Spectroscopic and Electrochemical Properties of 1- or 2-alkyl Substituted 5- and 6-Nitroindazoles

In the framework of our general interest on the reactivity and on the pharmacological activity of heterocyclic compounds, we have examined the behaviour of some variously substituted 5- and 6-nitroindazoles. Remembering that nitroreduction processes are often essential steps for their biological activity we have collected NMR, ESR, and CV data and carried out DFT computations to gain a deep picture of electronic distribution and of reduction processes as a function of the chemical structure of the examined substrates. Interestingly, DFT computations have furnished strong support to experimental data. Moreover, the comparison between the general behaviour of 1- and 2-alkyl substituted nitroindazoles has furnished further confirmation to the known different electronic distribution in these two classes of compounds, while CV data have evidenced the ability of N1-H nitroindazoles to give rise to the formation of a dimer.