Synthesis of 1,2,3-triazolylpyranosides through click chemistry reaction

The use of ultrasound in the South Cone region. Advances in organic and inorganic synthesis and in analytical methods

In organic and inorganic synthesis and in analytical methods, an external conventional heat source is usually applied to carry out a chemical reaction at a high temperature, or an extraction procedure. In the last decades, the use of ultrasound as an alternative energy source has become an interesting field of research in these topics in the South Cone region (Argentina, Chile, Uruguay, Southern Brazil and Paraguay). For this reason, the present review, covering the period 2009 to mid-2021, is a compilation of ultrasound-assisted synthetic and analytical methodologies.

Cu(I)-Catalyzed Click Chemistry in Glycoscience and Their Diverse Applications

Copper(I)-catalyzed 1,3-dipolar cycloaddition between organic azides and terminal alkynes, commonly known as CuAAC or click chemistry, has been identified as one of the most successful, versatile, reliable, and modular strategies for the rapid and regioselective construction of 1,4-disubstituted 1,2,3-triazoles as diversely functionalized molecules. Carbohydrates, an integral part of living cells, have several fascinating features, including their structural diversity, biocompatibility, bioavailability, hydrophilicity, and superior ADME properties with minimal toxicity, which support increased demand to explore them as versatile scaffolds for easy access to diverse glycohybrids and well-defined glycoconjugates for complete chemical, biochemical, and pharmacological investigations. This review highlights the successful development of CuAAC or click chemistry in emerging areas of glycoscience, including the synthesis of triazole appended carbohydrate-containing molecular architectures (mainly glycohybrids, glycoconjugates, glycopolymers, glycopeptides, glycoproteins, glycolipids, glycoclusters, and glycodendrimers through regioselective triazole forming modular and bio-orthogonal coupling protocols). It discusses the widespread applications of these glycoproducts as enzyme inhibitors in drug discovery and development, sensing, gelation, chelation, glycosylation, and catalysis. This review also covers the impact of click chemistry and provides future perspectives on its role in various emerging disciplines of science and technology.

Antioxidant and anti-sickling activity of glucal-based triazoles compounds - An in vitro and in silico study

The sickle cell disease (SCD) has a genetic cause, characterized by a replacement of glutamic acid to valine in the β-chain of hemoglobin. The disease has no effective treatment so far, and patients suffer a range from acute to chronic complications that include chronic hemolytic anemia, vaso-occlusive ischemia, pain, acute thoracic syndrome, cerebrovascular accident, nephropathy, osteonecrosis and reduced lifetime. The oxidation in certain regions of the hemoglobin favors the reactive oxygen species (ROS) formation, which is the cause of many clinical manifestations. Antioxidants have been studied to reduce the hemoglobin ROS levels, and in this sense, we have searched for new antioxidants glucal-based triazoles compounds with anti-sickling activity. Thirty analogues were synthetized and tested in in vitro antioxidant assays. Two of them were selected based in their effects and concentration-response activity and conducted to in cell assays. Both molecules did not cause any hemolysis and could reduce the red blood cell damage caused by hydrogen peroxide, in a model of oxidative stress induction that mimics the SCD. Moreover, one molecule (termed 11m), besides reducing the hemolysis, was able to prevent the cell damage caused by the hydrogen peroxide. Later on, by in silico pharmacokinetics analysis, we could see that 11m has appropriated proprieties for druggability and the probable mechanism of action is the binding to Peroxiredoxin-5, an antioxidant enzyme that reduces the hydrogen peroxide levels, verified after molecular docking assays. Thus, starting from 30 glucal-based triazoles molecules in a structure-activity relationship, we could select one with antioxidant proprieties that could act on RBC to reduce the oxidative stress, being useful for the treatment of SCD.

Synthesis of d-glyco-alkynone derivatives via carbonylative Sonogashira reaction

A carbonylative Sonogashira coupling approach to the synthesis of glyco-alkynones is described. Eighteen examples were obtained in moderate do nearly quantitative yields under mild conditions employing Mo(CO)6 as a safe carbon monoxide source. Functionalization of the alkynyl moiety via cycloaddition with organic azides provided six examples of glyco-triazoles.

The potential of click reactions for the synthesis of bioactive triterpenes

Click reactions between alkynes and azides using the privileged scaffold of triterpenes have been of interest for biological chemistry. Many publications deal with the synthesis of novel bioactive molecules; these conjugates have also been used for bioanalytical and diagnostic purposes. As a result, conjugates of better physicochemical properties were obtained; even compounds of improved solubility in water and physiological fluids were made through the introduction of a triazol residue. "Hybrid-structures", i.e. molecules consisting of two independently bioactive subunits linked by a triazole residue were higher bioactive than their parent compounds but not as active as expected, and with a few exceptions the ultimate breakthrough has not yet been achieved. Only in the synthesis of compounds with anti-leishmanial activity some new and promising lead structures were found. As a consequence, triazole modified triterpenes seem to hold their greatest future prospect rather as diagnostic reagents and molecular probes than as drugs.

Ultrasound-promoted organocatalytic enamine-azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

The use of sonochemistry is described in the organocatalytic enamine-azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones in good to excellent yields and short reaction times. In addition, this protocol was extended to β-keto esters, β-keto amides and α-cyano ketones. Selanyltriazoyl carboxylates, carboxamides and carbonitriles were synthesized in high yields at short times of reaction under very mild reaction conditions.

C-Glycopyranosyl Arenes and Hetarenes: Synthetic Methods and Bioactivity Focused on Antidiabetic Potential

This Review summarizes close to 500 primary publications and surveys published since 2000 about the syntheses and diverse bioactivities of C-glycopyranosyl (het)arenes. A classification of the preparative routes to these synthetic targets according to methodologies and compound categories is provided. Several of these compounds, regardless of their natural or synthetic origin, display antidiabetic properties due to enzyme inhibition (glycogen phosphorylase, protein tyrosine phosphatase 1B) or by inhibiting renal sodium-dependent glucose cotransporter 2 (SGLT2). The latter class of synthetic inhibitors, very recently approved as antihyperglycemic drugs, opens new perspectives in the pharmacological treatment of type 2 diabetes. Various compounds with the C-glycopyranosyl (het)arene motif were subjected to biological studies displaying among others antioxidant, antiviral, antibiotic, antiadhesive, cytotoxic, and glycoenzyme inhibitory effects.

Sonochemistry in organocatalytic enamine-azide [3+2] cycloadditions: A rapid alternative for the synthesis of 1,2,3-triazoyl carboxamides

We described herein the use of sonochemistry in the organocatalytic enamine-azide [3+2] cycloadditions of β-oxo-amides with a range of substituted aryl azides. These sonochemical promoted reactions were found to be amenable to a range of β-oxo amides or aryl azides, providing an efficient access to new N-aryl-1,2,3-triazoyl carboxamides in good to excellent yields and short times of reaction.

Cu-Catalyzed Click Reaction in Carbohydrate Chemistry

Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC), popularly known as the "click reaction", serves as the most potent and highly dependable tool for facile construction of simple to complex architectures at the molecular level. Click-knitted threads of two exclusively different molecular entities have created some really interesting structures for more than 15 years with a broad spectrum of applicability, including in the fascinating fields of synthetic chemistry, medicinal science, biochemistry, pharmacology, material science, and catalysis. The unique properties of the carbohydrate moiety and the advantages of highly chemo- and regioselective click chemistry, such as mild reaction conditions, efficient performance with a wide range of solvents, and compatibility with different functionalities, together produce miraculous neoglycoconjugates and neoglycopolymers with various synthetic, biological, and pharmaceutical applications. In this review we highlight the successful advancement of Cu(I)-catalyzed click chemistry in glycoscience and its applications as well as future scope in different streams of applied sciences.

Phenylselanyl-1H-1,2,3-triazole-4-carbonitriles: synthesis, antioxidant properties and use as precursors to highly functionalized tetrazoles

We describe herein our results on the synthesis, antioxidant properties and chemical diversification of phenylselanyl-1H-1,2,3-triazole-4-carbonitriles.

One-pot synthesis of 1-arylmethyl-4-[(E)-alk-1-enyl]-1H-1,2,3-triazoles via a cross-coupling/click reaction sequence

1-Arylmethyl-4-[(E)-alk-1-enyl]-1H-1,2,3-triazoles have been synthesized from terminal conjugated (E)-enynes, prepared by copper-mediated cross-coupling reaction of (E)-alk-1-enyldisiamylboranes with (trimethylsilyl)ethynyl bromide, benzyl bromides and sodium azide in a one-pot fashion.

Preparation of azidoaryl- and azidoalkyloxazoles for click chemistry

A series of azidoaryl- and azidoalkyl(diphenyl)oxazole scaffolds were warranted for biofilm inhibition studies. Cyclization of azidoaryl- or azidoalkyl esters of benzoin with ammonium acetate in acetic acid gives 2-azidoaryl- or 2-azidoalkyl-4,5-diphenyloxazoles. The azidoaryl esters are prepared from the corresponding azidocarboxylic acids/acid chlorides while the azidoalkyl esters are prepared from the corresponding haloalkyl esters.