title: Studies on anti-MRSA parenteral cephalosporins. I. Synthesis and antibacterial activity of 7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)- hydroxyiminoacetamido]-3-(substituted imidaz.
abstract: In order to improve the antibacterial activity of cefozopran (CZOP) against methicillin-resistant Staphylococcus aureus (MRSA), we initiated chemical modification to introduce a 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-hydroxyimino acetyl group at the C-7 position and a 3- or 6-substituted imidazo[1,2-b]pyridazinium or 5-substituted imidazo[1,2-a]pyridinium group at the C-3' position. Although this approach successfully enhanced the anti-MRSA activity of CZOP two to eight times, a slight decrease in the activity against Gram-negative bacteria including Pseudomonas aeruginosa was involved. Among the novel derivatives, 3-(6-aminoimidazo[1,2-b]pyridazinium-1-yl)methyl-7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)hydroxyiminoacetamido]-3-cephem-4-carboxylate (44a) showed an excellent balance of activity against MRSA and Gram-negative bacteria.
authors.affiliation: Pharmaceutical Research Division, Takeda Chemical Industries, Ltd., Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Iizawa
authors.forename: K
authors.initials: K
authors.lastname: Okonogi
authors.forename: A
authors.initials: A
authors.lastname: Miyake
mesh_terms: D000818:Animals; D002511:Cephalosporins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D016106:Methicillin Resistance; D051379:Mice; D008813:Mice, Inbred ICR; D008826:Microbial Sensitivity Tests / Q000379:methods; D010091:Oximes / Q000737:chemistry; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects*; D013329:Structure-Activity Relationship; D000097586:Cefozopran
chemical_list: D002511:Cephalosporins; D010091:Oximes; D000097586:Cefozopran