mostly reactive to electrophiles.Synthetic Route of C4H5N3O2
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics