Identification of novel human CC chemokine receptor 8 (CCR8) antagonists via the synthesis of naphthalene amide and sulfonamide isosteres.

The human CC chemokine receptor 8 (CCR8) has been extensively pursued as target for the treatment of various inflammatory disorders. More recently, the importance of CCR8 in the tumor microenvironment has been demonstrated, spurring the interest in CCR8 antagonism as therapeutic strategy in immuno-oncology. On a previously described naphthalene sulfonamide with CCR8 antagonistic properties, the concept of isosterism was applied, leading to the discovery of novel CCR8 antagonists with IC50 values in the nM range in both the CCL1 competition binding and CCR8 calcium mobilization assay. The excellent CCR8 antagonistic activity of the most potent congeners was rationalized by homology molecular modeling.

Exploration of 1,2,3-triazolo fused triterpenoids as inhibitors of human coronavirus 229E targeting the viral nsp15 protein.

The coronavirus disease-19 (COVID-19) pandemic has raised major interest in innovative drug concepts to suppress human coronavirus (HCoV) infections. We previously reported on a class of 1,2,3-triazolo fused betulonic acid derivatives causing strong inhibition of HCoV-229E replication via the viral nsp15 protein, which is proposedly related to compound binding at an intermonomer interface in hexameric nsp15. In the present study, we further explored the structure-activity relationship (SAR), by varying the substituent at the 1,2,3-triazolo ring as well as the triterpenoid skeleton. The 1,2,3-triazolo fused triterpenoids were synthesized by a multicomponent triazolization reaction, which has been developed in-house. Several analogs possessing a betulin, oleanolic acid, or ursolic acid core displayed favorable activity and selectivity (EC50 values for HCoV-229E: 1.6-3.5 µM), but neither of them proved as effective as the lead compound containing betulonic acid. The 18ß-glycyrrhetinic acid-containing analogs had low selectivity. The antiviral findings were rationalized by in silico docking in the available structure of the HCoV-229E nsp15 protein. The new SAR insights will aid the further development of these 1,2,3-triazolo fused triterpenoid compounds as a unique type of coronavirus inhibitors.

Voltammetric Sensing of Chloride Based on a Redox-Active Complex: A Terpyridine-Co(II)-Dipyrromethene Functionalized Anion Receptor Deposited on a Gold Electrode.

A redox-active complex containing Co(II) connected to a terpyridine (TPY) and dipyrromethene functionalized anion receptor (DPM-AR) was created on a gold electrode surface. This host-guest supramolecular system based on a redox-active layer was used for voltammetric detection of chloride anions in aqueous solutions. The sensing mechanism was based on the changes in the redox activity of the complex observed upon binding of the anion to the receptor. The electron transfer coefficient (α) and electron transfer rate constant (k0) for the modified gold electrodes were calculated based on Cyclic Voltammetry (CV) experiments results. On the other hand, the sensing abilities were examined using Square Wave Voltammetry (SWV). More importantly, the anion receptor was selective to chloride, resulting in the highest change in Co(II) current intensity and allowing to distinguish chloride, sulfate and bromide. The proposed system displayed the highest sensitivity to Cl- with a limit of detection of 0.50 fM. The order of selectivity was: Cl- > SO42- > Br-, which was confirmed by the binding constants (K) and reaction coupling efficiencies (RCE).

Synthesis of a 3,7-Disubstituted Isothiazolo[4,3-b]pyridine as a Potential Inhibitor of Cyclin G-Associated Kinase.

Disubstituted isothiazolo[4,3-b]pyridines are known inhibitors of cyclin G-associated kinase. Since 3-substituted-7-aryl-isothiazolo[4,3-b]pyridines remain elusive, a strategy was established to prepare this chemotype, starting from 2,4-dichloro-3-nitropyridine. Selective C-4 arylation using ligand-free Suzuki-Miyaura coupling and palladium-catalyzed aminocarbonylation functioned as key steps in the synthesis. The 3-N-morpholinyl-7-(3,4-dimethoxyphenyl)-isothiazolo[4,3-b]pyridine was completely devoid of GAK affinity, in contrast to its 3,5- and 3,6-disubstituted congeners. Molecular modeling was applied to rationalize its inactivity as a GAK ligand.

Synthesis and Investigation of Biological Activity of New Betulonic Acid Derivatives Containing 1,2,3-Triazole Fragments.

