Synthesis and Evaluation of Bioactivity of Thiazolo[3,2‐b]‐[1,2,4]‐triazoles and Isomeric Thiazolo[2,3‐c]‐[1,2,4]‐triazoles

Abstract

Synthesis of 2‐(o‐nitrophenyl)‐6‐arylthiazolo[3,2‐b]‐[1,2,4]‐triazoles 4 and its isomer 3‐(o‐nitrophenyl)‐5‐arylthiazolo[2,3‐c]‐[1,2,4]‐triazoles 6 has been achieved starting from the appropriate 1‐(o‐nitrobenzoyl)‐3‐thiosemicarbazide 1. Compound 1 on condensation with α‐haloketones gives 2‐(o‐nitrobenzoyl)hydrazino‐4‐arylthiazole hydrobromide 5, which, on cyclization with POCl3, affords thiazolo[3,2‐b]‐[1,2,4]‐triazoles 6 and not the isomeric thiazolo[3,2‐b]‐[1,2,4]‐triazoles 4. This has been established by an unequivocal synthesis of 4 through polyphosphoric acid cyclization of 5‐aroylmethylmercapto‐3‐o‐nitrophenyl‐[1,2,4]‐triazole 3. Compound 3 was synthesized by condensation of α‐haloketones with 5‐mercapto‐3‐(o‐nitrophenyl)‐[1,2,4]‐triazole 2, obtained cyclization of 2‐(o‐nitrobenzoyl)hydrazinecarbothioamide 1 with NaOH. The antibacterial and antifungal activities of some of the compounds have also been evaluated.

Design, Synthesis, Characterization and Antimicrobial Evaluation of Some Heterocyclic Condensed Systems with Bridgehead Nitrogen from Thiazolotriazole Class

“…The fusion of triazole and thiazole rings can lead to thiazolotriazoles with superior biological properties due to mutual influence of the pharmacophores centers present in the molecule. Thus, literature data indicate that numerous thiazolo [3,2-b] [1,2,4] triazoles derivatives have been reported to possess antibacterial, [3][4][5][6][7][8][9] antifungal, 3,[6][7][8][9] anti-inflammatory, 3,10,11) analgesic, 3,10) antiproliferative, 12) anticonvulsant 13) properties. Also, thiazolo [3,2-b][1,2,4] triazol-ones have been studied for their properties with respect to their biological activities including anti-inflammatory, [14][15][16][17] analgesic, 15,17) anticancer, [18][19][20] antibacterial, 21) antifungal 21) and anticonvulsant.…”

Fused bicyclic 1,2,4‐triazoles with one extra sulfur atom: Synthesis, properties, and biological activity

“…[36] Synthesis of thiazolo [3,2-b] [1,2,4]triazoles 1 proceeds through oxidative alkylation by acid condensation and MW radiation (Scheme 1). [37,38] 2-Chloroacetic acid is also used as an alkylating agent in reactions with 1,2,4-triazole-3-thiones. [39,40] As a consequence, thiazolo [3,2-b] [1,2,4]triazolones 2 were obtained.…”

“…The development of effective routes for obtaining new fused triazoles is relevant because of their wide range of bioactivity and as a consequence-great perspective for usage. Obtained compounds exhibit fungicidal, [26,37,39,[46][47][48] antimicrobial, [26,[37][38][39][46][47][48]56] analgesic, [27,34,[42][43][44] antinociceptive, [28] ulcerogenic, [28,43] antioxidant, [27,39] antiinflammatory, [27][28][29]34,[42][43][44] and anticancer [41] activity. Thiazolo [3,2-b] [1,2,4]triazoles have the ability to act as a urease inhibitor, [36] stabilizers of G-quadruplex [32] and may be used as cationic surfactants.…”

“…Some representatives showed good activity with the minimal inhibitory concentration in the range of 100 to 200 mg/mL. [37] The antifungal activity of structure 4 was investigated. [47] triazole-5-yl)acetimides 5 were screened for their antifungal activity against Aspergillus flavus, Aspergillus fumigatus, Penicillium marneffei and Trichophyton mentagrophytes.…”

Synthesis and Biological Activity of 1,2,4-Triazolo-[3,4-b]Thiadiazole as Antimicrobial Agents

“…Among these, heterocyclic compounds have been given special importance because of a wide variety of biological properties associated with them. The importance of heterocycles in biological systems encouraged chemists to design and modify new heterocyclic compounds [1,2]. During the last two decades, the chemistry of 1,2,4-triazole and 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole and their derivatives have received considerable attention owing to their synthetic and effective biological importance [3][4][5].…”