Weak C-H…O and C-H…N interactions in nitropyrazoles was written by Foces-Foces, C.;Jagerovic, N.;Elguero, J.. And the article was included in Acta Crystallographica, Section C: Crystal Structure Communications in 2000.Name: 1-Methyl-3-nitro-1H-pyrazole This article mentions the following:
The structures of 1-methyl-3-nitropyrazole and 1-methyl-4-nitropyrazole, C4H5N3O2, were determined The 3-nitro derivative has crystallog. m-symmetry while the 4-nitro compound has no imposed symmetry. The significant differences in bond distances and angles between the structures are ascribable to the electron-withdrawing effects of the nitro group attached to C3 or C4, resp. In both structures, the mols. are organized into layers by an extensive network of C-H…O or C-H…N H interactions. Within a layer, the mols. are arranged in a similar way, although differences of up to 0.3 Å in the analogous H…O or H…N intermol. distances are observed The cohesion of the layers is due to van der Waals and C-H…O contacts. Crystallog. data are given. In the experiment, the researchers used many compounds, for example, 1-Methyl-3-nitro-1H-pyrazole (cas: 54210-32-1Name: 1-Methyl-3-nitro-1H-pyrazole).
1-Methyl-3-nitro-1H-pyrazole (cas: 54210-32-1) belongs to pyrazole derivatives. An alternative way to synthesize multisubstituted pyrazoles is the Csingle bondH arylation of simple pyrazoles. The presence of both electronegative nitrogen atoms in the pyrazole ring reduces the electron density of the C3- and C5-positions leaving electron density of C4-position unaltered. Thus the C4-position is vulnerable to electrophilic attack. The C3 electrophilic-position may undergo deprotonation in the presence of a strong base leading to ring opening.Name: 1-Methyl-3-nitro-1H-pyrazole
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics