title: Syntheses and evaluation of antioxidant activity of sydnonyl substituted thiazolidinone and thiazoline derivatives.
abstract: 3-Aryl-4-formylsydnone 4'-phenylthiosemicarbazones (3a-d) and 3-aryl-4-formylsydnone thiosemicarbazones (3e-h), which are precursors of 3-aryl-4-heterocyclic sydnones, are prepared by the condensation of 3-aryl-4-formylsydnones (1a-d) with 4'-phenylthiosemicarbazide (2a) and thiosemicarbazide (2b), respectively. The thiosemicarbazones 3 reacted with cyclic reagents such as ethyl chloroacetate (4a), ethyl 2-chloroacetoacetate (4b) and 2-bromoacetophenone (4c) to produce heterocyclic substituted sydnone derivatives 5-7 that possess 4-oxo-thiazolidine and thiazoline groups. The antioxidant activity of synthesized compounds 5a-7h was evaluated. Among these compounds, 4-methyl-2-[(3-arylsydnon-4-yl-methylene)hydrazono]-2,3-dihydro-thiazole-5-carboxylic acid ethyl ester (6e-h) and 4-phenyl-2-[(3-arylsydnon-4-yl-methylene)hydrazono]-2,3-dihydro-thiazoles (7e-h) exhibit the potent DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, comparable to that of vitamin E.
authors.affiliation: Department of Chemical Engineering, Southern Taiwan University of Technology, 1 Nan-Tai St. Yung-Kang, Tainan 710, Taiwan, ROC. meihsius@mail.stut.edu.tw
authors.forename: Mei-Hsiu
authors.initials: MH
authors.lastname: Shih
authors.forename: Fang-Ying
authors.initials: FY
authors.lastname: Ke
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000138:chemical synthesis / Q000494:pharmacology; D000975:Antioxidants / Q000138:chemical synthesis* / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology; D003500:Cyclization; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000494:pharmacology; D006834:Hydrazines / Q000494:pharmacology; D010851:Picrates; D013329:Structure-Activity Relationship; D013830:Thiadiazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D013882:Thiosemicarbazones / Q000138:chemical synthesis* / Q000494:pharmacology; D014810:Vitamin E / Q000494:pharmacology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006834:Hydrazines; D010851:Picrates; D013830:Thiadiazoles; D013882:Thiosemicarbazones; D014810:Vitamin E; C004931:1,1-diphenyl-2-picrylhydrazyl