Chen, Lin Zhi; Flammang, Robert; Maquestiau, Andre; Taft, Robert W.; Catalan, Javier; Cabildo, Pilar; Claramunt, Rosa M.; Elguero, Jose published an article on January 4 ,1991. The article was titled 《Thermodynamic basicity vs. kinetic basicity of diazoles (imidazoles and pyrazoles)》, and you may find the article in Journal of Organic Chemistry.Electric Literature of C7H12N2 The information in the text is summarized as follows:
The intrinsic basicity of 24 azoles (pyrazoles, indazoles, imidazoles, benzimidazoles) and 7-methylazaindole was determined by mass spectrometry techniques, ion cyclotron resonance (ICR), and/or chem. ionization (CI) in conjunction with tandem mass spectrometry (MS/MS). A reasonably good agreement (r2 = 0.967) is found between both methods (15 compounds). Thus, it is possible to use CI/MS/MS to determine the intrinsic basicity of compounds not measurable by ICR for purity or volatility reasons. Some anomalies are interpreted in terms of entropy and steric effects. The basicity data are also discussed by using empirical models (σα, σR) and chelation and annelation effects. The results came from multiple reactions, including the reaction of 1-Butyl-1H-pyrazole(cas: 52096-24-9Electric Literature of C7H12N2)
1-Butyl-1H-pyrazole(cas: 52096-24-9) belongs to pyrazoles. Pyrazoles and their related multiring analogs are common elements of a wide variety of bioactive compounds. These ring structures are rare in nature. A consequence of this is that they have previously been thought to be poor moieties to include in potential new drugs. Electric Literature of C7H12N2
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics