title: New thiophene-1,2,4-triazole-5(3)-ones: highly bioactive thiosemicarbazides, structures of Schiff bases and triazole-thiols.
abstract: Key compound 2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4-tiazole-1-yl) acetohydrazide (3) was synthesized by reacting hydrazine hydrate with ethyl-2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4-tiazole-1yl)acetate (2), obtained in basic media from 4-amino-5-(thiophene-2-ylmethyl)-2H-1,2,4-triazole-3(4H)-one (1). Compound 3 was converted to thiosemicarbazide derivatives (4a-d) and Schiff base derivatives 6a-e and 7a-e. The treatment of compound 4 with NaOH gave 4-amino-2-((4-(4-aryl)-5-mercapto-4H-1,2,4-triazole-3-yl)methyl)-5-(thiophene-2-ylmethyl)-2H-1,2,4-triazole-3(4H)-ones (5a-d). All newly compounds, well characterized by elemental analyses, IR, (1)H NMR, (13)C NMR and mass spectral studies were tested for their antioxidant and antimicrobial activities. Thiosemicarbazide derivatives (4a-d) were highly active in two antioxidant tests with 69.0-88.2% DPPH· scavenging and 503-1257 μM TEAC values, while the others showed lower or no activity. The results of the two antioxidant tests correlated well. Moreover, Thiosemicarbazide derivatives (4a-d) also showed antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Mycobacterium smegmatis. Thiosemicarbazide group deserves attention in the synthesis of bioactive compounds.
authors: Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon, Turkey. Electronic address: unver.yasemincan@hotmail.com.
authors: Yasemin
authors: Y
authors: Ünver
authors: Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon, Turkey.
authors: Kemal
authors: K
authors: Sancak
authors: Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon, Turkey.
authors: Fatih
authors: F
authors: Çelik
authors: Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon, Turkey.
authors: Emrah
authors: E
authors: Birinci
authors: Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon, Turkey.
authors: Murat
authors: M
authors: Küçük
authors: Giresun University, Faculty of Arts and Sciences, Department of Physics, 28100 Giresun, Turkey.
authors: Serkan
authors: S
authors: Soylu
authors: Department of Nutrition and Dietetics, School of Health, Gümüşhane University, 29100 Gümüşhane, Turkey.
authors: Nesibe Arslan
authors: NA
authors: Burnaz
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D020102:Mycobacterium smegmatis / Q000187:drug effects; D012545:Schiff Bases / Q000737:chemistry*; D012663:Semicarbazides / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013876:Thiophenes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D014230:Triazoles / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D012545:Schiff Bases; D012663:Semicarbazides; D013438:Sulfhydryl Compounds; D013876:Thiophenes; D014230:Triazoles; C005151:thiosemicarbazide
keywords: 1,2,4-Triazole/thiol; Antimicrobial; Antioxidant; Schiff base; Thiosemicarbazide