1H and 13C NMR spectra of condensed benzimidazole and imidazobenzodiazepines

Benzimidazoles are heterocyclic compounds that have awakened great interest during the last few years because of their proven biological activity as antiviral, antimicrobial, and antitumoral agents. For this reason, the development of a systematic NMR study of condensed benzimidazole compounds constitutes a significant tool in understanding the molecular dynamics and the structural parameters that govern their behavior. The 1H and 13C NMR spectra of new imidazobenzodiazepines were investigated. Based on the study of NMR chemical shifts, we discuss the environmental effect of the nucleus 13C. The correlation 1H–13C proved to be a useful method for distinguishing the assignment of carbon.