Synthesis, Characterization, and Antimicrobial Evaluation of Some Novel 4-Hydroxyquinolin-2(1H)-ones

Abstract

Vilsmeier–Haack formylation of 3-acetyl-1-methyl-4-hydroxyquinolin-2(1H)-one (2) produced the novel 6-methyl-4,5-dioxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxaldehyde (3). Reactions of carboxaldehyde 3 with a diversity of nucleophilic reagents were studied and a variety of products were obtained via ring-opening, ring-closing (RORC) sequence. Also, some novel heteroannulated pyrano[3,2-c]quinolines were prepared. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data.

GRAPHICAL ABSTRACT

Keywords:

• Cyclocondensation
• 4-hydroxyquinolin-2(1H)-one
• pyrano[3,2-c]quinolinone
• RORC
• Vilsmeier–Haack reaction

ACKNOWLEDGMENT

The authors are very grateful to Department of Microbiology, Faculty of Agriculture, Al‐Azhar University for Girls, Nasr‐City, Cairo, Egypt, for performing the antimicrobial evaluation.

Notes

^a No inhibition.

Notes. L, low activity = mean of zone diameter ≤ 1/3 of mean zone diameter of control. I, intermediate activity = mean of zone diameter ≤ 2/3 of mean zone diameter of control. H, high activity = mean of zone diameter >2/3 of mean zone diameter of control. S, standard drug such as cephalothin in the case of Gram-positive bacteria, chloramphencol in the case of Gram-negative bacteria, and cycloheximide in the case of fungi.