Synthesis of 2,5-diaryl-4-halo-1,2,3-triazoles and comparative study of their fluorescent properties

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.

4,5-Bis(arylethynyl)-1,2,3-triazoles-A New Class of Fluorescent Labels: Synthesis and Applications

Cu-catalyzed 1,3-dipolar cycloaddition of ethyl 2-azidoacetate to iodobuta-1,3-diynes and subsequent Sonogashira cross-coupling were used to synthesize a large series of new triazole-based push–pull chromophores: 4,5-bis(arylethynyl)-1H-1,2,3-triazoles. The study of their optical properties revealed that all molecules have fluorescence properties, the Stokes shift values of which exceed 150 nm. The fluorescent properties of triazoles are easily adjustable depending on the nature of the substituents attached to aryl rings of the arylethynyl moieties at the C4 and C5 atoms of the triazole core. The possibility of 4,5-bis(arylethynyl)-1,2,3-triazoles’ application for labeling was demonstrated using proteins and the HEK293 cell line. The results of an MTT test on two distinct cell lines, HEK293 and HeLa, revealed the low cytotoxicity of 4,5-bis(arylethynyl)triazoles, which makes them promising fluorescent tags for labeling and tracking biomolecules.

2H-Bis-1,2,3-triazolo-isoquinoline: Design, Synthesis, and Photophysical Study

An efficient three-step synthesis of a new heterocyclic system is described wherein the 2H-bis([1,2,3]triazolo)[5,1-a:4',5'-c]isoquinoline ring system is elaborated using a simple synthetic strategy. The approach permits the preparation of target compounds in high yields using readily available arylhydrazines and o-alkynylbenzaldehydes as starting materials. The photophysical properties of the prepared heterocycles were studied to demonstrate that the prepared compounds are attractive blue-emitting fluorophores, exhibiting quantum yields up to 98% and Stokes shifts up to 67 nm. A strong effect of the steric hindrance on the absorption and emission spectra was revealed.