One-Pot Synthesis of [1,2,3]Triazolo[1,5-a]quinoxalin-4(5H)-ones by a Metal-Free Sequential Ugi-4CR/Alkyne–Azide Cycloaddition Reaction

Yan, Yan‐Mei; Li, Hao-Yang; Zhang, Min; Wang, Rongxin; Zhou, Chenguang; Ren, Zhenxing; Ding, Ming‐Wu

doi:10.1055/s-0037-1610737

Cited by 7 publications

(2 citation statements)

References 13 publications

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“…Thus, either cyanamides 8a–d or tetrazoles 9a–d can be obtained from 1a–d just by tuning the amount of sodium azide. Overall, these routes allow the access to functionalized triazoloquinoxalines, compounds with interesting pharmacological properties, − without the involvement of a transition-metal − some of which are further decorated with a tetrazole ring …”

Section: Resultsmentioning

confidence: 99%

Intramolecular Cyclization of Azido-Isocyanides Triggered by the Azide Anion: An Experimental and Computational Study

et al. 2023

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This work describes the unprecedented intramolecular cyclization occurring in a set of α-azido-ω-isocyanides in the presence of catalytic amounts of sodium azide. These species yield the tricyclic cyanamides [1,2,3]triazolo[1,5-a]quinoxaline-5(4H)-carbonitriles, whereas in the presence of an excess of the same reagent, the azido-isocyanides convert into the respective C-substituted tetrazoles through a [3 + 2] cycloaddition between the cyano group of the intermediate cyanamides and the azide anion. The formation of tricyclic cyanamides has been examined by experimental and computational means. The computational study discloses the intermediacy of a long-lived N-cyanoamide anion, detected by NMR monitoring of the experiments, subsequently converting into the final cyanamide in the rate-determining step. The chemical behavior of these azido-isocyanides endowed with an aryl-triazolyl linker has been compared with that of a structurally identical azido-cyanide isomer, experiencing a conventional intramolecular [3 + 2] cycloaddition between its azido and cyanide functionalities. The synthetic procedures described herein constitute metal-free approaches to novel complex heterocyclic systems, such as [1,2,3]triazolo[1,5-a]quinoxalines and 9H-benzo[f]tetrazolo[1,5-d][1,2,3]triazolo[1,5-a][1,4]diazepines.

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Section: Resultsmentioning

confidence: 99%

Intramolecular Cyclization of Azido-Isocyanides Triggered by the Azide Anion: An Experimental and Computational Study

et al. 2023

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“…Reacting 2-azidobenzenamines 213, isocyanide 178, aldehydes, and propiolic acids 214 afforded [1,2,3]triazolo [1,5-a]quinoxalin-4(5H)-ones 216a-s via the formation of Ugi adducts 215. The cyclization occurs via an alkyne-azide cycloaddition reaction (Scheme 83) [71]. Gangaprasad et al [72] reported the syntheses of 1,2,3-triazole fused benzooxazepine and benzodiazepine analogs 218a-q via one-pot azide substitution and intramolecular azide-olefin 217 oxidative cycloaddition sequence under metal-free conditions (Scheme 84) [72].…”

Section: Entrymentioning

confidence: 99%

Azides in the Synthesis of Various Heterocycles

et al. 2022

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In this review, we focus on some interesting and recent examples of various applications of organic azides such as their intermolecular or intramolecular, under thermal, catalyzed, or noncatalyzed reaction conditions. The aforementioned reactions in the aim to prepare basic five-, six-, organometallic heterocyclic-membered systems and/or their fused analogs. This review article also provides a report on the developed methods describing the synthesis of various heterocycles from organic azides, especially those reported in recent papers (till 2020). At the outset, this review groups the synthetic methods of organic azides into different categories. Secondly, the review deals with the functionality of the azido group in chemical reactions. This is followed by a major section on the following: (1) the synthetic tools of various heterocycles from the corresponding organic azides by one-pot domino reaction; (2) the utility of the chosen catalysts in the chemoselectivity favoring C−H and C-N bonds; (3) one-pot procedures (i.e., Ugi four-component reaction); (4) nucleophilic addition, such as Aza-Michael addition; (5) cycloaddition reactions, such as [3+2] cycloaddition; (6) mixed addition/cyclization/oxygen; and (7) insertion reaction of C-H amination. The review also includes the synthetic procedures of fused heterocycles, such as quinazoline derivatives and organometal heterocycles (i.e., phosphorus-, boron- and aluminum-containing heterocycles). Due to many references that have dealt with the reactions of azides in heterocyclic synthesis (currently more than 32,000), we selected according to generality and timeliness. This is considered a recent review that focuses on selected interesting examples of various heterocycles from the mechanistic aspects of organic azides.

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Isocyanide–Based Multicomponent Reactions Coupled One–Pot Process: Efficient Tools to Diversity–Oriented Synthesis of Structural Peptidomimetics

Kaveti,

Rentería‐Gómez,

Corona‐Díaz

et al. 2024

ChemPlusChem

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Multicomponent diversity‐oriented synthesis (DOS) of conformationally anchored structural peptidomimetics like 2,5‐diketopiperazines (2,5‐DKP) containing heterocyclic bioisosteres of the amide bond, such as 1,2,3‐triazoles and 1,5‐disubstituted tetrazoles (1,5‐DS‐T) is described. Structural peptidomimetics are synthesized from similar available starting materials, via a strategy based on isocyanide‐based multicomponent reactions (IMCRs): Ugi‐4CR and Ugi‐Azide (UA), followed by a one‐pot process: SN2/intramolecular alkyne‐azide cycloaddition (IAAC). The sequential aligning of two powerful synthetic tools (IMCR and IAAC) has parallelly contributed to generate anchored conformation and complexity in target molecules, which are considered structural peptidomimetics of 2,5‐DKP. Herein, the 1,2,3‐triazole ring plays a key role in the preference for the boat conformation. Furthermore, the use of different IMCRs generates scaffold diversity at the N‐1 α‐carbon of the pyrazinone ring, replacing a linear amide bond with a heterocyclic bioisostere like 1,5‐DS‐T leading to the synthesis of novel tricyclic peptidomimetics. The DFT calculations confirmed the boat conformation of the synthesized molecules.

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One-Pot Synthesis of [1,2,3]Triazolo[1,5-a]quinoxalin-4(5H)-ones by a Metal-Free Sequential Ugi-4CR/Alkyne–Azide Cycloaddition Reaction

Cited by 7 publications

References 13 publications

Intramolecular Cyclization of Azido-Isocyanides Triggered by the Azide Anion: An Experimental and Computational Study

Intramolecular Cyclization of Azido-Isocyanides Triggered by the Azide Anion: An Experimental and Computational Study

Azides in the Synthesis of Various Heterocycles

Isocyanide–Based Multicomponent Reactions Coupled One–Pot Process: Efficient Tools to Diversity–Oriented Synthesis of Structural Peptidomimetics

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