Luijten, W. C. M. M. et al. published their research in Organic Mass Spectrometry in 1979 | CAS: 5334-39-4

3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4) belongs to pyrazole derivatives. The 1H-pyrazole provides an excellent means by which to provide the requisite hydrogen bond acceptor–donor motifs, whether as a monocyclic ring or as a fused indazole ring. Pyrazole rings have been used as core components of several leading non-steroidal anti-inflammatory drugs (NSAIDs) and antihypertensive drugs. It has also been found to be useful as a bifunctional ligand for metal catalysis.COA of Formula: C4H5N3O2

Mass spectrometry of nitroazoles. I. The mass spectra of methyl substituted nitropyrazoles was written by Luijten, W. C. M. M.;Van Thuijl, J.. And the article was included in Organic Mass Spectrometry in 1979.COA of Formula: C4H5N3O2 This article mentions the following:

The mass spectra of all isomers of methylnitropyrazoles are reported. Generally, the spectra are characteristic of nitropyrazoles. In some cases however, ortho effects occur, which were recognizable by the primary loss of •OH, H2O, •CHO and HCHO. In the experiment, the researchers used many compounds, for example, 3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4COA of Formula: C4H5N3O2).

3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4) belongs to pyrazole derivatives. The 1H-pyrazole provides an excellent means by which to provide the requisite hydrogen bond acceptor–donor motifs, whether as a monocyclic ring or as a fused indazole ring. Pyrazole rings have been used as core components of several leading non-steroidal anti-inflammatory drugs (NSAIDs) and antihypertensive drugs. It has also been found to be useful as a bifunctional ligand for metal catalysis.COA of Formula: C4H5N3O2

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics