Recent accomplishments on the synthetic/biological facets of pharmacologically active 1H-1,2,3-triazoles

Comprehensive Review on the Synthesis of [1,2,3]Triazolo[1,5-a]Quinolines

This report outlines the evolution and recent progress about the different protocols to synthesize the N-heterocycles fused hybrids, specifically [1,2,3]triazolo[1,5-a]quinoline. This review encompasses a broad range of approaches, describing several reactions for obtaining this since, such as dehydrogenative cyclization, oxidative N-N coupling, Dieckmann condensation, intramolecular Heck, (3+2)-cycloaddition, Ullman-type coupling and direct intramolecular arylation reactions. We divided this review in three section based in the starting materials to synthesize the target [1,2,3]triazolo[1,5-a]quinolines. Starting materials containing quinoline or triazole units previously formed, as well as starting materials which both quinoline and triazole units are formed in situ. Different methods of obtaining are described, such as metal-free or catalyzed conditions, azide-free, using conventional heating or alternative energy sources, such as electrochemical and photochemical methods. Mechanistic insights underlying the reported reactions were also described in this comprehensive review.

Novel benzenesulfonamides containing a dual triazole moiety with selective carbonic anhydrase inhibition and anticancer activity

A series of sulfonamides incorporating a 1,2,3-triazolyloxime substituted 1,2,3-triazolyl moiety were conceptualized and synthesized as human carbonic anhydrase (hCA) inhibitors. The synthesized small structures, denoted 7a through 7o, exhibited moderate inhibitory effects against the tumor-associated isoforms hCA IX and hCA XII compared to the well-known hCA inhibitor acetazolamide. In contrast, these molecules demonstrated higher potency and a diverse range of selectivity against the cytosolic isoforms hCA I and hCA II. Notably, the 4-hydroxyphenyl derivative (compound 7dversus cytosolic isoforms), the 4-acetylphenyl derivative (compound 7o), and the phenyl derivative (compound 7a) emerged as the most potent and selective inhibitors in this series, with inhibition constants (K I) of 47.1, 35.9, 170.0, and 149.9 nM, respectively, against hCA I, II, IX, and XII. Further cytotoxicity assays of compounds 7a-o against cancer cell lines Hep3B and A549, as well as normal cell line L929, were conducted to assess their selectivity towards malignant cells. Compounds 7d, 7g, and 7k exhibited selective cytotoxicity towards the Hep3B cell line, with reduced selectivity towards A549, whereas compound 7j demonstrated higher selectivity for the A549 cell line. Additionally, molecular docking studies were performed to elucidate the binding modes of these compounds within the active sites of hCAs, revealing crucial interactions that underpin their significant activity and selectivity for the tumor-specific isoforms.

Click-chemistry-inspired synthesis of new series of 1,2,3-triazole fused chromene with glucose triazole conjugates: Antibacterial activity assessment with molecular docking evaluation

A series of new 1,2,3-triazole fused chromene based glucose triazole conjugates were synthesized from chromene fused 1,2,3-triazolyl extended alkyne and 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl azide in good to excellent yield by a copper catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The major advantages include mild reaction conditions, high yield, good substrate scope, and shorter reaction time. The antibacterial efficacy of the compounds were assessed in vitro against human pathogenic Gram-negative E. coli and Gram-positive S. aureus bacteria. Compound 24j was found to be the most potent molecule with zone of inhibition (ZI) of 17 mm and minimum inhibitory concentration (MIC) of 25 μg mL-1 in E. coli and ZI of 16 mm and MIC of 25 μg mL-1 in S. aureus. Also, it significantly inhibited E. coli DNA-gyrase in silico with a binding affinity of -9.4 kcal/mol. Among all the synthesized compounds, 24i, 24d, 24e and 24f showed significant antibacterial activity against both strains and inhibited DNA-gyrase in silico with good binding affinities. Hence, these 1,2,3-triazole fused chromene based glucose triazole conjugates may evolve to be powerful antibacterial agents in recent future, according to structure-activity relationships based on strong antibacterial properties and molecular docking studies.

New thymol-derived triazole exhibits promising activity against Trichophyton rubrum

Fungal infections have emerged worldwide, and azole antifungals are widely used to control these infections. However, the emergence of antifungal resistance has been compromising the effectiveness of these drugs. Therefore, the objective of this study was to evaluate the antifungal and cytotoxic activities of the nine new 1,2,3 triazole compounds derived from thymol that were synthesized through Click chemistry. The binding mode prediction was carried out by docking studies using the crystallographic structure of Lanosterol 14α-demethylase G73E mutant from Saccharomyces cerevisiae. The new compounds showed potent antifungal activity against Trichophyton rubrum but did not show relevant action against Aspergillus fumigatus and Candida albicans. For T. rubrum, molecules nº 5 and 8 showed promising results, emphasizing nº 8, whose fungicidal and fungistatic effects were similar to fluconazole. In addition, molecule nº 8 showed low toxicity for keratinocytes and fibroblasts, concluding that this compound demonstrates promising characteristics for developing a new drug for dermatophytosis caused by T. rubrum, or serves as a structural basis for further research.

Coumarin linked thiazole derivatives as potential α-glucosidase inhibitors to treat diabetes mellitus

Diabetes is a leading cause of kidney failure, blindness, heart attacks and lower limb amputation. Prevalence of diabetes is rising globally. α-glucosidase is validated target for controlling hyperglycemia because of its role in catalysing hydrolysis of carbohydrates to glucose in GIT. In an attempt to find novel safe and effective α-glucosidase inhibitors, coumarin linked thiazole was identified as potential scaffold on the basis of its interactions with the active site of α-glucosidase studied in silico. A series of coumarin linked thiazole derivatives were synthesized and analyzed for α-glucosidase inhibitory potential in an in-vitro assay. The synthesized molecules showed potent inhibition of α-glucosidase with IC50 values ranging from 0.14 to 9.38 μM. The most potent compound 2-[(4-bromophenyl) amino)-N-(4- (2-oxo-2H-chromen-3-yl) thiazol-2-yl] acetamide was further docked with α-glucosidase and molecular dynamics studies were carried out for 100 ns which suggested the stability of protein and ligand in the protein active site over the simulation period and role of hydrophobic interactions slightly more than the electrostatic/polar interactions in ligand- receptor stability. In summary, our results demonstrate efficacy of coumarin-linked thiazole as potential leads for further optimization and development.

Design, synthesis and molecular docking study of novel triazole-quinazolinone hybrids as antimalarial and antitubercular agents

In a quest to discover new antimalarial and antitubercular drugs, we have designed and synthesized a series of novel triazole-quinazolinone hybrids. The in vitro screening of the triazole-quinazolinone hybrid entities against the plasmodium species P. falciparum offered potent antimalarial molecules 6c, 6d, 6f, 6g, 6j & 6k owing comparable activity to the reference drugs. Furthermore, the target compounds were evaluated in vitro against Mycobacterium tuberculosis (MTB) H37Rv strain. Among the screened compounds, 6c, 6d and 6l were found to be the most active molecules with a MIC values of 19.57-40.68 μM. The cytotoxicity of the most active compounds was studied against RAW 264.7 cell line by MTT assay and no toxicity was observed. The computational study including drug likeness and ADMET profiling, DFT, and molecular docking study was done to explore the features of target molecules. The compounds 6a, 6g, and 6k exhibited highest binding affinity of -10.3 kcal/mol with docked molecular targets from M. tuberculosis. Molecular docking study indicates that all the molecules are binding to the falcipain 2 protease (PDB: 6SSZ) of the P. falciparum. Our findings indicated that these new triazole-quinazolinone hybrids may be considered hit molecules for further optimization studies.

The anti-breast cancer therapeutic potential of 1,2,3-triazole-containing hybrids

Breast cancer, as one of the most common invasive malignancies and the leading cause of cancer-related deaths in women globally, poses a significant challenge in the world health system. Substantial advances in diagnosis and treatment have significantly improved the survival rate of breast cancer patients, but the number of incidences and deaths of breast cancer are projected to increase by 40% and 50%, respectively, by 2040. Chemotherapy is one of the principal treatments for breast cancer therapy, but multidrug resistance and severe side effects remain the major obstacles to the success of treatment. Hence, there is a vital need to develop novel chemotherapeutic agents to combat this deadly disease. 1,2,3-Triazole, which can be effectively constructed by click chemistry, not only can serve as a linker to connect different anti-breast cancer pharmacophores but also is a valuable pharmacophore with anti-breast cancer potential and favorable properties such as hydrogen bonding, moderate dipole moment, and enhanced water solubility. Particularly, 1,2,3-triazole-containing hybrids have demonstrated promising in vitro and in vivo anti-breast cancer potential against both drug-sensitive and drug-resistant forms and possessed excellent selectivity by targeting different biological pathways associated with breast cancer, representing privileged scaffolds for the discovery of novel anti-breast cancer candidates. This review concentrates on the latest advancements of 1,2,3-triazole-containing hybrids with anti-breast cancer potential, including work published between 2020 and the present. The structure-activity relationships (SARs) and mechanisms of action are also reviewed to shed light on the development of more effective and multitargeted candidates.

Unveiling the anticancer mechanism of 1,2,3-triazole-incorporated thiazole-pyrimidine-isoxazoles: insights from docking and molecular dynamics simulations

Cancer is a major global health concern, and the constant search for novel, selective anticancer compounds with low toxicity is never ending. Nitrogen heterocyclic compounds such as pyrimidine and triazole have been identified as potential candidates for cancer treatment. A novel series of 1,2,3-triazole incorporated thiazole-pyrimidine-isoxazole derivatives 10 (a-j) were designed, synthesized and evaluated for antitumorigenic activities against human breast cancer (MCF-7), human lung cancer (A549) and human prostate (PC3 & DU-145) various cell-lines by employing MTT assay using etoposide as the positive control. The synthesized hybrids yielded decent efficacy, which was further compared with the standard drug. Among all the molecules, 10h revealed the more potent anticancerous activities, having IC50 values ranging from 0.011 ± 0.0017 µM; 0.063 ± 0.0012 µM; 0.017 ± 0.0094 µM and 0.66 ± 0.072 µM with DU145, PC3, A549, and MCF7 cell-lines, respectively. Tubulin, being a major protein involved with diverse biological actions, also serves, as a crucial target for several clinically practiced anticancer drugs, was utilized for docking analyses to evaluate the binding affinity of ligands. Docking results demonstrates that the selected hybrids 10 (g-j) exhibited good binding affinities with protein. Subsequently, drug likeness studies were carried out on the synthesized compounds to evaluate and analyze their drug like properties such as absorption, distribution, metabolism, excretion, and toxicity (ADMET) for toxicity prediction. Based on these analyses, the selected complexes were further employed for molecular dynamic simulations to analyze stability via an exhaustive cumulative 200 nanoseconds simulation. These results suggest that the selected compounds are stable and might serve as potential inhibitors to tubulin complex. In conclusion, we propose these synthesized compounds 10 (g-j) might provide new insights into cancer treatment and have potential for future development.Communicated by Ramaswamy H. Sarma.

NH-1,2,3-triazoles as versatile building blocks in denitrogenative transformations

The utilization of NH-1,2,3-triazoles as easily accessible building blocks in denitrogenative ring cleavage transformations with electrophiles to provide multifunctionalized nitrogen heterocycles and N-alkenyl compounds is reviewed. Leveraging the ready availability of NH-1,2,3-triazoles, these processes provide a convenient route to a range of pharmaceutically relevant heterocyclic cores and N-alkenyl compounds. The synthetic usefulness of in situ acylated NH-1,2,3-triazoles as viable alternatives to widely explored N-sulfonyl-1,2,3-triazoles in ring cleavage processes is highlighted.

Proliferation, Migration and Invasion of Breast Cancer Cell Lines Are Inhibited by 1,5-Disubstituted Tetrazol-1,2,3-triazole Hybrids through Interaction with p53

The anticarcinogenic potential of a series of 1,5-disubstituted tetrazole-1,2,3-triazole hybrids (T-THs) was evaluated in the breast cancer (BC)-derived cell lines MCF-7 (ER+, PR+, and HER2-), CAMA-1 (ER+, PR+/-, and HER2-), SKBR-3 (ER+, PR+, and HER2+), and HCC1954 (ER+, PR+, and HER2+). The T-THs 7f, 7l, and 7g inhibited the proliferation of MCF-7 and CAMA-1, HCC1954, and SKBR-3 cells, respectively. The compounds with stronger effect in terms of migration and invasion inhibition were 7o, 7b, 7n, and 7k for the CAMA-1, MCF-7, HCC1954, and SKBR-3 cells respectively. Interestingly, these T-THs were the compounds with a fluorine present in their structures. To discover a possible target protein, a molecular docking analysis was performed for p53, p38, p58, and JNK1. The T-THs presented a higher affinity for p53, followed by JNK1, p58, and lastly p38. The best-predicted affinity for p53 showed interactions between the T-THs and both the DNA fragment and the protein. These results provide an opportunity for these compounds to be studied as potential drug candidates for breast cancer treatment.

Understanding the Fate of the Banert Cascade of Propargylic Azides: Sigmatropic versus Prototropic Pathway

The Banert cascade is an efficient synthetic strategy for obtaining 4,5-disubstituted 1,2,3-triazoles. The reaction can proceed via a sigmatropic or prototropic mechanism depending on the substrate and the conditions. In this work, the mechanisms of both pathways from propargylic azides with different electronic features were investigated using density functional theory, quantum theory of atoms in molecules, and natural bond orbital approaches. The calculated energy barriers were consistent with the experimental data. Three patterns of electron density distribution on the transition structures were observed, which reflected the behaviors of the reactants in the Banert cascade. The stronger conjugative effects were associated with lower/higher free activation energies of sigmatropic/prototropic reactions, respectively. A clear relationship between the accumulation of the charge at the C³ atom of propargylic azides with the energy barriers for prototropic reactions was found. Thus, the obtained results would allow the prediction of the reaction's course by evaluating reactants.

Multistep Synthesis of Analogues of Remdesivir: Incorporating Heterocycles at the C-1' Position

Studies suggest that the 1'β-CN moiety in remdesivir sterically clashes with the Ser861 residue of the RNA-dependent-RNA polymerase (RdRp), causing a delayed chain termination in the RNA replication process. Replacing C1'β-CN with 5-membered heterocycles such as tetrazoles, oxadiazoles, and triazoles can augment the inhibitory activity and pharmacokinetic profile of C-nucleotides. Synthesis of tetrazole-, triazole-, and oxadiazole-integrated C1' analogues of remdesivir was attempted using general synthetic routes. The final compounds 26, 28, and 29 did not inhibit viral replication; however, the synthetic intermediates, i.e., 27 and 50, exhibited an IC90 = 14.1 μM each. The trifluoromethyl-substituted 1,2,4-oxadiazole 59 showed an IC90 of 33.5 μM. This work adds to the growing evidence of the beneficial medicinal impact of C1,1'-disubstituted C-nucleotides.

Recent updates on 1,2,3-triazole-containing hybrids with in vivo therapeutic potential against cancers: A mini-review

1,2,3-Triazole moiety which is usually constructed by highly versatile, efficacious and selective copper-catalyzed azide-alkyne cycloaddition not only can act as a linker to connect different pharmacophores, but also is a useful pharmacophore with diverse biological properties. 1,2,3-Triazoles are readily interact with diverse enzymes and receptors in cancer cells through non-covalent interactions and can inhibit cancer cell proliferation, arrest cell cycle and induce apoptosis. In particular, 1,2,3-triazole-containing hybrids have the potential to exert dual or multiple anticancer mechanisms of action, representing useful scaffolds in expediting development of novel anticancer agents. The current review summarizes the in vivo anticancer efficacy and mechanisms of action of 1,2,3-triazole-containing hybrids reported in the last decade to continuously open up a map for the remarkable exploration of more effective candidates.

Discovery of new 1,4-disubstituted 1,2,3-triazoles: in silico ADME profiling, molecular docking and biological evaluation studies

In this work, eight new 1,2,3-triazoles (6a-h) were synthesized from acetylenes' "click" reaction with p-substituted azide derivatives. The structures of the compounds were characterized using standard analytical and spectroscopic methods (elemental analysis, FT-IR, ¹H(¹³C)NMR). The anticancer, antioxidant, α-amylase, ADME, molecular docking studies of synthesized triazoles were investigated. According to α -amylase enzyme inhibition results, all compounds except 6c (IC₅₀: 2299 μg/mL) were found to have a higher IC₅₀ value than the standard drug acarbose (IC₅₀: 891 μg/mL). Compound 6g (IC₅₀: 68 μg/mL) exhibited 13 times higher activity than standard acarbose. All compounds, except 6e, have been shown to have greater DPPH radical scavenging capabilities than BHT and β-carotene standards. According to ABTS radical scavenging studies, all compounds showed higher scavenging activity than ascorbic acid and Trolox. To determine the anticancer activity of the synthesized compounds, they were screened against the Hela cell line, and the results were compared with standard cisplatin (IC₅₀: 16.30 μg/mL). Compound 6a (IC₅₀: 49.03 μg/mL) was determined to have moderate activity relative to cisplatin. The compounds were examined comprehensively for ADME characteristics and did not violate any drug-likeness rule. ADME data showed that all physicochemical and pharmacological parameters of the compounds remained within defined limits as specified in Lipinski's rules (RO5) and put forth a high bioavailability profile. The molecular docking findings show that all molecules have a high affinity by exhibiting polar and apolar contact with essential residues in the binding pocket of α-amylase.Communicated by Ramaswamy H. Sarma.

Synthesis and in vitro antileishmanial activity of alkylene-linked nitrofurantoin-triazole hybrids

Leishmaniasis is a vector-borne parasitic disease that mostly affects populations in tropical and sub-tropical countries. There is currently no protective anti-leishmanial vaccine and only a paucity of clinical drugs is available to treat this disease albeit their toxicity. Leishmaniasis is curable but its eradication and elimination have been hampered by the emergence of multidrug resistant strains of the causative pathogens. This heightens the necessity for new and effective antileishmanial drugs. In search for such agents, nitrofurantoin, a clinical antibiotic, was appended to triazole scaffold through alkylene linkers of various length, and the resulting hybrids were evaluated for in vitro antileishmanial efficacy against Leishmania (L.) parasite of two strains. The hybrid 13, harboring a n-pentylene linker was uncovered as a leishmanicidal hit with micromolar activity against antimonial-resistant L. donovani, the causative of deadly visceral Leishmaniasis.

3-(1,2,3-Triazol-4-yl)-β-Carbolines and 3-(1H-Tetrazol-5-yl)-β-Carbolines: Synthesis and Evaluation as Anticancer Agents

Herein, the synthesis and anticancer activity evaluation of a series of novel β-carbolines is reported. The reactivity of nitrosoalkenes towards indole was explored for the synthesis of novel tryptophan analogs where the carboxylic acid was replaced by a triazole moiety. This tryptamine was used in the synthesis of 3-(1,2,3-triazol-4-yl)-β-carbolines via Pictet-Spengler condensation followed by an oxidative step. A library of compounds, including the novel 3-(1,2,3-triazol-4-yl)-β-carbolines as well as methyl β-carboline-3-carboxylate and 3-tetrazolyl-β-carboline derivatives, was evaluated for their antiproliferative activity against colorectal cancer cell lines. The 3-(1H-tetrazol-5-yl)-β-carbolines stood out as the most active compounds, with values of half-maximal inhibitory concentration (IC₅₀) ranging from 3.3 µM to 9.6 µM against colorectal adenocarcinoma HCT116 and HT29 cell lines. The results also revealed a mechanism of action independent of the p53 pathway. Further studies with the 3-tetrazolyl-β-carboline derivative, which showed high selectivity for cancer cells, revealed IC₅₀ values below 8 μM against pancreatic adenocarcinoma PANC-1, melanoma A375, hepatocarcinoma HEPG2, and breast adenocarcinoma MCF-7 cell lines. Collectively, this work discloses the 3-tetrazolyl-β-carboline derivative as a promising anticancer agent worthy of being further explored in future works.

Synthesis and biological activity profile of novel triazole/quinoline hybrids

Based on the significant and diverse pharmacophore features of triazole ring and considering the potent antimicrobial properties of quinoline scaffold, a novel series of 1,2,3-triazole-based polyaromatic compounds containing chloroquinoline moiety were synthesized through a well-established synthetic methodology, named click chemistry. The structure of the synthetic compounds was characterized by various spectroscopic methods. The final products of triazole/quinoline hybrids and ((prop-2-yn-1-yloxy)methyl)benzene intermediates were screened for their antibacterial (Staphylococcus aureus, Escherichia coli, Shigella flexneri, and Salmonella enterica), antifungal (Candida albicans, Saccharomyces cerevisiae, and Aspergillus fumigatus), and cytotoxic activities. The best antifungal compounds exhibited minimum inhibitory concentration (MIC), in the range of 0.35-0.63 µM, against S. cerevisiae without any cytotoxic effect. These compounds can be selected as the potential candidates for treating invasive fungal infections caused by S. cerevisiae, after further investigation. Preliminary in silico ADME studies also predicted the favorable pharmacokinetic attributes of most compounds.

A minireview of 1,2,3-triazole hybrids with O-heterocycles as leads in medicinal chemistry

Over the past few decades, the dynamic progress in the synthesis and screening of heterocyclic compounds against various targets has made a significant contribution in the field of medicinal chemistry. Among the wide array of heterocyclic compounds, triazole moiety has attracted the attention of researchers owing to its vast therapeutic potential and easy preparation via copper and ruthenium-catalyzed azide-alkyne cycloaddition reactions. Triazole skeletons are found as major structural components in a different class of drugs possessing diverse pharmacological profiles including anti-cancer, anti-bacterial, anti-fungal, anti-viral, anti-oxidant, anti-inflammatory, anti-diabetic, anti-tubercular, and anti-depressant among various others. Furthermore, in the past few years, a significantly large number of triazole hybrids were synthesized with various heterocyclic moieties in order to gain the added advantage of the improved pharmacological profile, overcoming the multiple drug resistance and reduced toxicity from molecular hybridization. Among these synthesized triazole hybrids, many compounds are available commercially and used for treating different infections/disorders like tazobactam and cefatrizine as potent anti-bacterial agents while isavuconazole and ravuconazole as anti-fungal activities to name a few. In this review, we will summarize the biological activities of various 1,2,3-triazole hybrids with copious oxygen-containing heterocycles as lead compounds in medicinal chemistry. This review will be very helpful for researchers working in the field of molecular modeling, drug design and development, and medicinal chemistry.

The 1,2,3-triazole 'all-in-one' ring system in drug discovery: a good bioisostere, a good pharmacophore, a good linker, and a versatile synthetic tool

INTRODUCTION

The 1,2,3-triazole ring occupies an important space in medicinal chemistry due to its unique structural properties, synthetic versatility and pharmacological potential making it a critical scaffold. Since it is readily available through click chemistry for creating compound collections against various diseases, it has become an emerging area of interest for medicinal chemists.

AREAS COVERED

This review article addresses the unique properties of the1,2,3-triazole nucleus as an intriguing ring system in drug discovery while focusing on the most recent medicinal chemistry strategies exploited for the design and development of 1,2,3-triazole analogs as inhibitors of various biological targets.

EXPERT OPINION

Evidently, the 1,2,3-triazole ring with unique structural features has enormous potential in drug design against various diseases as a pharmacophore, a bioisoster or a structural platform. The most recent evidence indicates that it may be more emerging in drug molecules in near future along with an increasing understanding of its prominent roles in drug structures. The synthetic feasibility and versatility of triazole chemistry make it certainly ideal for creating compound libraries for more constructive structure-activity relationship studies. However, more comparative and target-specific studies are needed to gain a deeper understanding of the roles of the 1,2,3-triazole ring in molecular recognition.[Figure: see text].

α-Glucosidase and α-Amylase Inhibitory Potentials of Quinoline-1,3,4-oxadiazole Conjugates Bearing 1,2,3-Triazole with Antioxidant Activity, Kinetic Studies, and Computational Validation

Diabetes mellitus (DM) is a multifaceted metabolic disorder that remains a major threat to global health security. Sadly, the clinical relevance of available drugs is burdened with an upsurge in adverse effects; hence, inhibiting the carbohydrate-hydrolyzing enzymes α-glucosidase and α-amylase while preventing oxidative stress is deemed a practicable strategy for regulating postprandial glucose levels in DM patients. We report herein the α-glucosidase and α-amylase inhibition and antioxidant profile of quinoline hybrids 4a–t and 12a–t bearing 1,3,4-oxadiazole and 1,2,3-triazole cores, respectively. Overall, compound 4i with a bromopentyl sidechain exhibited the strongest α-glucosidase inhibition (IC₅₀ = 15.85 µM) relative to reference drug acarbose (IC₅₀ = 17.85 µM) and the best antioxidant profile in FRAP, DPPH, and NO scavenging assays. Compounds 4a and 12g also emerged as the most potent NO scavengers (IC₅₀ = 2.67 and 3.01 µM, respectively) compared to gallic acid (IC₅₀ = 728.68 µM), while notable α-glucosidase inhibition was observed for p-fluorobenzyl compound 4k (IC₅₀ = 23.69 µM) and phenyl-1,2,3-triazolyl compound 12k (IC₅₀ = 22.47 µM). Moreover, kinetic studies established the mode of α-glucosidase inhibition as non-competitive, thus classifying the quinoline hybrids as allosteric inhibitors. Molecular docking and molecular dynamics simulations then provided insights into the protein–ligand interaction profile and the stable complexation of promising hybrids at the allosteric site of α-glucosidase. These results showcase these compounds as worthy scaffolds for developing more potent α-glucosidase inhibitors with antioxidant activity for effective DM management.

