title: Antimicrobial studies of some novel quinazolinones fused with [1,2,4]-triazole, [1,2,4]-triazine and [1,2,4,5]-tetrazine rings.
abstract: Three series of novel and new fused heterocyclic systems, viz. triazolo[4,3-a]-quinazolin-7-ones (4), [1,2,4,5]-tetrazino[4,3-a]-quinazolin-8-ones (6) and indolo[2,3-c][1,2,4]-triazino[4,3-a]-quinazolin-8-ones (8) have been synthesized from the key intermediate 3-(substituted-phenyl)-2-hydrazino-quinazolin-4-ones (3). Thus, condensation of (3) with appropriate aromatic acids in the presence of DCC in dichloromethane afforded the fused system (4), while reaction of (3) with isatin in methanol gave the corresponding Schiff base (7) which on cyclodehydration furnished another fused heterocyclic system (8). The intermediate (3) on refluxing with substituted-phenylisothiocyanate gave the substituted-thiosemicarbazide (5), which on oxidative cyclization with bromine in CCl(4) furnished the novel fused system (6). The structures of intermediate and final compounds have been determined by means of IR, (1)H NMR, (13)C NMR, UV and elemental analysis. All the synthesized compounds have been screened for their antibacterial activity against gram-negative bacteria, Escherichia coli, Pseudomonas aeruginosa and gram-positive bacteria, Streptococcus pneumoniae, Bacillus subtilis, as well as demonstrated significant antifungal activity against fungi viz. Candida albicans, Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger.
authors.affiliation: Department of Chemistry, D.D.U. Gorakhpur University, Civil Lines, Gorakhpur 273001, Uttar Pradesh, India. skpandey1982@yahoo.co.in
authors.forename: Sarvesh Kumar
authors.initials: SK
authors.lastname: Pandey
authors.forename: Abhishek
authors.initials: A
authors.lastname: Singh
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Singh
authors.lastname: Nizamuddin
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D005658:Fungi / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D052999:Quinazolinones / Q000737:chemistry / Q000494:pharmacology*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D014227:Triazines / Q000737:chemistry*; D014230:Triazoles / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D052999:Quinazolinones; D014227:Triazines; D014230:Triazoles