A simple procedure to obtain 1,5-disubstituted 1,2,3-triazoles, using the catalytic system erbium(III) trifluoromethanesulfonate, 1-methyl pyridinium trifluoromethanesulfonate and water is described. The reaction proceeds through an eliminative azide–olefin cycloaddition (EAOC) offering a highly regioselective approach and good yields (81–94%). The advantages of this method include simple operations of work-up and the ability of the catalytic system to be re-used five times without an evident loss in yield.

The 1,2,3-triazole derivative 2-(4-chlorophenyl)-5-(pyrrolidin-1-yl)-2H-1,2,3-triazole-4-carboxylic acid with potential anticancer activity was used as a ligand in complex formation with the lan-thanum(III) ion. The molecular structure and vibrational spectra of the complex were optimized at three DFT levels and the scaled IR and Raman spectra were compared to the experimental ones. Several scaling procedures were used. Through a detailed analysis, the structure predicted for the newly synthetized La(III) complex was confirmed by the good accordance of the calculat-ed-experimental IR and Raman spectra. The best DFT method appears to be M06-2X with the Lanl2mb basis set, followed closely by Lanl2dz. The effect of the lanthanide atom on the molecular structure and atomic charge distribution of the triazole ring was evaluated. Potential free radical scavenging activity of both, ligand and complex, was investigated in several radical-generating model systems. Potential mechanisms of antioxidant action (hydrogen atom transfer – HAT and single electron transfer - SET) were elucidated.

A new sustainable heterogenous catalyst for copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC) was investigated. The preparation of the sustainable catalyst was carried out through the complexation reaction between the polysaccharide cellulose acetate backbone (CA) and copper(II) ions. The resulting complex [Cu(II)-CA] was fully characterized by using different spectroscopic methods such as FTIR, SEM, EDX, UV-Vis, and ICP analyses. The Cu(II)-CA complex exhibits a high activity in the CuAAC reaction for substituted alkynes and organic azides, leading to a selective synthesis of the corresponding 1,4-isomer 1,2,3-triazoles in water as solvent and working at room temperature. It is worth noting that this catalyst has several advantages from the sustainable chemistry point of view including no use of additives, biopolymer support, reactions carried out in water at room temperature, and easy recovery of the catalyst. These characteristics make it a potential candidate not only for the CuAAC reaction but also for other catalytic organic reactions.

Glycerol is a subproduct of biodiesel production and represents an important problem when generated in large scale. Alternatives that can utilize this unrefined byproduct is of potential interest. It is herein described the synthesis of a series of 1,2,3-triazoles using glycerol as starting material. The key step involved in the preparation of triazolic derivatives corresponded to the Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC), also known as click reaction, between 4-(azidomethyl)-2,2-dimethyl-1,3-dioxolane (3) and different terminal alkynes. The eight prepared derivatives were evaluated with regard to their fungicide, phytotoxic and cytotoxic activities. The fungicide activity was assessed in vitro against Colletotrichum gloeosporioides, the causing agent of papaya anthracnose. It was found that the compounds 1-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)cyclohexanol (4g) and 2-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)propan-2-ol (4h) demonstrated high efficiency on controlling C. gloeosporioides when compared to the commercial fungicide tebuconazole. The triazoles did not present any phytotoxic effect when evaluated against Lactuca sativa. However, five derivatives were mitodepressive, inducing cell death detected by the presence of condensed nuclei and acted as aneugenic agents in the cell cycle of L. sativa. It is believed that glycerol derivatives bearing 1,2,3-triazole functionalities may represent a scaffold to be explored toward the development of new agents to control C. gloeosporioides.

Four models of Ce(III) complexes with four ligands based on a 1,2,3-triazole derivatives were studied at four DFT levels. The effect of different ligands on the atomic charge value on the cerium ion was analyzed. Several relationships were clearly established between this atomic charge and that of the surrounding atoms, as well as with several geometric parameters of the ligand and with the molecular properties of the Ce(III) complex. The experimental IR and Raman spectra of the newly obtained Ce(III) complex with the (pyrrolidin-1-yl)-2H-1,2,3-triazole-4-carboxylate ligand were interpreted based on their comparison to the theoretical scaled ones using the scaling equations determined by two procedures and four DFT levels. Therefore, the structure predicted for the synthesized Ce(III) complex was clearly characterized and confirmed. The potential antioxidant action of Ce(III) complex was elucidated and compared with other Ln(III) complexes in order to find out the differences in their biological activity profiles.

The molecular structure and vibrational spectra of six 1,2,3-triazoles-containing molecules with possible anticancer activity were investigated. In two of them, the optimized geometry was determined in the monomer, cyclic dimer and staking forms using the B3LYP, M06-2X and MP2 methods. The effect of the para-substitution in the aryl ring was evaluated based on the changes in the molecular structure and atomic charge distribution of the triazole ring. Several relationships were obtained that could facilitate the selection of the substituents on the triazole ring for their further synthesis. The observed IR and Raman bands in the solid state of two of these compounds were accurately assigned according to the functional calculations on the monomer and dimer forms, together with the polynomic scaling equation procedure (PSE).

Wheat is one of the global strategic crops and ranks third in terms of cereals production. Wheat crop is exposed to many fungal infections during the cultivation stages, some of which have the ability to secrete numbers of toxic secondary metabolites that threaten the quality of grains, consumer health, producer economics and global trade exchange. Fifty-four random samples were collected from wheat which originated from different countries. The samples included 14 of soft wheat to study the extent of their contamination with Deoxynivalenol (DON) and T-2 toxin by auto-ELISA technology and r-biopharm Microtiter plate. All samples were contaminated with DON toxin except one sample, and the contamination average ranged between 40.7 and 1018.8 µg kg-1. The highest contamination rates were in Lithuanian and the lowest in Indian wheat. Meanwhile the highest average level of T-2 toxin contamination was in Lithuanian wheat grains with a rate of 377.4µg kg-1 and the lowest in Polish wheat with an average of 115.3µg kg-1. GC-MS/MS and multiple reaction monitoring mode (MRM), was used to detect 15 triazole derivatives in collected samples, which may be used to combat fungal diseases on wheat during the growing season. Only 9 derivatives were found; Simeconazole, Penconazole, Hexaconazole, Cyproconazole, Diniconazole, Tebuconazole, Metconazole, Fenbuconazole and Difenoconazole. These derivatives varied according to the origin of wheat samples as well as their its concentration whereas, another 6 derivatives were not detected in all samples. A direct inverse relationship was found between the DON concentration in the samples and the residues of Simeconazole, Penconazole, Diniconazole, Tebuconazole, Metconazole, Fenbuconazole and Difenoconazole and the T-2 toxin showed the same relationship except for Tebuconazole. The safe and rational use of some triazole derivatives may be a new approach and a promising strategy not only to reduce plant diseases and their problems, but also to get rid of some mycotoxins as contaminates.

An efficient, eco-compatible and very cheap method for the construction of triazoles via eliminative azide–olefin cycloaddition (EAOC) reaction has been developed by a catalytic system IL/FeCl3, offering an highly regioselective approach to structurally diverse 1,5-disubstituted 1,2,3-triazoles in up to 95% yield. This strategy features the reuse of catalytic system through simple operations. Mechanistic studies indicated that an asynchronous concerted dipolar cycloaddition-elimination process might be involved.

We hereby describe an efficient method for the preparation of a series of new 1-substituted 1,2,3-triazole-based acetaminophen derivatives through a clean, good-yielding, simple, and expeditious procedure based on the O-propargylation reaction of the acetaminophen (APAP) obtained from expired commercial tablets and the CuBr(PPh3)3-catalyzed Huisgen reaction be-tween O-propargylated APAP and diverse organoazides prepared from commercially available anilines as available starting reagents. An interesting nitric oxide-releasing 1,2,3-triazole hybrid of APAP was also obtained easily using the developed method. The structures of the designed hybrid compounds, which are expected to be pharmacologically active, were fully characterized by FT-IR, 1H- and 13C-NMR and are reported for the first time. According to the in-silico studies performed in this work and literature analysis, these hybrids are interesting models in search of new pharmacological nontoxic agents endowed with anti-inflammatory and anticancer properties.