Selenium Dioxide–Mediated Synthesis of Fused 1,2,4-Triazoles as Cytotoxic Agents

Synthesis methods of 1,2,3-/1,2,4-triazoles: A review

Triazole, comprising three nitrogen atoms and two carbon atoms, is divided into two isomers 1,2,3-triazole and 1,2,4-triazole. Compounds containing a triazole are one of the significant heterocycles that exhibit broad biological activities, such as antimicrobial, analgesic, anti-inflammatory, anticonvulsant, antineoplastic, antimalarial, antiviral, antiproliferative, and anticancer activities. A great quantity of drugs with a triazole structure has been developed and proved, for example, ketoconazole and fluconazole. Given the importance of the triazole scaffold, its synthesis has attracted much attention. This review summarizes the synthetic methods of triazole compounds from various nitrogen sources in the past 20 years.

Nitroalkanes as electrophiles: synthesis of triazole-fused heterocycles with neuroblastoma differentiation activity

We discovered a reaction of nitroalkanes with 2-hydrazinylquinolines, 2-hydrazinylpyridines and bis-2,4-dihydrazinylpyrimidines in polyphosphoric acid (PPA) affording 1,2,4-triazolo[4,3-a]quinolines, 1,2,4-triazolo[4,3-a]pyridines and bis[1,2,4]triazolo[4,3-a:4',3'-c]pyrimidines, respectively. The reaction expands the scope of heterocyclic annulations involving phosphorylated nitronates, believed to be the electrophilic intermediates formed from nitroalkanes in PPA. Several of the synthesized triazoles showed promising anticancer activity by inducing differentiation in neuroblastoma cancer cells. Due to the urgent need for novel differentiation agents for neuroblastoma therapy, this finding warrants further evaluation of this class of compounds against neuroblastoma.

Recent progress in selenium-catalyzed organic reactions

Selenium-based catalysts, including organo- and inorganoselenium ones, in organic synthesis in the recent decade are reviewed.