The results of this study showed that the compounds synthesized by the authors have significant potential due to their antibacterial and cytotoxic properties. The apparent antibacterial activity demonstrated by the compounds suggests that they are active antimicrobial agents against common microbial pathogens that cause various socially significant infectious diseases. Compound 6 showed pronounced antimicrobial activity against the Gram-positive test strain Staphylococcus aureus ATCC 6538, and compound 7 demonstrated pronounced antimicrobial activity against the Gram-negative test strain Escherichia coli ATCC 25922 (MIC = 6.3 µg/mL). This allowed us to consider these compounds to have great potential.

Palladium-Catalyzed Arylations towards 3,6-Diaryl-1,3a,6a-triazapentalenes and Evaluation of Their Fluorescence Properties.

Methyl 4-(1,3a,6a-triazapentalen-3-yl)benzoate (TAP1) shows interesting properties as a small molecule fluorophore. In the search for post-functionalization methods, palladium-catalyzed arylation reactions were demonstrated. Direct CH arylation reactions of TAP1 with various aryl halides resulted in 3,6-diaryltriazapentalenes TAP4, although mostly in poor yields. Bromination of TAP1 followed by Suzuki coupling, on the other hand, requires a more delicate procedure, but gave arylated products with the same regiochemistry (TAP4) in moderate to good yields. The structure of 6-phenyltriazapentalene TAP4a was confirmed by crystallographic analysis. In addition, the effect of the C6 arylation on the fluorescent properties of 3-aryl-1,3a,6a-triazapentalenes was studied in dichloromethane at room temperature and in 2-methyltetrahydrofuran at 77 K, while the photophysical properties of two saponified derivatives were measured in acetonitrile.

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines.

A novel and efficient base-catalyzed, transition-metal-free method for the synthesis of diheterocyclic compounds connected by an amidine linker, including apart from the common 1,2,3-triazole ring, either an additional pyrimidinedione, 4-nitroimidazole, isoxazole, 1,3,4-triazole, 2-oxochromone or thiazole ring, has been developed. The process was facilitated by a strong base and includes the cycloaddition reaction of 3,3-diaminoacrylonitriles (2-cyanoacetamidines) to heterocyclic azides followed by a Cornforth-type rearrangement to the final products. The reaction is tolerant to various N-monosubstituted 3,3-diaminoacrylonitriles and to different heterocyclic azides. The developed method has a broad scope and can be applied to obtain a variety of N-heteroaryl-1,2,3-triazole-4-carbimidamides with alkyl, allyl, propargyl, benzyl, cycloalkyl, and indolyl substituents at the N1 position .

Tandem Cycloaddition of Azides to 3,3-Diaminoacrylonitriles (2-Cyanoacetamidines) and Cornforth-Type Rearrangement as an Approach to 5-Amino-1,2,3-triazole-4-N-substituted Imidamides.

An efficient base-catalyzed, metal-free method for the synthesis of 5-amino-1,2,3-triazole-4-N-sulfonyl- and arylimidamides, directed by the structure of the amidine group, has been developed. It is based on a previously unknown tandem process involving cycloaddition reaction to 3,3-diaminoacrylonitriles (2-cyanoacetamidines) with aryl(alkyl)sulfonyl or aryl azides and Cornforth-type rearrangement. During the reaction optimization, different factors were found to facilitate the title reaction, which include the use of a strong base and N-mono- or N,N'-disubstituted 3,3-diaminoacrylonitriles. The reaction is tolerant to variously N-monosubstituted and N,N'-disubstituted 3,3-diaminoacrylonitriles and to various aryl- and aryl/alkyl sulfonyl azides. The developed method has a broad scope and can be applied to obtain a variety of 5-amino-1,2,3-triazole-4-carbimidamides bearing at the N1 position alkyl, allyl, propargyl, benzyl, cycloalkyl, and heteroaryl substituents and sulfonyl and aryl substituents at the amidine group. Post-cyclization reactions of prepared 5-amino-1,2,3-triazoles with DMF-DMA DMA-DMF leads to 1,2,3-triazolo[4,5-d]pyrimidines, 8-aza purine analogues demonstrating the applicability of the prepared compounds in organic synthesis.

Synthesis and structure-activity relationship study of phenoxybenzylpiperazine analogues as CCR8 agonists.

CCR8 agonists hold promise for the treatment of various auto-immune diseases. Despite the fact that phenoxybenzylpiperazine derivatives are known to be endowed with CCR8 agonistic activity, systematic structure-activity relationship studies have not been reported. In this study, ZK756326, a previously disclosed CCR8 agonist, was divided in various fragments and each subunit was subjected to structural modifications. All newly synthesized analogues were evaluated in a CCR8 calcium mobilization assay, revealing that only limited structural variation was tolerated in both phenyl rings and at the benzylic position. In contrast, various linkers gave analogues with good CCR8 agonistic potency. In addition, the presence of small substituents on the piperazinyl moiety or the exchange of the piperazinyl for a piperidinyl group afforded compounds with promising CCR8 agonism, with the most potent congener being 10-fold more potent than ZK756326.

Exploration of Pyrido[3,4-d]pyrimidines as Antagonists of the Human Chemokine Receptor CXCR2.

Upregulated CXCR2 signalling is found in numerous inflammatory, autoimmune and neurodegenerative diseases, as well as in cancer. Consequently, CXCR2 antagonism is a promising therapeutic strategy for treatment of these disorders. We previously identified, via scaffold hopping, a pyrido[3,4-d]pyrimidine analogue as a promising CXCR2 antagonist with an IC50 value of 0.11 µM in a kinetic fluorescence-based calcium mobilization assay. This study aims at exploring the structure-activity relationship (SAR) and improving the CXCR2 antagonistic potency of this pyrido[3,4-d]pyrimidine via systematic structural modifications of the substitution pattern. Almost all new analogues completely lacked the CXCR2 antagonism, the exception being a 6-furanyl-pyrido[3,4-d]pyrimidine analogue (compound 17b) that is endowed with similar antagonistic potency as the original hit.

Rhodium-Catalyzed Transannulation of 4,5-Fused 1-Sulfonyl-1,2,3-triazoles with Nitriles. The Selective Formation of 1-Sulfonyl-4,5-fused Imidazoles versus Secondary C-H Bond Migration.

The reactivity of readily available 4,5-fused-1-sulfonyl-1,2,3-triazoles was examined in the Rh(II)-catalyzed transannulation reaction with nitriles. We have come across the interesting observation that 1-sulfonyl cycloalkeno[d][1,2,3]triazoles that possess ß-hydrogens resist intramolecular ß-hydride migration and could serve as a new source of Rh-iminocarbenoids for intermolecular Rh(II)-catalyzed transannulation reactions. As a result, 1-sulfonyl cyclohexeno-, cyclohepteno-, dihydropyrano-, 5-phenyltetrahydrobenzo-, and 4,5-dihydronaphtho[d]imidazoles were synthesized from various nitriles in good yields. A one-pot methodology has also been executed for the synthesis of NH-imidazoles.

Thioisomünchnones versus Acrylamides via Copper-Catalyzed Reaction of Thioamides with Diazocarbonyl Compounds.

A novel carbenoid-mediated approach to thioisomünchnones was developed by intermolecular copper-catalyzed reactions of diazoacetamides with aromatic and heteroaromatic thioamides bearing a pyrrolidine moiety. The direction of the reaction can be switched toward 2-amino-2-heteroarylacrylamides by replacing the pyrrolidine with an aniline group or by the use of 2-cyano-2-diazoacetamides. The proposed mechanism and DFT calculations allowed us to rationalize the effect of substituents on the reaction direction. Effective methods were found for the synthesis of previously unknown both 2-heteroarylthioisomünchones and 2-heteroarylacrylamides, based on a wide scope of available reagents with a similar structure. Some of the synthesized thioisomünchnones exhibited multicolor fluorescence in the solid state and solutions.

Triphenylphosphonium-linked derivative of allobetulin: preparation, anticancer properties and their mechanism of inhibiting SGC-7901 cells proliferation.

As a very important lipophilic cation, the triphenylphosphonium moiety has been extensively studied in the development of anticancer agents. In this work, we adopted 1,2,3-triazole as the linking group to prepare triphenylphosphine salt-natural triterpenoid conjugates. We chose the rarely studied natural triterpenoid allobetulin as the lead compound and prepared three 1,2,3-triazole derivatives of allobetulin by the triazolization reaction which was developed by our group. The hydroxyl group was then replaced by bromination, and the target triphenylphosphonium-linked derivative of allobetulin 5 was obtained by reacting with triphenylphosphine. The cytotoxicity screening showed that the target compound 5 displayed same antiproliferative activity against tested cancer cells as the commercial anticancer drug doxorubicin but more active than cisplatin. Further studies on the mechanism of action indicated that compound 5 could obviously induce SGC-7901 cells apoptosis through the mitochondrial pathway, inducing cell cycle arrest. Moreover, compound 5 also could reduce the expression of Vimentin and increase the expression of E-cadherin to hinder Epithelial-mesenchymal transition (EMT). Since compound 5 has excellent anticancer activity, further research and development should be done.