Anti-Inflammatory Activity of 4-(4-(Heptyloxy)phenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one via Repression of MAPK/NF-κB Signaling Pathways in β-Amyloid-Induced Alzheimer's Disease Models

Alzheimer’s disease (AD) is a major neurodegenerative disease, but so far, it can only be treated symptomatically rather than changing the process of the disease. Recently, triazoles and their derivatives have been shown to have potential for the treatment of AD. In this study, the neuroprotective effects of 4-(4-(heptyloxy)phenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (W112) against β-amyloid (Aβ)-induced AD pathology and its possible mechanism were explored both in vitro and in vivo. The results showed that W112 exhibits a neuroprotective role against Aβ-induced cytotoxicity in PC12 cells and improves the learning and memory abilities of Aβ-induced AD-like rats. In addition, the assays of the protein expression revealed that W112 reversed tau hyperphosphorylation and reduced the production of proinflammatory cytokines, tumor necrosis factor-α and interleukin-6, both in vitro and in vivo studies. Further study indicated that the regulation of mitogen-activated protein kinase/nuclear factor-κB pathways played a key role in mediating the neuroprotective effects of W112 against AD-like pathology. W112 may become a potential drug for AD intervention.

Synthesis of novel immunomodulatory 1,4-disubstituted bis-1,2,3-triazoles by using click chemistry and their intracellular mechanism of action

In this study, six new 1,4-disubstituted bis-1,2,3-triazole compounds, N,N'-(1,2-phenylene)bis(2-(4-R-1H-1,2,3-triazol-1-yl)acetamide), were synthesized with high yield (88-96 %) by using click chemistry and their molecular structures were characterized by using NMR, FT-IR, HRMS and elemental analysis techniques. Previous studies suggest anti-inflammatory and analgesic activities for different 1,2,3-triazole derivatives and in the light of those studies we aimed to examine these novel derivatives immunomodulatory activities on the mammalian macrophages. Pro-inflammatory cytokines (TNF, IL6, GMCSF and IL12p40) secretion levels were tested in the presence of bis-1,2,3-triazole compounds when the macrophages were activated with LPS. These new derivatives were able to suppress the production of these cytokines at different levels. Intracellular phophorylated PI3K protein levels were measured due to its prominent role in inflammatory reactions. Our flow cytometry analysis results suggested that some of these compounds were partially effective through PI3K pathway. In different inflammatory and autoimmune disease settings these novel 1,2,3-triazole derivatives can be utilized as non-steroid based anti-inflammatory drug candidates.

Design, Synthesis and Molecular Docking of Novel Acetophenone-1,2,3-Triazoles Containing Compounds as Potent Enoyl-Acyl Carrier Protein Reductase (InhA) Inhibitors

New medications are desperately needed to combat rising drug resistance among tuberculosis (TB) patients. New agents should ideally work through unique targets to avoid being hampered by preexisting clinical resistance to existing treatments. The enoyl-acyl carrier protein reductase InhA of M. tuberculosis is one of the most crucial targets since it is a promising target that has undergone extensive research for anti-tuberculosis drug development. A well-known scaffold for a variety of biological activities, including antitubercular activity, is the molecular linkage of a1,2,3-triazole with an acetamide group. As a result, in the current study, which was aided by ligand-based molecular modeling investigations, 1,2,3-triazolesweredesigned and synthesized adopting the CuAAC aided cycloaddition of 1-(4-(prop-2-yn-1-yloxy)phenyl)ethanone with appropriate acetamide azides. Standard spectroscopic methods were used to characterize the newly synthesized compounds. In vitro testing of the proposed compounds against the InhA enzyme was performed. All the synthesized inhibitors completely inhibited the InhA enzyme at a concentration of 10 µM that exceeded Rifampicin in terms of activity. Compounds 9, 10, and 14 were the most promising InhA inhibitors, with IC₅₀ values of 0.005, 0.008, and 0.002 µM, respectively. To promote antitubercular action and investigate the binding manner of the screened compounds with the target InhA enzyme’s binding site, a molecular docking study was conducted.

Synthesis and Biological Evaluation of Small Molecules as Potential Anticancer Multitarget Agents

Twenty-six triazole-based derivatives were designed for targeting both PD-L1 (programmed death receptor ligand 1) and VEGFR-2 (vascular endothelial growth factor receptor 2). These compounds were synthetized and biologically evaluated as multitarget inhibitors of VEGFR-2, PD-L1 and c-Myc proteins. The antiproliferative activity of these molecules on several tumor cell lines (HT-29, A-549, and MCF-7) and on the non-tumor cell line HEK-293 was determined. The effects on the abovementioned biological targets were evaluated for some selected compounds. Compound 23, bearing a p-chlorophenyl group, showed better results than sorafenib in regard to the downregulation of VEGFR-2 and a similar effect to BMS-8 on both PD-L1 and c-Myc proteins. The antiangiogenic and antivascular activities of chloro derivatives were also established by endothelial microtube formation assay on Matrigel^®.

Synthesis, Spectroscopic Analysis, and In Vitro Anticancer Evaluation of 2-(Phenylsulfonyl)-2H-1,2,3-triazole

The 1,2,3-Triazole derivatives containing the sulfonyl group have proved their biological importance in medicinal chemistry and drug design. In this sense, we describe the regioselective synthesis of 2-(phenylsulfonyl)-2H-1,2,3-triazole 3 in good yield through a classical sulfonamidation reaction of 1H-1,2,3-triazole 1 with benzenesulfonyl chloride 2 in dichloromethane using a slight excess of triethylamine at 20 °C for 3 h. This procedure is distinguished by its short reaction time, high yield, excellent regioselectivity, clean reaction profile, and operational simplicity. The sulfonamide 3 was characterized by high-resolution mass spectrometry, FT–IR, UV–Vis, 1D and 2D NMR spectroscopy, and elemental analysis. The sulfonamide 3 exhibited moderate activity against UO-31 renal, SNB-75 central nervous system, HCT-116 colon, and BT-549 breast cancer cell lines, with growth inhibition percentages (GI%) ranging from 10.83% to 17.64%.

Emerging impact of triazoles as anti-tubercular agent

Tuberculosis, a disease of poverty is a communicable infection with a reasonably high mortality rate worldwide. 10 Million new cases of TB were reported with approx 1.4 million deaths in the year 2019. Due to the growing number of drug-sensitive and drug-resistant tuberculosis cases, there is a vital need to develop new and effective candidates useful to combat this deadly disease. Despite tremendous efforts to identify a mechanism-based novel antitubercular agent, only a few have entered into clinical trials in the last six decades. In recent years, triazoles have been well explored as the most valuable scaffolds in drug discovery and development. Triazole framework possesses favorable properties like hydrogen bonding, moderate dipole moment, enhanced water solubility, and also the ability to bind effectively with biomolecular targets of M. tuberculosis and therefore this scaffold displayed excellent potency against TB. This review is an endeavor to summarize an up-to-date innovation of triazole-appended hybrids during the last 10 years having potential in vitro and in vivo antitubercular activity with structure activity relationship analysis. This review may help medicinal chemists to explore the triazole scaffolds for the rational design of potent drug candidates having better efficacy, improved selectivity and minimal toxicity so that these hybrid NCEs can effectively be explored as potential lead to fight against M. tuberculosis.

Synthesis and Structural Characterization of a New 1,2,3-Triazole Derivative of Pentacyclic Triterpene

The new 30-substituted triazole derivative of 3,28-O,O′-diacetylbetulin was obtained in the copper(I) catalyzed azide-alkyne cycloaddition (CuAAC). The title compound was characterized by NMR, IR, HR-MS, and X-ray diffraction techniques. The X-ray diffraction study showed that the 1,2,3-triazole derivative crystallizes in the orthorhombic space group P212121, Z = 4, and unit cell parameters are as follows a = 9.4860(10) Å, b = 13.9440(2) Å, and c = 30.2347(4) Å. The molecular packing is stabilized by intermolecular hydrogen interactions C-H…O. The Hirshfeld surface analysis showed the presence of the O…H interactions with a percentage of the 16.5% in the total Hirshfeld area. The MEP analysis showed that the nucleophilic regions are located near the oxygen atoms of the acyl and carbonyl groups of betulin moiety and the sulfur atom in the triazole linker. The HOMO and LUMO orbitals are located near the triazole moiety. The obtained results indicated that this new betulin derivative is more reactive with electrophilic than nucleophilic molecules.

Recent Advances in Bioactive Flavonoid Hybrids Linked by 1,2,3-Triazole Ring Obtained by Click Chemistry

As a result of the biological activities of natural flavonoids, several synthetic strategies aiming to obtain analogues with improved potency and/or pharmacokinetic profile have been developed. Since the triazole ring has been associated with several biological activities and metabolic stability, hybridization with a 1,2,3-triazole ring has been increasingly reported over the last years. The feasible synthesis through copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) has allowed the accomplishment of several hybrids. Since 2017, almost 700 flavonoid hybrids conjugated with 1,2,3-triazole, including chalcones, flavones, flavanones and flavonols, among others, with antitumor, antimicrobial, antidiabetic, neuroprotective, anti-inflammatory, antioxidant, and antifouling activity have been reported. This review compiles the biological activities recently described for these hybrids, highlighting the mechanism of action and structure-activity relationship (SAR) studies.

Click Chemistry in Natural Product Modification

Click chemistry is perhaps the most powerful synthetic toolbox that can efficiently access the molecular diversity and unique functions of complex natural products up to now. It enables the ready synthesis of diverse sets of natural product derivatives either for the optimization of their drawbacks or for the construction of natural product-like drug screening libraries. This paper showcases the state-of-the-art development of click chemistry in natural product modification and summarizes the pharmacological activities of the active derivatives as well as the mechanism of action. The aim of this paper is to gain a deep understanding of the fruitful achievements and to provide perspectives, trends, and directions regarding further research in natural product medicinal chemistry.

1H-1,2,3-triazole embedded Isatin-Benzaldehyde-bis(heteronuclearhydrazones): design, synthesis, antimycobacterial, and cytotoxic evaluation

Rapid growth of global drug-resistant tuberculosis and urgent requirement for short treatment regimens is stimulating the need for discovery of new TB drugs. In this work, we report the design, synthesis and in vitro antimycobacterial evaluation of a library of isatin-derived bis(heteronuclear hydrazones). Evaluation results revealed that the inclusion of isoniazid core into 1H-1,2,3-triazole tethered isatin-benzaldehydes improved the antimycobacterial activity on tuberculosis mc² 6230 strain and significantly reduced the cytotoxicity against Vero cells. However, the introduction of semicarbazones/thiosemicarbazones or pyrazine-2-carbohydrazide produced the opposite effects. The compounds with isoniazid and polar-donating groups at the C-5 position of isatin emerged as the most promising conjugates with MIC₉₉  = 0.36 µg/ml. The most active compounds were non-cytotoxic to Vero cells (IC₅₀ >100 µg/ml) with selectivity indices >277.

Photoredox-catalyzed hydroxymethylation of β-ketoesters: application to the synthesis of [3.3.3] propellane lactones

Photoredox-catalysed hydroxymethylation of β-ketoesters substituted by an allyl subunit on the α-position afforded directly the corresponding bicyclic lactones possessing both a hydroxy group and an unsaturation. A subsequent regioselective iodoetherification led to the formation of original [3.3.3] propellane structures. Substitution of the iodine atom by various nucleophiles afforded highly functionnalized structures including triazolomethyl derivatives.

Synthesis of fullerenyl-1,2,3-triazoles by reaction of fullerenyl azide with terminal acetylenes

Fullerenyltriazoles were synthesized by the interaction of azidofullerene with terminal acetylenes, in which the heterocyclic fragment is directly attached to the fullerene core. The electrochemical studies of the synthesized triazole-containing fullerenes have proved that the potentials of the first reduction peaks are shifted to a less cathodic region compared to unmodified C₆₀. According to theoretical calculations, synthesized fullerene C₆₀ derivatives can be considered as promising acceptor components of organic solar cells.

A One-Pot Six-Component Reaction for the Synthesis of 1,5-Disubstituted Tetrazol-1,2,3-Triazole Hybrids and Their Cytotoxic Activity against the MCF-7 Cell Line

A high-order multicomponent reaction involving a six-component reaction to obtain the novel linked 1,5-disubstituted tetrazole-1,2,3-triazole hybrids in low to moderate yield is described. This one-pot reaction is carried out under a cascade process consisting of three sequential reactions: Ugi-azide, bimolecular nucleophilic substitution (SN2), and copper-catalyzed alkyne-azide reaction (CuAAC), with high atom and step-economy due the formation of six new bonds (one C-C, four C-N, and one N-N). Thus, the protocol developed offers operational simplicity, mild reaction conditions, and structural diversity. Finally, to evaluate the antitumoral potential of the synthetized molecules, a proliferation study was performed in the breast cancer (BC) derived cell line MCF-7. The hybrid compounds showed several degrees of cell proliferation inhibition with a remarkable effect in those compounds with cyclohexane and halogens in their structures. These compounds represent potential drug candidates for breast cancer treatment. However, additionally assays are needed to elucidate their complete effect over the cellular hallmarks of cancer.

Recent progress on betulinic acid and its derivatives as antitumor agents: a mini review

Natural products are one of the important sources for the discovery of new drugs. Betulinic acid (BA), a pentacyclic triterpenoid widely distributed in the plant kingdom, exhibits powerful biological effects, including antitumor activity against various types of cancer cells. A considerable number of BA derivatives have been designed and prepared to remove their disadvantages, such as poor water solubility and low bioavailability. This review summarizes the current studies of the structural diversity of antitumor BA derivatives within the last five years, which provides prospects for further research on the structural modification of betulinic acid.

Recent Progress in Catalytic Synthesis of 1,2,3-Triazoles

1,2,3-triazoles represent a functional heterocyclic core that has been at the center of modern organic chemistry since the beginning of click chemistry. Being a versatile framework, such an aromatic ring can be observed in uncountable molecules useful in medicine and photochemistry, just to name a few. This review summarizes the progress achieved in their synthesis from 2015 to today, with particular emphasis on the development of new catalytic and eco-compatible approaches. In doing so, we subdivided the report based on their degree of functionalization and, for each subparagraph, we outlined the role of the catalyst employed.

Design and synthesis of phenoxymethybenzoimidazole incorporating different aryl thiazole-triazole acetamide derivatives as α-glycosidase inhibitors

A novel series of phenoxymethybenzoimidazole derivatives (9a-n) were rationally designed, synthesized, and evaluated for their α-glycosidase inhibitory activity. All tested compounds displayed promising α-glycosidase inhibitory potential with IC₅₀ values in the range of 6.31 to 49.89 μM compared to standard drug acarbose (IC₅₀ = 750.0 ± 10.0 μM). Enzyme kinetic studies on 9c, 9g, and 9m as the most potent compounds revealed that these compounds were uncompetitive inhibitors into α-glycosidase. Docking studies confirmed the important role of benzoimidazole and triazole rings of the synthesized compounds to fit properly into the α-glycosidase active site. This study showed that this scaffold can be considered as a highly potent α-glycosidase inhibitor.

Diethyl (2-(4-Phenyl-1H-1,2,3-triazol-1-yl)benzyl) Phosphate

Here we describe a full structural elucidation of the diethyl (2-(4-phenyl-1H-1,2,3-triazol-1-yl)benzyl) phosphate. This compound is a common by-product present in the synthetic protocols to access the α-hydroxy phosphonate compounds through of a Phospha-Brook rearrangement. Thus, a complete NMR structural characterization of this rearrangement by-product was performed by 1H, 13C{1H}, 31P{1H}, COSY, HSQC, and HMBC NMR experiments. Additionally, we have demonstrated that the 1H-31P HMBC is a 2D heteroatom NMR experiment which combines the simple identification by 31P chemical shift with the detection sensitivity by 1H spectrum in a practical procedure.

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

Cu-catalyzed 1,3-dipolar cycloaddition of methyl 2-azidoacetate to iodobuta-1,3-diynes and subsequent Suzuki-Miyaura cross-coupling were used to synthesize new triazoles derivatives: 5-aryl-4-arylethynyl-1H-1,2,3-triazoles. Investigation of their optical properties by using UV absorption and fluorescence emission spectroscopies revealed that all molecules possess fluorescence properties with the values of the Stokes shift more than 100 nm. The photophysical behavior of the two most promising triazoles in polar and non-polar solvents was also studied.