Electron density distribution in-heterocyclic systems with two adjacent nitrogen atoms. V. Dipole moments of some halo, amino, and hydroxy derivatives of pyrazole was written by Hillers, S.;Mazeika, I.;Grandberg, I. I.;Gorbacheva, L. I.. And the article was included in Khimiya Geterotsiklicheskikh Soedinenii in 1967.SDS of cas: 15953-73-8 This article mentions the following:
Dipole moments, μ, of 19 pyrazole (I) derivatives have been measured in C6H6 or dioxane at 25° and compared with those calculated The calculations were based on the geometrical structure of I determined by means of x-rays and the values of dipole moments of substituents were taken from the literature. The values found were (the substituents in I, solvent, μdetd. (D.), μcalcd. (D.) given): 1-phenyl-3-amino, C6H6, 1.85, 1.44; 1-phenyl-4-amino, C6H6, 2.36, 2.68; 1-phenyl-5-amino, C6H6, 3.34, 3.41; 1-phenyl-3-chloro, C6H6, 3.76, 3.49; 1-phenyl-4-chloro, C6H6, 2.28, 2.38; 1-phenyl-5-chloro, C6H6, 1.25, 0.51; 1-phenyl-4-bromo, C6H6, 2.28, 2.36; 1-phenyl-5-bromo, C6H6, 1.33, 0.48; 3,5-diphenyl-4-bromo, C6H6, 2.62, 2.49; 3,5-dimethyl-4-chloro, C6H6, 2.43, 2.51; 3,5-dimethyl-4-iodo, C6H6, 2.19, 2.21; 3,4-dibromo, C6H6, 4.66, 3.96; 3,4,5-tribromo, C6H6, 2.48, 3.05; 3,5-dimethyl-4-nitro, C6H6, 3.88, 3.54; 1-phenyl-3-hydroxy, dioxane, 2.18, -; 1-phenyl-4-hydroxy, dioxane, 2.43, -; 1-phenyl-5-hydroxy, dioxane, 3.41, -; 1-p-aminophenyl, C6H6, 2.97, 3.00; 1-p-hydroxyphenyl, dioxane, 2.71, 2.72. The difference between μdetd. and μcalcd. represents the interaction of substituents with the I nucleus, thus indicating the degree of the polarization of I nucleus as the function of the nature and position of substituents. Also, it was shown that I has an unsym. structure with a H atom bound to one N atom only. Since there are 2 possible tautomeric structures of 3,4-dibromopyrazole, it follows from the comparison of exptl. and calculated μ’s that it has the structure II. In the experiment, the researchers used many compounds, for example, 4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8SDS of cas: 15953-73-8).
4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8) belongs to pyrazole derivatives. As is the case with imidazoles, the pyrazole ring offers many opportunities to create new multiring systems that incorporate this heterocycle. Pyrazoles are commonly used scaffold molecules in drug discovery projects. The use of pyrazole derivatives is based on their analgesic, anti-inflammatory, antipyretic, antiarrhythmic, sedative, muscle relaxant, neuroleptic, anticonvulsant, monoamine oxidase inhibitory, antidiabetic and antibacterial activities.SDS of cas: 15953-73-8
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics