scholarly journals Recent Progress of Cu-Catalyzed Azide-Alkyne Cycloaddition Reactions (CuAAC) in Sustainable Solvents: Glycerol, Deep Eutectic Solvents, and Aqueous Media

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2015 ◽  
Author(s):  
Noel Nebra ◽  
Joaquín García-Álvarez

This mini-review presents a general overview of the progress achieved during the last decade on the amalgamation of CuAAC processes (copper-catalyzed azide-alkyne cycloaddition) with the employment of sustainable solvents as reaction media. In most of the presented examples, the use of water, glycerol (Gly), or deep eutectic solvents (DESs) as non-conventional reaction media allowed not only to recycle the catalytic system (thus reducing the amount of the copper catalyst needed per mole of substrate), but also to achieve higher conversions and selectivities when compared with the reaction promoted in hazardous and volatile organic solvents (VOCs). Moreover, the use of the aforementioned green solvents also permits the improvement of the overall sustainability of the Cu-catalyzed 1,3-dipolar cycloaddition process, thus fulfilling several important principles of green chemistry.

2021 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  

<p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a widely used and effective chemical transformation, applied to obtain relevant products in medicine, biology and materials science. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as green and “active” reaction media, has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these innovative solvents has shown to improve the reaction effectiveness, giving excellent yields. NADESs proved to be “active” in these transformations for the absence of added bases in all the performed reactions and in several cases, for their reducing capabilities. The reactions outcomes were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering of reagents and the possibility of recycling of the green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis. </p>


2021 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  

<p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a widely used and effective chemical transformation, applied to obtain relevant products in medicine, biology and materials science. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as green and “active” reaction media, has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these innovative solvents has shown to improve the reaction effectiveness, giving excellent yields. NADESs proved to be “active” in these transformations for the absence of added bases in all the performed reactions and in several cases, for their reducing capabilities. The reactions outcomes were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering of reagents and the possibility of recycling of the green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis. </p>


2021 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  

<p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a widely used and effective chemical transformation, applied to obtain relevant products in medicine, biology and materials science. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as green and “active” reaction media, has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these innovative solvents has shown to improve the reaction effectiveness, giving excellent yields. NADESs proved to be “active” in these transformations for the absence of added bases in all the performed reactions and in several cases, for their reducing capabilities. The reactions outcomes were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering of reagents and the possibility of recycling of the green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis. </p>


Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 65 ◽  
Author(s):  
Loredana Maiuolo ◽  
Vincenzo Algieri ◽  
Fabrizio Olivito ◽  
Antonio De Nino

The use of eco-compatible synthetic procedures in organic reactions and, in particular, in 1,3-dipolar cycloaddition reactions, has recently received a great deal of attention and considerable progress has been achieved in this area in the last years. This review summarizes the approaches currently employed to synthesize heterocyclic compounds by catalyzed 1,3-dipolar cycloadditions in green solvents in the last six years. Our choice to do a selection of the literature from 2014 to 2019 was made considering the absence of a recent review about this period, to our knowledge. Several examples to construct heterocycles by 1,3-dipolar cycloadditions will be discussed in this work subdivided in function of the most important class of non-conventional and green solvents, i.e., ionic liquids (ILs), deep eutectic solvents (DES), and water.


2018 ◽  
Vol 7 (4) ◽  
pp. 353-359 ◽  
Author(s):  
Jing Wang ◽  
Sheila N. Baker

Abstract Ionic liquids (ILs) are considered to be green solvents for various applications. However, their synthesis via chemical reaction with by-products or waste produced is contradictory to the concept of green chemistry, and the purity problem and economic feasibility limit their applications in some large-scale industrial applications. 1-Butyl-1-methylpyrrolidinium bromide ([bmpy][Br]), which is a molten salt with melting point above 100°C is a precursor of pyrrolidinium ILs, but hardly can be put under the category of IL because of its high melting point. In this study, [bmpy][Br] based binary deep eutectic solvent (BDES) and ternary deep eutectic solvent (TDES) were synthesized to prepare [bmpy][Br] in liquid form. During the preparation process, no reaction media was employed, no by-product was generated, and no further purification was required, thereby making it a completely green process. The prepared TDES has better thermal stability and larger free volume than BDES, which is potentially useful for sorption applications with high temperature requirement. It is also because of the green preparation process that the TDES is also expected to be capable for the large-scale industrial applications. This work is opening up new avenues for the study of binary and ternary IL-DES system and their applications.


2020 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  

<div><div><div><p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a transformation widely used to obtain relevant products in chemical biology, medicinal chemistry, materials science and other fields. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as “active” reaction media has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these green liquids as green and catalytic solvents has shown to improve the reaction effectiveness, giving excellent yields. The NADESs proved to be “active” in this transformation for the absence of added bases in all the performed reactions and in several cases for their reducing capabilities. The results were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering</p></div></div></div><div><div><div><p>of reagents and the possibility of recycling of these green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis.</p></div></div></div>


Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 574 ◽  
Author(s):  
Luca Piemontese ◽  
Roberta Sergio ◽  
Federica Rinaldo ◽  
Leonardo Brunetti ◽  
Filippo M. Perna ◽  
...  

An unsubstituted 2-hydroxyphenylbenzimidazole has recently been included as a scaffold in a series of hybrids (including the hit compound PZ1) based on the framework of the acetylcholinesterase (AChE) inhibitor Donepezil, which is a new promising multi-target ligand in Alzheimer’s disease (AD) treatment. Building upon these findings, we have now designed and completed the whole synthesis of PZ1 in the so-called deep eutectic solvents (DESs), which have emerged as an unconventional class of bio-renewable reaction media in green synthesis. Under optimized reaction conditions, the preparation of a series of 2-hydroxyphenylbenzimidazole-based nuclei has also been perfected in DESs, and comparison with other routes which employ toxic and volatile organic solvents (VOCs) provided. The functionalization of the aromatic ring can have implications on some important biological properties of the described derivatives and will be the subject of future studies of structure-activity relationships (SARs).


2020 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  

<div><div><div><p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a transformation widely used to obtain relevant products in chemical biology, medicinal chemistry, materials science and other fields. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as “active” reaction media has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these green liquids as green and catalytic solvents has shown to improve the reaction effectiveness, giving excellent yields. The NADESs proved to be “active” in this transformation for the absence of added bases in all the performed reactions and in several cases for their reducing capabilities. The results were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering</p></div></div></div><div><div><div><p>of reagents and the possibility of recycling of these green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis.</p></div></div></div>


2021 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  

<p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a widely used and effective chemical transformation, applied to obtain relevant products in medicine, biology and materials science. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as green and “active” reaction media, has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these innovative solvents has shown to improve the reaction effectiveness, giving excellent yields. NADESs proved to be “active” in these transformations for the absence of added bases in all the performed reactions and in several cases, for their reducing capabilities. The reactions outcomes were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering of reagents and the possibility of recycling of the green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis. </p>


2021 ◽  
Author(s):  
Jeena N. Baby ◽  
Lavanya Chandrasekar ◽  
Sea-Fue Wang ◽  
Sriram Balasubramanian ◽  
Ashwini Anantharaman ◽  
...  

By serving as alternatives to toxic and hazardous solvents, green solvents assist in implementing the idea of sustainability. The use of these neoeric reaction media dramatically reduces energy requirements and...


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