Chiral Fused 1,2,3‐Triazoles: A Synthetic Overview

Abstract

Triazoles have always occupied a pivotal position in the field of medicinal and pharmaceutical chemistry. Recently, the area of chiral fused triazoles has gained attention. The synthetic routes to access chiral fused triazole may involve either a natural or synthetic chiral starting material with a suitably functionalized azide and alkyne component or isomer resolution to achieve chirality. Asymmetric synthesis methods using chiral complexes and organocatalysis have also emerged for obtaining chiral fused triazoles. Herein, we have described an up-to-date overview of different synthetic protocols applied to construct chiral fused 1,2,3-triazoles. Scheme 1. Basic methodologies for triazole construction. 2 3 4 5 6 7 8 . Yanai's stereo-divergent synthesis of ido-triazole ent-6 a and gluco-triazoles 7 a. Scheme 3. Yanai's diastereo-divergent synthesis of manno-, gulo-, galacto-and altro-triazoles. . Konda's synthesis of tricyclic triazolo-oxazepines 62. Scheme 15. Cobb's synthesis of spirocyclic triazolooxazine nucleosides 67. Scheme 16. Sen's synthesis of tetracyclic triazolo-oxazepines 69. to azide group and protected amine was propargylated to access azido-alkynes 122 c-h for triazole formation 124 (Scheme 29). The copper catalyzed version of this step was also carried out that gave almost approximately same yields in lesser Scheme 25. Chrandrasekaran's synthesis of triazolo-pyrazines and pyrazinones from amino acid derived sulfamidates. Scheme 26. Chrandrasekaran's synthesis of triazolo-pyrazinone 110 having pendant amino acid.structural features of triazoles, the authors carried out one pot hydrogenation and insitu Boc-protection of 155 a, followed by azidation and propargylation to afford azido-alkyne 160. Subsequently, thermal azide-alkyne cycloaddition furnished the triazole product 161 in good yield (Scheme 34).Allenyl silanes are extensively used in synthetic organic transformations and provide ready access to enantiopure pyrroles, oxiranes, furans and vinyl silanes. In lewis acid assisted reaction, allenyl silanes work as propargyl anion equivalents. Allenyl silane forms regioselective homopropargylic alcohol when treated with aldehyde and ketone. The stabilization is Scheme 31. Thomas's synthesis of steroidal fused 1,2,3-triazoles.Scheme 32. Thomas's synthesis of steroidal fused NH-1,2,3-triazoles and steroidal 4,5-fused triazolo-alkynes.

Nanomagnetic macrocyclic Schiff-base–Mn(ii) complex: an efficient heterogeneous catalyst for click approach synthesis of novel β-substitued-1,2,3-triazoles

“…Moreover, the presence of a broad peak at 2 θ = 20–27° which is due to the amorphous silicon layer, demonstrating that the Fe 3 O 4 structure was functionalized by CPTMS linker. 26,27 In addition, after anchoring the [PAM–Schiff base–Mn][ClO 4 ] complex, the new diffraction peaks were appeared at 2 θ = 32–35; 40–42 and 59–61°, that are related to a separate phase of Mn species in [Fe 3 O 4 @PAM–Schiff base–Mn][ClO 4 ], confirming the complexation of Mn and its strong attachment over Fe 3 O 4 @PAM–Schiff-base composite. 89,90 Finally, based on the Scherrer ( D = Kλ /( β cos θ )) equation, the average crystallite size of [Fe 3 O 4 @PAM–Schiff base–Mn][ClO 4 ] nanoparticles was found to be about 17.42 nm.…”

Design and Synthesis of New 5-aryl-4-Arylethynyl-1H-1,2,3-triazoles with Valuable Photophysical and Biological Properties

“…In recent years, 1 H -1,2,3-Triazoles are of increasing interest to researchers as one of the most promising classes of heterocyclic compounds for different purposes of bioconjugation [ 1 ] design of new catalysts [ 2 ], supramolecular ensembles [ 3 , 4 ], and polymeric materials [ 5 ]. 1,2,3-Triazoles are widely synthetically available compounds due to the development of simple and effective methods of their preparation on the base of “click” reaction of Cu-catalyzed azide–alkyne cycloaddition (CuAAC) [ 6 , 7 , 8 , 9 , 10 ]. Due to the wide range of available derivatives and the accessibility of structural modifications by a variety of pharmacophore fragments 1,2,3-triazoles attract a special interest in the field of drug design [ 11 , 12 , 13 , 14 ].…”

Progress in the Synthesis of Fused 1,2,3‐Triazoles

“…Reddy et al [36a,9c] . synthesized chiral triazolo[1,5‐ a ][1,4]diazepines 102 via six centered Ugi reaction [36b] between benzylamine 97 , alkyl isocyanide 99 , phenyl propiolic acid 100 and sugar azidoaldehyde 98 to produce azide‐alkyne intermediate 101 followed by Huisgen thermal cycloaddition.…”