A Versatile Approach for the Synthesis, Characterization, and Bioassay of Novel 3-(1-Acetyl-5-substituted phenyl-4, 5-dihydro-1H-pyrazol-3-yl)-4-hydroxy-1-methyl/phenylquinolin-2(1H)-one Derivatives

A series of novel 3-(1-acetyl-5-substitutedphenyl-1H-pyrazol-3-yl)-4-hydroxy-1-methylquinolin-2(1H)-ones (Va-Vf) and 3-(1-acetyl-5-substitutedphenyl-1H-pyrazol-3-yl)-4-hydroxy-1-phenylquinolin-2(1H)-ones (Vg-Vl) were designed and synthesized by the condensation of hydrazine hydrate with (E)-3-(3-(substituted phenyl)acryloyl)-4-hydroxy-1-methyllquinolin-2(1H)-one (IVa-IVf) and (E)-3-(3-(substituted phenyl)acryloyl)-4-hydroxy-1-phenylquinolin-2(1H)-one (IVg-IVl) and these intermediates are prepared from 3-acetyl-4-hydroxy-1-methylquinolin-2(1H)-one (Ia) and 3-acetyl-4-hydroxy-1-phenylquinolin-2(1H)-one (IIa) with diversely functionalized aldehydes (IIIa-IIIf). This synthetic approach provides a new and efficient tool for constructing novel heterocycles on newly synthesized substituted & alpha;,& beta;-unsaturated carbonyl compounds. The structures of all the synthesized products were confirmed with their elemental analysis, H-1 NMR, C-13 NMR, IR, and MS analysis. Further, the newly synthesized compounds were screened for in vitro antibacterial activity against G+ bacteria (S. aureus and B. subtili), G- bacteria (P. aeruginosa and C. albicans), antifungal activity against (C. albicans and A. niger) by using agar well diffusion method. Ciprofloxacin was used as a standard reference drug for antibacterial and Fluconazole drug was used for antifungal activity. The study reveals that the compounds (Ve), (Vf), (Vi), (Vk), and (Vl) showed potential activity against G+ bacteria, and compounds (Vc), (Ve), (Vi), (Vk), and (Vl) showed significant activity against G- bacteria. Compounds (Va), (Vc), (Ve), (Vf), (Vh), (Vi), (Vk), and (Vl) exhibited excellent potential against the antifungal activity.