A patent review on efficient strategies for the total synthesis of pazopanib, regorafenib and lenvatinib as novel anti-angiogenesis receptor tyrosine kinase inhibitors for cancer therapy.

Angiogenesis is an important and interesting scientific subject in the area of malignant tumours. Current research importance and interest are directed in connection to blood microvessels in cancer cell proliferation, tumour growth, and metastasis. Tyrosine kinases have been intensely implicated as therapeutic targets that affect the angiogenic process in tumour growth. In the last decades, targeting angiogenesis has led to achievements in the therapy of different carcinomas by different mechanisms, such as the utilization of anti-angiogenic small molecule receptor tyrosine kinase inhibitors. In the current review, we aim to track the advancements in the total synthesis of three receptor tyrosine kinase inhibitors (pazopanib, regorafenib and lenvatinib). This review surveys different synthetic routes for these three approved drugs (pazopanib, regorafenib and lenvatinib) which were previously published as patents (2014-2021). The purity of medicines is a very important factor during manufacturing so we have decided to review the purification process of these anticancer medicines as well. It should be noted that the different patents may have reported some procedures with different yields and purities for the synthesis of desired drug and their intermediates. In order to simplify the understanding of the contents of this review article, only the best results reported in each of these patents are reported for the synthesis of desired drug and their intermediates.

Carbocatalysis with pristine graphite: on-surface nanochemistry assists solution-based catalysis.

Carbocatalysis holds a privileged position as a sustainable alternative to metal-based catalysis. While the focus in solution-based catalytic processes generally lies on how the heterogeneous catalyst affects the solution composition, more attention has recently been given to the analysis of the carbon material itself. Various outstanding surface characterisation techniques, efficient in assessing the catalyst on-surface composition, are now available. These include high-resolution imaging tools such as scanning tunneling microscopy (STM), capable of bringing new insights into the processes determining rate and selectivity effects induced by carbocatalysts. In this regard, the use of self-assembly on graphite as a strategy to direct the outcome of chemical reactions has already shown great potential. This promising approach gives the scientific community the exciting prospect of rationalising selectivity in carbocatalysis with pristine graphite by linking in-solution and on-surface composition.

Advances in the Synthesis of Fused 1,2,3-Triazoles via a MCR-Intramolecular Azide-Alkyne Cycloaddition Approach.

The present review narrates several reports which deal with the synthesis of fused 1,2,3-triazole containing scaffolds following a sequential multicomponent reaction (MCR)-intramolecular azide-alkyne cycloaddition (IAAC) approach. The reviewed reactions were cleverly designed so as to incorporate azide and alkyne functionalities in the MCR product which was then subjected to IAAC. The review is divided into two sections based on the number of components in the multicomponent reaction. We have aimed at a critical discussion and also have highlighted either advantages or disadvantages of each methodology.

Recent Strategies in Transition-Metal-Catalyzed Sequential C-H Activation/Annulation for One-Step Construction of Functionalized Indazole Derivatives.

Designing new synthetic strategies for indazoles is a prominent topic in contemporary research. The transition-metal-catalyzed C-H activation/annulation sequence has arisen as a favorable tool to construct functionalized indazole derivatives with improved tolerance in medicinal applications, functional flexibility, and structural complexity. In the current review article, we aim to outline and summarize the most common synthetic protocols to use in the synthesis of target indazoles via a transition-metal-catalyzed C-H activation/annulation sequence for the one-step synthesis of functionalized indazole derivatives. We categorized the text according to the metal salts used in the reactions. Some metal salts were used as catalysts, and others may have been used as oxidants and/or for the activation of precatalysts. The roles of some metal salts in the corresponding reaction mechanisms have not been identified. It can be expected that the current synopsis will provide accessible practical guidance to colleagues interested in the subject.

Isolation and In Silico Anti-SARS-CoV-2 Papain-Like Protease Potentialities of Two Rare 2-Phenoxychromone Derivatives from Artemisia spp.

