Synthesis of Some Novel Pyrimidinedione and Pyrimidinetrione Derivatives by a Greener Method: Study of Their Antimicrobial Activity and Photophysical Properties

Abstract

A series of novel pyrimidinedione- and pyrimidinetriones-based compounds were synthesized by different techniques such as with conventional Knoevenagel condensation alone, with a Rhizopus oryzae lipase biocatalyst, and with a deep eutectic solvent (DES). The yield was found to be maximum by using lipase and DES. Reuse of the lipase and DES was possible up to four consecutive cycles. These methods are mild, highly efficient, and amenable to scaleup. The products were found to exhibit appreciable in vitro antibacterial activity against Echerichia coli, Pseudomonas neumoniae, and Micrococcus and in vitro antifungal activity against Aspergillus niger and Candida albicans. All the compounds exhibited appreciable in vitro activity against the tested strains. The photophysical properties and thermal stability of the products were also investigated.

GRAPHICAL ABSTRACT

Keywords:

• Antimicrobial activity
• DES
• green chemical methods
• Knoevenagel condensation
• lipase

Notes

^a By using conventional catalyst, reactions were carried out at reflux temperature.

^b By using lipase as a biocatalyst, reactions were carried out at 40–45 °C.

^c By using deep eutectic solvent, reactions were carried out at 40–45 °C.

All compounds were confirmed by FTIR, ¹NMR, ¹³C NMR, mass analysis.

d = Isolated Yield.

MIC: Minimal inhibitory concentration values.

Standard: bacterial strain: streptomycin 125 µg/mL, fungal strains: fluconazole 125 µg/mL.

Solvent used: DMSO (Dimethylsulphoxide).

^a Bacterial strain: E. coli NCIMB 8110, Micrococcus, Pseudomonas neumoniae.

^b Fungal Strain: Candida albicans; Aspergillus niger.