Novel phenylazo derivatives of condensed and uncondensed thiophene. Synthesis, characterization, and antimicrobial studies

Abstract

In the search for new therapeutic agents against microbial infections, two novel series of monocyclic and tricyclic 5-(phenylazo)thiophene systems were synthesized based on 3-amino-2-thioxopyrimidinone and 2-cyanoacetamidothiophene derivatives 4 and 6. Functionalization of the pyrimidine ring in precursor 4 resulted in the formation of the target tricyclic condensed thiophenes 7, 12, and 13a, b, by the application of a variety of addition, substitution, and condensation reactions. On the other hand, derivatization of the versatile cyanoacetylated compound 6 led to a second series of monocyclic N-substituted aminothiophenes 15, 17, 19, and 20, through convenient methods. The new thiophene-based derivatives were tested for their antimicrobial activity with reference to relevant standard drugs. They displayed different levels of antibacterial activity, with compound 7 showing essentially the highest antipseudomonal activity. As for antifungal action, the compounds under investigation, unfortunately, had no inhibitory effects against test fungi isolates except for 7 and 20, that revealed slight inhibition. © 2011 Verlag der Zeitschrift für Naturforschung.