Graphene Oxide-Modified Dihydropyrimidines

Abstract

This study is devoted to the synthesis of various ensembles on the basis of graphene oxide nanolayers and dihydropyrimidines and the investigation of their antimicrobial activity. The “building blocks” of ensembles, viz dihydropyrimidines were synthesized by the Biginelli reaction in the presence of low-toxic copper triflate under microwave conditions. The positive side of the reaction is the absence of any additional purification stage, formed after cooling the solution precipitate just washed with a few amount of distilled water. The structures of synthesized compounds were determined by 1H, 13C and dept135 NMR spectroscopy methods. The second component, viz graphene oxide nanolayers, was synthesized by a modified Hummer method. The modification of the method is caused by the increasing of the oxidizing agent (H2SO4+KMnO4) concentration, which allowed to receive purier nanolayers. The structure and morphology of nanolayers were investigated by SEM and XRD methods, according to which it was determined that the thickness of nanolayers is 1 nm. Subsequently, graphene oxide was modified with dihydropyrimidines. The synthesis of ensembles was performed by non-covalent coupling of dihydropyrimidines with graphene oxide nanolayers by sonication. In addition, the antimicrobial activity of ensembles against S. aureus, Ps. aeruginosa and E. coli was performed. Obtained during the analysis results were compared with the activity of pristine antibiotic ampicillin. It was found that the addition of graphene oxide nanolayers to the dihydropyrimidine molecule allowed to improve the antimicrobial activity of dihydropyrimidines