Copper supported modified magnetic carrageenan as a bio-based catalyst for the synthesis of novel scaffolds bearing the 1,2,3-triazole unit through the click reaction

The ongoing work delineates the design of a novel library of 1,2,3-triazole-attached phenylacetamides through molecular hybridization of propargyl and phenylacetamide derivatives. Copper-supported modified magnetic carrageenan serves as a green heterogeneous catalyst, ensuring high yield, efficient reaction times, high atom economy, utilization of an environmentally friendly catalyst from a natural source, and a straightforward workup procedure. The successful synthesis of the catalyst is confirmed and evaluated using various analytical techniques, while the synthetic compounds are characterized through 1H NMR and 13C NMR.

Design, synthesis, in vitro, and in silico evaluations of kojic acid derivatives linked to amino pyridine moiety as potent tyrosinase inhibitors

In the present study, novel series of kojic acid derivatives conjugated to amino pyridine moiety were designed and synthesized to explore their inhibitory activity against tyrosinase. To this end, the structure of all derivatives was characterized by 1H NMR, 13C NMR, FT-IR, and elemental analysis. Next, all derivatives were evaluated against tyrosinase compared to the kojic acid as positive control and exhibited different inhibitory potencies. Furthermore, the antioxidant potential of all derivatives was determined. The kinetic analysis of the most active agent revealed that 3-hydroxy-6-(hydroxymethyl)-2-((3-nitrophenyl)(pyridin-2-ylamino)methyl)-4H-pyran-4-one (4h) binds to the enzyme in the uncompetitive mode of action. The docking analysis and molecular dynamic simulations showed considerable binding affinity and significant interactions with tyrosinase enzyme to target the melanogenesis pathway, proposing them as potent candidates to control hyperpigmentation in the future.

Design, synthesis, in vitro, and in silico evaluations of benzo[d]imidazole-amide-1,2,3-triazole-N-arylacetamide hybrids as new antidiabetic agents targeting α-glucosidase

α-Glucosidase as a carbohydrate-hydrolase enzyme is a crucial therapeutic target for type 2 diabetes. In this work, benzo[d]imidazole-amide containing 1,2,3-triazole-N-arylacetamide derivatives 8a-n were synthesized and evaluated for their inhibitory activity against α-glucosidase. In vitro α-glucosidase inhibition assay demonstrated that more than half of the title compounds with IC₅₀ values in the range of 49.0-668.5 μM were more potent than standard inhibitor acarbose (IC₅₀ = 750.0 µM). The most promising inhibitor was N-2-methylphenylacetamid derivative 8c. Kinetic study revealed that compound 8c (K_i = 40.0 µM) is a competitive inhibitor against α-glucosidase. Significantly, molecular docking and molecular dynamics studies on the most potent compound showed that this compound with a proper binding energy interacted with important amino acids of the α-glucosidase active site. Study on cytotoxicity of the most potent compounds 8c, 8e, and 8g demonstrated that these compounds did not show cytotoxic activity against the cancer and normal cell lines MCF-7 and HDF, respectively. Furthermore, the ADMET study predicted that compound 8c is likely to be orally active and non-cytotoxic.

[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives as new therapeutic candidates against urease positive microorganisms: design, synthesis, pharmacological evaluations, and in silico studies

Regarding the important role of the urease enzyme as a virulence factor in urease-positive microorganisms in this study, new series of [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives were designed and synthesized. All compounds evaluated against urease enzyme exhibiting IC50 values of 0.87 ± 0.09 to 8.32 ± 1.21 µM as compared with thiourea as the positive control (IC50 = 22.54 ± 2.34 µM). The kinetic evaluations of 6a as the most potent derivative recorded a competitive type of inhibition. Molecular dynamic simulations of the 6a derivative were also conducted, showing that 6a occupied the active site with closed state. Antimicrobial activities of all derivatives were performed, and 6f (R = 3-Cl), 6g (R = 4-Cl), and 6h (R = 3,4-diCl) analogs demonstrated significant antifungal activities with MIC values of 1, 2, and 0.5 µg/mL compared with fluconazole with MIC = 2 µg/mL. Synthesized analogs also exhibited potent urease inhibitory activities against C. neoformans (IC50 = 83.7-118.7 µg/mL) and P. mirabilis (IC50 = 74.5-113.7 µg/mL), confirming their urease inhibitory potential. The results demonstrated that the designed scaffold could be considered a suitable pharmacophore to develop potent urease inhibitors.

Design, synthesis, in vitro, and in silico biological evaluations of coumarin-indole hybrids as new anti-α-glucosidase agents

BACKGROUND

A series of coumarin-indole hybrids was synthesized as the new α-glucosidase inhibitors. The title hybrids were considered as α-glucosidase inhibitors because had two active pharmacophores against α-glucosidase: coumarin and indole.

METHODS

The thirteen various derivatives 4a-m were synthesized, purified, and fully characterized. These compounds were evaluated against α-glucosidase in vitro and in silico. In silico pharmacokinetic studies of the most potent compounds were also performed.

