Quantitative Estimation of the Electronic Effects of Substituents in Five-membered Nitrogen-containing Aromatic Heterocycles

Data, characterising quantitatively the effect of substituents on the reactivity and physicochemical properties of five-membered nitrogen-containing heterocyclic compounds, which have accumulated in the literature during the last 15 years, are compiled in the review and discussed. The possibility of applying the Hammett and Jaffe equations in the determination of the direction of transmission of the electronic effects of substituents is analysed and the likely usefulness of this approach to the study of electronic influences by taking into account separately the inductive and resonance constants is demonstrated. The bibliography includes 215 references.