Synthesis of uriedo and thiouriedo derivatives of peptide conjugated heterocycles – A new class of promising antimicrobials

Forty five new derivatives of ureas and thioureas were synthesized by the reaction of peptide conjugated heterocycles with isocyanates and isothiocyanates respectively. All the compounds have been characterized by IR, 1H NMR, mass and elemental analysis. The compounds were evaluated for their ability to inhibit the growth of a panel of microorganisms and all the synthesized compounds displayed an excellent antimicrobial activity. From structure–activity relationship studies, it was apparent that thioureas infact is slightly more active than ureas. Also, substituents on the phenyl ring of the title compounds play a key role in the activity. Further, compound 40 is nearly twenty times more potent than the standard used. These results present a platform for the further studies in this line.

Graphical abstractThe title compounds were synthesized and evaluated for their possibility to arrest the growth of pathogenic bacteria and fungi. All the synthesized derivatives were potentially active. Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of a series of ureas/thioureas of peptide conjugated heterocycles. ► Several candidates emerged as the most promising antimicrobial agents. ► Thioureas are active than ureas, also substituents play a key role in the biological assay.