title: Synthesis of some new 1,2,4-triazoles, their Mannich and Schiff bases and evaluation of their antimicrobial activities.
abstract: 4-Phenyl-5-pyridin-4-yl-4H-1,2,4-triazole-3-thiol (3) was obtained in basic media via the formation of 2-isonicotinoyl-N-phenylhydrazinecarbothioamide (2), and converted to some alkylated derivatives (4a,b) and Mannich base derivatives (5a-c). 2-[(4-Phenyl-5-pyridin-4-yl-4H-1,2,4-triazol-3-yl)thio]acetohydrazide (7) that was obtained by using compound 3 as precursor in two steps was converted to thiosemicarbazide derivative (8), Schiff base derivatives (9) and 5-{[(4-phenyl-5-pyridin-4-yl-4H-1,2,4-triazol-3-yl)thio]methyl}-1,3,4-oxadiazole-2-thiol (10). Moreover, 5-{[(4-phenyl-5-pyridin-4-yl-4H-1,2,4-triazol-3-yl)thio]methyl}-3-{[(2-morpholin-4-ylethyl)amino]methyl}-1,3,4-oxadiazole-2(3H)-thione (11) was synthesized via reaction of compound 10 with 2-(4-morpholino)ethylamine. The treatment of compound 8 with NaOH gave 4-(4-methylphenyl)-5-{[(4-phenyl-5-pyridine-4-yl-4H-1,2,4-triazol-3-yl)thio]methyl}-4H-1,2,4-triazole-3-thiol (12), while the acidic treatment of compound 8 afforded 5-{[(4-phenyl-5-pyridin-4-yl-4H-1,2,4-triazol-3-yl)thio]methyl}-2(4-methylphenyl)-amino-1,3,4-thiadiazole (14). N-Methyl derivative of compound 14 and a Mannich base derivative of compound 12 were synthesized from the reactions of these precursors with methyl iodide and methyl piperazine, respectively. All newly synthesized compounds were screened for their antimicrobial activities. The antimicrobial activity study revealed that all the compounds screened showed good or moderate activity except compounds 3, 5c, 7, 9c, 9e, 9g, 9h, 11, and 13.
authors.affiliation: Karadeniz Technical University, Department of Chemistry, 61080 Trabzon, Turkey.
authors.forename: Hacer
authors.initials: H
authors.lastname: Bayrak
authors.forename: Ahmet
authors.initials: A
authors.lastname: Demirbas
authors.forename: Sengül Alpay
authors.initials: SA
authors.lastname: Karaoglu
authors.forename: Neslihan
authors.initials: N
authors.lastname: Demirbas
mesh_terms: D000890:Anti-Infective Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008352:Mannich Bases / Q000737:chemistry*; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D012545:Schiff Bases / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014230:Triazoles / Q000138:chemical synthesis* / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D008352:Mannich Bases; D012545:Schiff Bases; D014230:Triazoles