Selectivities in 1,2,3-triazolide displacements of halides and additions to alkynes

Five‐Membered Heterocycles with Three Heteroatoms: Triazoles

“…12.1.5.2 Reactions of Nitrogen of 1,2,3-Triazoles 1H-1,2,3-Triazoles can be N-alkylated with alkyl halides in the presence of bases such as sodium alkoxide, sodium hydride, or sodium hydroxide to give mixtures of 1-and 2-alkylated-1H-1,2,3-triazoles [112]. Selectivity for alkylation at the 1-position has been achieved in the presence of silver or thallium salts of 1,2,3-triazoles on reaction with alkyl halides [113].…”

Diarylborinic Acid-Catalyzed Regioselective Ring Openings of Epoxy Alcohols with Pyrazoles, Imidazoles, Triazoles, and Other Nitrogen Heterocycles

“…The selectivity pattern observed for benzotriazole (N1 selectivity for the nucleophile and C3 selectivity for the electrophile) was found to hold for the parent 1,2,3-triazole, a significant observation given that base-mediated alkylations typically result in mixtures of N1-and N2-substituted products. 19 Triazolopyridine underwent selective alkylation at N1 [>9:1 N1:(N2 + N3), product 4c], whereas 5-trifluoromethyl-substituted benzotriazole gave a mixture of the N1-and N3-alkylated isomers 4d and 4d′. Pyrazoles proved to be particularly suitable reaction partners, resulting in yields ranging from 86% to 93% and >19:1 C3:C4 regioselectivities for epoxide ring opening (products 4e−4h).…”

Synthesis, Characterization, and Structural Investigations of 1‐Amino‐3‐substituted‐1,2,3‐triazolium Salts, and a New Route to 1‐Substituted‐1,2,3‐triazoles.

“…The chemistry of N-substituted-1,2,3-triazoles has been well developed due to its high biological activity, however, the preparation of isomerically pure N-substituted-1,2,3triazoles is not trivial [1][2][3][4][5][6][7][8][9][10][11][12]. Direct alkylation of 1H-1,2,3triazoles usually forms mixtures of 1-and 2-substituted 1,2,3-triazoles [8,11], which are often difficult to separate, and once formed often undergo isomerization equilibria in solution [7,10,12]. Cycloaddition reactions usually lead to 1-substituted-1,2,3-triazoles [9][10][11][12][13][14], however this synthetic route is complicated by the use of hazardous reagents, e.g.…”

“…Direct alkylation of 1H-1,2,3triazoles usually forms mixtures of 1-and 2-substituted 1,2,3-triazoles [8,11], which are often difficult to separate, and once formed often undergo isomerization equilibria in solution [7,10,12]. Cycloaddition reactions usually lead to 1-substituted-1,2,3-triazoles [9][10][11][12][13][14], however this synthetic route is complicated by the use of hazardous reagents, e.g. organic azides and acetylenic materials.…”

“…Cycloaddition reactions usually lead to 1-substituted-1,2,3-triazoles [9][10][11][12][13][14], however this synthesis route is complicated by the use of hazardous reagents, e.g. organic azides and acetylenic materials.…”