Two rare 2-phenoxychromone derivatives, 6-demethoxy-4`-O-capillarsine (1) and tenuflorin C (2), were isolated from the areal parts of Artemisia commutata and A. glauca, respectively, for the first time. Being rare in nature, the inhibition potentialities of 1 and 2 against SARS-CoV-2 was investigated using multistage in silico techniques. At first, molecular similarity and fingerprint studies were conducted for 1 and 2 against co-crystallized ligands of eight different COVID-19 enzymes. The carried-out studies indicated the similarity of 1 and 2 with TTT, the co-crystallized ligand of COVID-19 Papain-Like Protease (PLP), (PDB ID: 3E9S). Therefore, molecular docking studies of 1 and 2 against the PLP were carried out and revealed correct binding inside the active site exhibiting binding energies of -18.86 and -18.37 Kcal/mol, respectively. Further, in silico ADMET in addition to toxicity evaluation of 1 and 2 against seven models indicated the general safety and the likeness of 1 and 2 to be drugs. Lastly, to authenticate the binding and to investigate the thermodynamic characters, molecular dynamics (MD) simulation studies were conducted on 1 and PLP.

Jusanin, a New Flavonoid from Artemisia commutata with an In Silico Inhibitory Potential against the SARS-CoV-2 Main Protease.

A new flavonoid, Jusanin, (1) has been isolated from the aerial parts of Artemisia commutata. The chemical structure of Jusanin has been elucidated using 1D, 2D NMR, and HR-Ms spectroscopic methods to be 5,2',4'-trihydroxy-6,7,5'-trimethoxyflavone. Being new in nature, the inhibition potential of 1 has been estimated against SARS-CoV-2 using different in silico techniques. Firstly, molecular similarity and fingerprint studies have been conducted for Jusanin against co-crystallized ligands of eight different SARS-CoV-2 essential proteins. The studies indicated the similarity between 1 and X77, the co-crystallized ligand SARS-CoV-2 main protease (PDB ID: 6W63). To confirm the obtained results, a DFT study was carried out and indicated the similarity of (total energy, HOMO, LUMO, gap energy, and dipole moment) between 1 and X77. Accordingly, molecular docking studies of 1 against the target enzyme have been achieved and showed that 1 bonded correctly in the protein's active site with a binding energy of -19.54 Kcal/mol. Additionally, in silico ADMET in addition to the toxicity evaluation of Jusanin against seven models have been preceded and indicated the general safety and the likeness of Jusanin to be a drug. Finally, molecular dynamics simulation studies were applied to investigate the dynamic behavior of the Mpro-Jusanin complex and confirmed the correct binding at 100 ns. In addition to 1, three other metabolites have been isolated and identified to be сapillartemisin A (2), methyl-3-[S-hydroxyprenyl]-cumarate (3), and ß-sitosterol (4).

Isolation and In Silico SARS-CoV-2 Main Protease Inhibition Potential of Jusan Coumarin, a New Dicoumarin from Artemisia glauca.

A new dicoumarin, jusan coumarin, (1), has been isolated from Artemisia glauca aerial parts. The chemical structure of jusan coumarin was estimated, by 1D, 2D NMR as well as HR-Ms spectroscopic methods, to be 7-hydroxy-6-methoxy-3-[(2-oxo-2H-chromen-6-yl)oxy]-2H-chromen-2-one. As the first time to be introduced in nature, its potential against SARS-CoV-2 has been estimated using various in silico methods. Molecular similarity and fingerprints experiments have been utilized for 1 against nine co-crystallized ligands of COVID-19 vital proteins. The results declared a great similarity between Jusan Coumarin and X77, the ligand of COVID-19 main protease (PDB ID: 6W63), Mpro. To authenticate the obtained outputs, a DFT experiment was achieved to confirm the similarity of X77 and 1. Consequently, 1 was docked against Mpro. The results clarified that 1 bonded in a correct way inside Mpro active site, with a binding energy of -18.45 kcal/mol. Furthermore, the ADMET and toxicity profiles of 1 were evaluated and showed the safety of 1 and its likeness to be a drug. Finally, to confirm the binding and understand the thermodynamic characters between 1 and Mpro, several molecular dynamics (MD) simulations studies have been administered. Additionally, the known coumarin derivative, 7-isopentenyloxycoumarin (2), has been isolated as well as ß-sitosterol (3).