N-Linked azole as a substituent

12 Substituents Attached to Ring Nitrogen Atoms 3.4.3.12.1 N-Linked azole as a substituent 

It is instructive to consider iV-substituted azoles in reverse, i.e. the azole ring as the substituent linked to some other group. Hammett and Taft cr-constant values for azoles as substituents are given in Table 12. The values show that all A -azolyl groups are rather weak net resonance donors, imidazolyl-1 being the strongest. They are all rather strong inductive acceptors, with pyrazole considerably weaker in this respect than imidazole or the triazoles. 

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