RESULTS

Most of the title compounds exhibited high anti-α-glucosidase activity in comparison to standard drug acarbose. In particular, the phenoxy derivative 4d namely 3-((1H-indol-3-yl)(3-phenoxyphenyl)methyl)-4-hydroxy-2H-chromen-2-one showed promising activity. This compound is a competitive inhibitor against α-glucosidase and showed the lowest binding energy at the α-glucosidase active site in comparison to other potent synthesized compounds and acarbose.

CONCLUSION

Compound 4d can be a lead compound for further structural development to obtain effective and potent α-glucosidase inhibitors.

Design, synthesis, in vitro, and in silico enzymatic evaluations of thieno[2,3-b]quinoline-hydrazones as novel inhibitors for α-glucosidase

In the development of novel anti-α-glucosidase agents, we synthesized novel thieno[2,3-b]quinoline-hydrazones 9a-n by facile and efficient conventional chemical reactions. These compounds were characterized by IR, ¹H NMR, ¹³C NMR, and elemental analysis. Inhibitory activities of the title compounds were evaluated against yeast α-glucosidase. In particular, compounds 9c, 9d, and 9h exhibited high anti-α-glucosidase activity. Representatively, compound 9c with IC₅₀ = 1.3 µM, was 576-times more potent than positive control acarbose. Molecular docking study of the most active compounds showed that these compounds formed important binding interactions at α-glucosidase active site. Molecular dynamics study of compound 9c was also performed and the obtained results were compared with acarbose. Compounds 9c, 9d, and 9h were also evaluated for in silico druglikeness properties and ADMET prediction. These studies showed that the title most potent compounds could be exploited as drug candidates.

Pd@Py2PZ@MSN as a Novel and Efficient Catalyst for C–C Bond Formation Reactions

In this study, a novel catalyst is introduced based on the immobilization of palladium onto dipyrido (3,2-a:2′,3′-c) phenazine–modified mesoporous silica nanoparticles. The dipyrido (3,2-a:2′,3′-c) phenazine (Py₂PZ) ligand is synthesized in a simple method from the reaction of 1,10-phenanthroline-5,6-dione and 3,4-diaminobenzoic acid as starting materials. The ligand is used to functionalize mesoporous silica nanoparticles (MSNs) and modify their surface chemistry for the immobilization of palladium. The palladium-immobilized dipyrido (3,2-a:2′,3′-c) phenazine–modified mesoporous silica nanoparticles (Pd@Py₂PZ@MSNs) are synthesized and characterized by several characterization techniques, including TEM, SEM, FT-IR, TGA, ICP, XRD, and EDS analyses. After the careful characterization of Pd@Py₂PZ@MSNs, the activity and efficiency of this catalyst is examined in carbon–carbon bond formation reactions. The results are advantageous in water and the products are obtained in high isolated yields. In addition, the catalyst showed very good reusability and did not show significant loss in activity after 10 sequential runs.

Algal magnetic nickel oxide nanocatalyst in accelerated synthesis of pyridopyrimidine derivatives

This research presents a novel biological route for the biosynthesis of nickel oxide nanoparticles (NiO NPs) using marine macroalgae extract as a reducing and coating agent under optimized synthesis conditions. XRD and TEM analyses revealed that phytosynthesized NiO NPs are crystalline in nature with a spherical shape having a mean particle size of 32.64 nm. TGA results indicated the presence of marine-derived organic constituents on the surface of NiO NPs. It is found that biogenic NiO NPs with BET surface area of 45.59 m²g^-1 is a highly efficient catalyst for benign one-pot preparation of pyridopyrimidine derivatives using aqueous reaction conditions. This environmentally friendly procedure takes considerable advantages of shorter reaction times, excellent product yields (up to 96%), magnetically viable nanocatalyst (7 runs), low catalyst loadings, and free toxic chemical reagents.

Bi Metal-Organic Framework (Ce/Ni-BTC) as Heterogeneous Catalyst for the Green Synthesis of Substituted Chromeno[4, 3-b]quinolone under Solvent Free Condition

AIMS

Novel bi metal organic framework (b-MOF) is synthesized and used as a heterogeneous catalyst for the synthesis of chromeno[4, 3-b]quinolone derivatives via one-pot and solvent-free, four-component reaction of dimedone, aromatic aldehydes, 4-hydroxycoumarin and ammonium acetate at 110°C.

BACKGROUND

b-MOFs can be used as a heterogeneous catalyst in the synthesis of many organic compounds. The active and multi-purpose sites in b-MOFs provide a varied function in their catalytic applications. In this paper, reductive CES method is applied for the synthesis of Ce_0.47/Ni_0.53-BTC b-MOF. The resulting b-MOF was used as a heterogeneous catalyst for the synthesis of chromeno[4, 3-b]quinolone via one-pot and solvent-free, fourcomponent reaction of dimedone, aromatic aldehyde, 4-hydroxycoumarin and ammonium acetate at 110 °C.

