A series of new heterocycle hybrids incorporating pyrazole
and
isoxazoline rings was successfully synthesized, characterized, and
evaluated for their antimicrobial responses. The synthesized compounds
were obtained utilizing N-alkylation and 1,3-dipolar
cycloaddition reactions, as well as their structures were established
through spectroscopic methods and confirmed by mass spectrometry.
To get more light on the regioselective synthesis of new hybrid compounds,
mechanistic studies were performed using DFT calculations with B3LYP/6-31G(d,p)
basis set. Additionally, the results of the preliminary screening
indicate that some of the examined hybrids showed potent antimicrobial
activity, compared to standard drugs. The results confirm that the
antimicrobial activity is strongly dependent on the nature of the
substituents linked pyrazole and isoxazoline rings. Furthermore, molecular
docking studies were conducted to highlight the interaction modes
between the investigated hybrid compounds and the Escherichia
coli and Candida albicans receptors.
Notably, the results demonstrate that the investigated compounds have
strong protein binding affinities. The stability of the formed complexes
by the binding between the hybrid compound 6c, and the
target proteins was also confirmed using a 100 ns molecular dynamics
simulation. Finally, the prediction of ADMET properties suggests that
almost all hybrid compounds possess good pharmacokinetic profiles
and no signs of observed toxicity, except for compounds 6e, 6f, and 6g.