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
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.