Microwave Assisted Synthesis and Antimicrobial Activity Evaluation of New Heterofunctionalized Norfloxacine Derivatives

Antibacterial activity study of 1,2,4-triazole derivatives

Antibiotics are commonly used to fight against bacterial infections, but bacteria have already been resistant to almost all antibiotics due to abuse of antibiotics. 1,2,4-Triazole derived compounds possess chemotherapeutic effects including potential antibacterial activities against drug-sensitive as well as drug-resistant pathogens. Hybridization displays a high potential to develop novel drugs with the capacity to overcome drug resistance, reduce toxicity and improve pharmacokinetic profiles. More effective antibacterial candidates might be obtained by the hybridization of 1,2,4-triazole with other antibacterial pharmacophores. This review summarizes the recent advances of 1,2,4-triazole derivatives as potential antibacterial compounds, and the structure-activity relationship is also discussed.

Piperazine-azole-fluoroquinolone hybrids: Conventional and microwave irradiated synthesis, biological activity screening and molecular docking studies

A series of new 1,2,4-triazole and 1,3,4-oxadiazole derivatives was obtained via several steps sequential reactions of phenyl piperazine. Then, these compounds were converted to the corresponding fluoroquinolone hybrids via one pot three component Mannich reaction. All the reactions were examined under conventional and microwave mediated conditions, and optimum conditions were determined. The effect of different solvents and microwave power on microwave prompted reactions was investigated as well. All the newly synthesized compounds were characterized by FTIR, ¹H NMR, ¹³C NMR and EI MS spectral techniques. The antimicrobial activity, DNA gyrase and Topoisomerase IV inhibition potentials were performed. The results obtained showed that fluoroquinolone hybrids possess good antimicrobial activity. Moreover, Fluoroquinolone-azole-piperazine hybrids synthesized in the present study displayed excellent DNA gyrase inhibition. To unveil the interaction mode of compounds to receptor, a molecular docking study was performed. With an average least binding energy of -9.5 kcal/mol, all compounds were found to have remarkable inhibitory potentials against DNA gyrase (E. coli).

Synthesis and antimicrobial activity evaluation of new norfloxacine-azole hybrids

Norfloxacin-azole hybrids 3 and 6a,b were synthesized starting from norfloxacin. The treatment of these compounds with amines as a one-pot three-component reaction produced the corresponding amino derivatives 4a,b, 7a–g and 8a,b in good yields. The conventional and microwave-assisted methods were used with the latter method being more efficient. The structures of the synthesized compounds were characterized by elemental analysis, IR, 1H NMR, 13C NMR and MS. All compounds were screened for their antimicrobial activities. Most of them exhibit excellent antibacterial activity but are not active against selected fungi.