METHOD

Ce_0.47/Ni_0.53-BTC was synthesized in an electrochemical cell composed of a stainless steel foil with a size of 5cm×5cm centered between two 5cm×5cm sized graphite plates as the anodes by the cathodic current density of 0.2 A/dm² and placed in a solution of cerium nitrate (0.3 g), nickel nitrate (0.3 g), H₃BTC (0.2 g) and NaNO₃ (0.1 g) in ethanol (500 mL). Ce_0.47/Ni_0.53-BTC (10 mg) was added to a mixture of dimedone (1 mmol), aromatic aldehyde (1 mmol), hydroxycoumarin (1 mmol) and ammonium acetate (1.5 mmol) and stirred at 110 °C under solvent-free conditions for 45 min. The reaction evolution was controlled by the TLC (hexane:ethyl acetate, 4:1). Then, boiling ethanol was added to the reaction mixture and stirred at room temperature for 15 min. After the reaction completion, the catalyst was separated by centrifuge. Finally, the reaction mixture was placed in an ice bath, which resulted in a white solid product and recrystallized from ethanol to give the pure product.

RESULT

The b-MOF catalyst showed very good efficiency in the synthesis of the desired compounds and can be easily recovered by centrifuge and reused at least five times without a decrease in catalytic activity.

CONCLUSION

In this report, a novel bi metal-organic framework (Ce0.47/Ni0.53-BTC) is synthesized via the cathodic electrosynthesis method. The synthesized b-MOF is fully characterized by several characterization methods. The catalytic activity of Ce0.47/Ni0.53-BTC is investigated in the synthesis of chromeno[4, 3-b]quinolone derivatives via one-pot four-component reaction of dimedone, aromatic aldehyde, 4-hydroxycoumarin and ammonium acetate. The reaction optimization results showed that the highest isolated yield was obtained when the reaction was performed in solvent-free conditions at 110 °C. The catalyst showed to be highly efficient in the synthesis of the desired compounds and performing the reaction utilizing various starting materials gave the products in good isolated yields, which proves the generality and the scope of the method. The catalyst could easily be recovered by centrifuge and reused at least five times without a decrease in catalytic activity.

One-pot multi-component process for the synthesis of 4-azaphenanthrene-3,10-dione, 1,8-dioxo-octahydroxanthene and tetrahydrobenzo[b]pyran derivatives catalyzed by the deep eutectic solvent choline chloride-oxalic acid

An effective method based on choline chloride (ChCl)-oxalic acid (Ox) deep eutectic solvent was proposed for the synthesis of 4-azaphenanthrene-3,10-dione, 1,8-dioxo-octahydroxanthene and tetrahydrobenzo[b]pyran derivatives. The eutectic mixture worked as both the solvent and acidic catalyst for conversion. The impacts of different variables, including the composition and volume of ChCl-Ox, and temperature, on reaction yield were studied for optimization. The crucial advantages of this process are simplicity of the experimental procedure, high yields, short reaction times, high recyclability, and the use of safe and inexpensive components.

Metal-free, air-promoted, radical-mediated arylation of benzoquinone with phenylhydrazines

An efficient, economic, and air-promoted metal-free method for direct arylation of benzoquinone with phenylhydrazines was developed. This approach leads to the formation of corresponding [1,1′-biphenyl]-2,5-dione derivatives as biological and pharmaceutical materials of interest in good yields, under mild reaction conditions, and at ambient temperature.

A Convenient Method for the Synthesis of Chromeno[4,3-b]pyridines Via Three-component Reaction

AIM AND OBJECTIVE

The importance of Chromeno[4,3-b]pyridines in bioactive compounds, highlighted the ongoing research on developing novel methods for the construction of this heterocyclic scaffold. Regarding the advantageous features of multi-component reactions in organic synthesis, we will try to synthesize pyridocoumarins through this method.

MATERIALS AND METHODS

Chromeno[4,3-b]pyridines were conveniently prepared from a threecomponent condensation reaction between 4-hydroxy coumarin, ammonia and ethyl 2,4-dioxo-4- arylbutanoates in refluxing n-propanol. The synthesized compounds were characterized by NMR, IR and Mass spectroscopy.

RESULTS

The reaction proceeded through an in situ formed 4-amino coumarin, affording eight new target compounds in good yields.

CONCLUSION

This method introduce a novel approach to ethyl 4-aryl-5-oxo-5H-chromeno[4,3- b]pyridine-2-carboxylate derivatives and allow organic chemists to prepare 4-aminocoumarin in reaction medium.

An Efficient Four-Step Approach Toward Fused Triazino[1,6-a] Quinazolines

Herein, we describe a simple, four-step process for the preparation of 1,2,3-triazino[1,6- a]quinazolin-13-ones. This method involves ring-opening, quinazoline-forming condensation, reduction, diazotization accompanied by rapid intramolecular cyclization in the last step afforded the desired products with structurally complex heterocyclic core in excellent to high yields.