1,2,3-Triazoles

Ruthenium-Catalyzed Azide Alkyne Cycloaddition Reaction: Scope, Mechanism, and Applications

“…As Ru(II) is known to catalyze reactions involving alkynes, 51 Fokin and Jia reasoned that a ruthenium(II) complex could perhaps be applied towards the synthesis of 1,2,3-triazoles via a cycloaddition reaction using an alkyne in a similar manner to the CuAAC reaction. 12 Initial catalyst screening, using the reaction of benzyl azide with phenylacetylene as a test system, showed that triazoles were indeed formed when heating all components in benzene at 80 A full investigation of the scope and limitations of this reaction was then carried out as part of this initial report 12 as well as in an ensuing publication a few years later, where also RuH 2 (CO)(PPh 3 ) 3 was reported to afford the 1,4-regioisomer. 27 Certain aspects of these initial studies, concerning the substrate scope as well as the catalysts that have been evaluated, are covered in more detail in other sections below, but a summary of these two seminal papers will be given here.…”

“…Regiochemical outcome using different Ru-catalysts 12 Conditions: 5 mol% catalyst, benzene, 80 °C, 4 h. Reactions with Ru(OAc) 2 (PPh 3 ) 2 , RuHCl(CO)(PPh 3 ) 3 and CpRuCl(PPh 3 ) 2 afforded low yields.…”

Studies with 2-arylhydrazononitriles: a new convenient synthesis of 2, 4-disubstituted- 1,2,3-triazole-5-amines

“…Owing to their importance an impressive number of work has been published on the chemistry and synthesis of 1,2,3-triazoles [5][6][7][8][9][10][11][12][13][14][15][16] . However, literature inspection indicated lack of efficient synthetic approach to 2-substituted-1,2,3-triazoleamines [15] . Cyclization of 2-arylhydrazonooximes into 1,2,3-triazole oxides has been reported some time ago [15] .…”

“…However, literature inspection indicated lack of efficient synthetic approach to 2-substituted-1,2,3-triazoleamines [15] . Cyclization of 2-arylhydrazonooximes into 1,2,3-triazole oxides has been reported some time ago [15] . Moreover the acetylated derivative of Mesoaldehyde 1,3-dioxime-2-arylhydrazone has been reported to cyclise in acetic acid in presence of CsCO 3 into 1,2,3-triazole [17] .…”

Synthesis of 6-Amino-5-cyano-1,4-disubstituted-2(1H)-Pyrimidinones via Copper-(I)-catalyzed Alkyne-azide ‘Click Chemistry’ and Their Reactivity

“…Amongst the various classes of nitrogen heterocycles, 1,2,3-triazoles and their derivatives deserve special recognition due to their wide usage in industrial applications as dyes, photographic materials, corrosion inhibitors and as herbicidal, fungicidal and antibacterial agrochemicals [5,6]. Several members of the 1,2,3-triazole family exhibit a broad spectrum of antiinfectious properties such as antimicrobial [7], anti-HIV [8], anti-allergic [9] and antimalarial activities [10].…”