New pyrano[2,3-c]pyridazine derivatives with antimicrobial activity synthesized using piperidine as the organocatalyst

Abstract

A simple and efficient method for the synthesis of highly diverse pyrano [2,3-c]pyridazines was achieved by a one pot multicomponent reaction using piperidine as the organocatalyst. The synthesis of a series of heterocyclic derivatives with varying functionality (e.g. thiazine, tetrazole and pyrimidine) incorporating the pyrano[2,3-c]pyridazine moiety were achieved via reaction of 2a-e with different reagents. The structures of the synthesized derivatives were elucidated by FTIR, MS, 1 H and 13 C NMR spectroscopy. A number of the newly synthesized targeted compounds 2b-e, 3a-c and 4a-c were evaluated for their in vitro antibacterial activity and were compared with chloramphenicol and nystatin as broad spectrum reference standard antibiotics. Tests were carried out against Staphylococcus aureus (MTCC3160) and Enterococcusi fecalis as Gram-positive bacteria, and Escherichia coli (MTCC1652) and Klebsiella pneumonia as Gram-negative bacteria. Antifungal potential against Candida albicans, and Aspergillus albicans strains were also evaluated. The results revealed that compounds 3a and 3c showed strong significant activity relative to the reference against these bacterial and fungal strains.

Palladium‐catalyzed synthesis of novel pyrido[3,4‐d]pyridazin‐1(2H)‐ones as promising α‐glucosidase, α‐amylase and EGFR inhibitors along with molecular docking

“…The pyridazine‐3(2 H )‐one unit was first reported by E. Fischer by the cyclizing phenylhydrazone of levulinic acid, followed by the oxidation by PCl 5 . [ 1 ] Many pyridazine derivatives were found to have acetylcholinesterase inhibitor, [ 2 ] anti‐inflammatory, [ 3 ] antibacterial, [ 4 ] analgesic, [ 5 ] anticonvulsant, [ 6 ] and antioxidant [ 7 ] activities. Furthermore, some reported pyridazine compounds are key intermediates in the synthesis of prizidilol, which have vasodilator and beta‐blocking properties.…”

Current Research on Antiepileptic Compounds

“…It contains a six-membered ring with two adjacent nitrogen atoms, and is aromatic [150]. Pyridazine derivatives have various biological applications [152][153][154][155].…”