Synthesis, reaction, antimicrobial, and docking study of new chalcones incorporating isoquinoline moiety

Abstract

Reaction of isoquinoline 1 with hydrazonoyl chlorides 2A–E gave the corresponding triazoloisoquinolines 4A–E. The latter products 4A–E were reacted with 4-(piperidin-1-yl)benzaldehyde 5a and 4-morpholinobenzaldehyde 5b to afford the corresponding chalcones 6a,b. Some of chalcones 6 were reacted with hydrazine hydrate in refluxing ethanol to give the corresponding 8,9-dimethoxy-1-aryl-4,5-dihydro-1H-pyrazol-3-yl-1,5,6,10b-tetrahydro-[1,2,4]triazolo[3,4-a]isoquinoline derivatives 7A–C. Antimicrobial studies were performed using gram-negative bacteria (Escherichia coli) and (Klebsiella pneumonia), a gram-positive bacteria (Streptococcus mutans) and (Staphylococcus aureus), filamentous fungus (Asperagillus Nigar) and yeast (Candida albicans). Data revealed that chalcone 6Aa achieved the lowest MIC values (high efficient derivative) against the sensitive bacterial strain E. coli with MIC value 130 µg/ml. The most effective compound 6Aa, which demonstrated the highest binding affinity toward tested protein [thymidine phosphorylase enzyme, (PDB ID:4EAD)], was docked using MOE 2014.09 software.