title: 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.
authors.affiliation: Department of Chemistry, Faculty of Women, Ain Shams University , Heliopolis, Cairo , Egypt.
authors.forename: Nadia G
authors.initials: NG
authors.lastname: Kandile
authors.forename: Howida T
authors.initials: HT
authors.lastname: Zaky
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D000935:Antifungal Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D001230:Aspergillus / Q000187:drug effects / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development; D002384:Catalysis; D002701:Chloramphenicol / Q000494:pharmacology; D013293:Enterococcus faecalis / Q000187:drug effects / Q000254:growth & development; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D009761:Nystatin / Q000494:pharmacology; D010880:Piperidines / Q000737:chemistry*; D011724:Pyridazines / Q000138:chemical synthesis* / Q000494:pharmacology; D011743:Pyrimidines / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D013329:Structure-Activity Relationship; D013777:Tetrazoles / Q000737:chemistry; D013843:Thiazines / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D010880:Piperidines; D011724:Pyridazines; D011743:Pyrimidines; D013777:Tetrazoles; D013843:Thiazines; D009761:Nystatin; D002701:Chloramphenicol; C032727:piperidine
keywords: Antimicrobial activity; dimruth rearrangement; intermolecular cyclization; tetrazole