Synthesis, antimicrobial activity and quantum chemical investigation of novel succinimide derivatives

Abstract

In the present study, twelve new 1-aryl-3-ethyl-3-methylpyrrolidine-2,5-diones were synthesized and their structures were characterized by FT-IR, 1H NMR, 13C NMR spectroscopy and elemental analysis. In the final step of synthetic rout, condensation between corresponding succinic acid and substituted anilines has been improved using the microwave irradiation. Significantly higher yields compared to conventional condensation have been observed. The preliminary biological results indicated that some of the synthesized compounds showed promising in vitro antifungal activities towards several test fungi. 1-(4-Bromophenyl)-3-ethyl-3-methylpyrrolidine-2,5-dione (8) exhibited significant in vitro inhibitory activities against broad spectra of fungus, and on the basis of obtained data, the investigated bromo derivative has to be observed as novel potential fungicide. The density functional theory (DFT) calculations have been performed in order to study the structure-activity relationship (SAR) of the investigated molecules. In order to prediction of the chemical activity of the molecule, the molecular electrostatic potential (MEP) map was analyzed for the optimized geometry of 1-phenyl-3-ethyl-3-methylpyrrolidine-2,5-dione (4) and 1-(4-bromophenyl)-3-ethyl-3-methylpyrrolidine-2,5-dione (8).