Terekhova, M. I. et al. published their research in Khimiya Geterotsiklicheskikh Soedinenii in 1979 | CAS: 15953-73-8

4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8) belongs to pyrazole derivatives. Pyrazoles, a five-membered heterocycle containing two adjacent nitrogen atoms, are the core structures found in a number of molecules that possess a wide range of pharmaceutical and agricultural activities. 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.Application In Synthesis of 4-Chloro-3,5-dimethyl-1H-pyrazole

Equilibrium nitrogen acidity of nitrogen heterocycles was written by Terekhova, M. I.;Petrov, E. S.;Rokhlina, E. M.;Kravtsov, D. N.;Shatenshtein, A. I.. And the article was included in Khimiya Geterotsiklicheskikh Soedinenii in 1979.Application In Synthesis of 4-Chloro-3,5-dimethyl-1H-pyrazole This article mentions the following:

The acid pK values of 18 heterocycles were determined in Me2SO by spectral observation of the transmetalation equilibrium with indicator CH acids. The pK values ranged from 23.3 for pyrrole to 7.8 for 2,4,5-tribromoimidazole. The pK decreased as the number of N atoms in the ring and the number of annulated benzene rings increased. LFER between pK and Σσm were found for imidazoles and pyrazoles. The pK were lower in MeOCH2CH2OMe than in Me2SO. In the experiment, the researchers used many compounds, for example, 4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8Application In Synthesis of 4-Chloro-3,5-dimethyl-1H-pyrazole).

4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8) belongs to pyrazole derivatives. Pyrazoles, a five-membered heterocycle containing two adjacent nitrogen atoms, are the core structures found in a number of molecules that possess a wide range of pharmaceutical and agricultural activities. 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.Application In Synthesis of 4-Chloro-3,5-dimethyl-1H-pyrazole

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