Microwave-assisted Synthesis of Novel Pyrazole Derivatives and their Biological Evaluation as Anti-Bacterial Agents

Comb Chem High Throughput Screen. 2021;24(5):695-700. doi: 10.2174/1386207323666201019152206.

Abstract

Aims and objectives: Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol.

Materials and methods: The structural features of the synthesized compounds were characterized by melting point, FT-IR, 1H, 13C NMR and elemental analysis.

Results: The antibacterial activities of the synthesized pyrazoles were evaluated against three gram-positive bacteria, such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium.

Conclusion: All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain, and none of them demonstrated antibacterial activity against E. coli.

Keywords: 13C NMR; 1H NMR; FT-IR; Pyrazole; antibacterial; chalcone; microwave assisted.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Bacillus subtilis / drug effects
  • Enterococcus / drug effects
  • Escherichia coli / drug effects
  • Microbial Sensitivity Tests
  • Microwaves*
  • Pyrazoles / chemical synthesis
  • Pyrazoles / chemistry
  • Pyrazoles / pharmacology*
  • Salmonella typhimurium / drug effects
  • Staphylococcus aureus / drug effects

Substances

  • Anti-Bacterial Agents
  • Pyrazoles
  • pyrazole

Supplementary concepts

  • Enterococcus durans