title: Microwave assisted synthesis and structure-activity relationship of 4-hydroxy-N'-[1-phenylethylidene]-2H/2-methyl-1,2-benzothiazine-3-carbohydrazide 1,1-dioxides as anti-microbial agents.
abstract: A series of 4-hydroxy-N'-[1-phenylethylidene]-2H/2-methyl, 1,2-benzothiazine-3-carbohydrazide 1,1-dioxides was synthesized from commercially available sodium saccharin. Base catalyzed ring expansion of methyl (1,1-dioxido-3-oxo-1,2-benzisothiazol-2(3H)-yl)acetate followed by ultrasound mediated hydrazinolysis and subsequent reaction with 1-phenylethanones under the influence of microwaves yielded the title compounds. Besides, microwave assisted synthesis of 1,4-dihydropyrazolo[4,3-c][1,2]benzothiazin-3-ol 5,5-dioxide and 4-methyl-1,4-dihydropyrazolo[4,3-c][1,2]benzothiazin-3-ol 5,5-dioxide is also discussed. Most of the synthesized compounds were found to possess moderate to significant anti-microbial (anti-bacterial and anti-fungal) activities. It is found that compounds with greater lipophilicity (N-methyl analogues) possessed higher anti-bacterial activities.
authors.affiliation: Institute of Chemistry, University of the Punjab, Lahore 54590, Pakistan.
authors.forename: Naveed
authors.initials: N
authors.lastname: Ahmad
authors.forename: Muhammad
authors.initials: M
authors.lastname: Zia-ur-Rehman
authors.forename: Hamid Latif
authors.initials: HL
authors.lastname: Siddiqui
authors.forename: Muhammad Fasih
authors.initials: MF
authors.lastname: Ullah
authors.forename: Masood
authors.initials: M
authors.lastname: Parvez
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D018360:Crystallography, X-Ray; D004305:Dose-Response Relationship, Drug; D005658:Fungi / Q000187:drug effects*; D006834:Hydrazines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008872:Microwaves; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013843:Thiazines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D006834:Hydrazines; D013843:Thiazines