Design, synthesis, and evaluation of novel substituted imidazo[1,2-c]quinazoline derivatives as potential α-glucosidase inhibitors with bioactivity and molecular docking insights

α-Glucosidase inhibitors are important in the treatment of type 2 diabetes by regulating blood glucose levels and reducing carbohydrate absorption. The present study focuses on identifying new inhibitors bearing imidazo[1,2-c]quinazoline backbone through multi-step synthesis. The inhibitory potencies of the novel derivatives were tested against Saccharomyces cerevisiae α-glucosidase, revealing IC50 values ranging from 50.0 ± 0.12 µM to 268.25 ± 0.09 µM. Among them, 2-(4-(((2,3-diphenylimidazo[1,2-c]quinazolin-5-yl)thio)methyl)-1H-1,2,3-triazol-1-yl)-N-(2-methoxyphenyl)acetamide (19e) and 2-(4-((benzo[4,5]imidazo[1,2-c]quinazolin-6-ylthio)methyl)-1H-1,2,3-triazol-1-yl)-N-(2-methoxyphenyl)acetamide (27e) emerged as the most potent inhibitors and were further investigated in various assessments. Finally, molecular docking studies were performed to reveal the crucial binding interactions and to confirm the results obtained from structure-activity relationship (SAR) analysis.

Substituent-Oriented Synthesis of Substituted Pyridines/Pyrido[3,2-C]coumarins via Sequential Reactions of α-H and Me/Aryl Substituted Oxime Acetates and 3-Formylchromones

A facile one pot sequential and highly chemoselective synthesis of substituted pyridines/pyrido[3,2-c]coumarins has been developed from oxime acetates and 3-formylchromones in the presence of FeCl2. This reaction was oriented by different substituents on the α-position (H, methyl/aryl) of oxime acetates. Mechanistic investigations suggested that substituted pyridines were formed via intramolecular aza-Michael addition followed by ring opening, while pyrido[3,2-c]coumarins were formed via intermolecular Michael addition. Besides, anti-TB activity was screened for some of the synthesized pyridines. Among the tested compounds, 3ga, 3ha, 3ja, 3ma, 3ac, 4pa, 4pb and 4sb were found to have good activity with an MIC of 12.5 μg/mL.

A new route to the synthesis of 2-hydrazolyl-4-thiazolidinone hybrids, evaluation of α-glucosidase inhibitory activity and molecular modeling insights

One of the multifactorial worldwide health syndromes is diabetes mellitus which is increasing at a disturbing rate. The inhibition of α-glucosidase, an enzyme that catalyzes starch hydrolysis in the intestine, is one helpful therapeutic approach for controlling hyperglycemia related to type-2 diabetes. To discover α-glucosidase inhibitors, some 2-hydrazolyl-4-thiazolidinone hybrids (3a-e) were synthesized from new one-pot reaction procedures. Next, their chemical structures were confirmed by 1H NMR, 13C NMR, and FT-IR spectra, and elemental analysis technique. Then, the α-glucosidase inhibitory activity of the titled compounds was evaluated. Among them, derivatives 3b and 3c revealed the highest activity against α-glucosidase compared to acarbose as a drug. Enzyme kinetic studies of the most active derivative (3b) indicated a competitive inhibition. Finally, molecular modeling studies were accomplished to describe vital interactions of the most potent compounds (3b and 3c) with the α-glucosidase enzyme.

An efficient and simple approach for synthesizing indazole compounds using palladium-catalyzed Suzuki-Miyaura cross-coupling

A series of indazole derivatives (6a-6i and 7a-7i) has been synthesized using Suzuki Miyaura cross-coupling with a palladium catalyst from readily available starting materials. An efficient and reliable methodology was employed for the synthesis, and the compounds were thoroughly characterized using 1H NMR, 13C NMR, FT-IR, and HRMS analysis to confirm their structural integrity and purity. Density function theory (DFT) computation identified four compounds (6g, 6h, 7g, and 7h) with significant energy band gaps. Additionally, the molecular electrostatic potential study highlighted the distinct electrical characteristics of these indazole molecules. Subsequent molecular docking investigations were carried out using the AUTODOCK method with two separate protein data bank (PDB) structures (6FEW, 4WA9) involved in renal cancer pathways. The results showed that eight substances PDB: 6FEW (6g, 6h, 7g, and 7h) and PDB: 4WA9 (6a, 6c, and 7c, 7g) had the highest binding energies, indicating their potential as therapeutic agents for treating kidney cancer.

Spirothiazolidine-Derivative on Silver Nanoparticles and Carbon Nanotubes: Evaluation of Antibacterial, Anti-Fungal, Anti-Inflammatory, Antioxidant and Gastroprotective Activities

This study aims to develop innovative heterocyclic nanocomposites incorporating silver nanoparticles (SNPs) for potential therapeutic applications targeting infections, gastric ulceration, inflammation, and oxidative damage. By synthesizing new derivatives of spiro-thiazolidine-carbonitrile (Py-ST-X) and incorporating them into Ag nanoparticles (AgNPs) and carbon nanotubes (CNTs), we have prepared Ag@Py-ST-X and Ag@Py-ST-X@CNT nanocomposites, respectively. The physical properties of these materials were studied using XRD, TEM, SEM, and Zeta potential techniques. In our investigation involving rats with gastric ulcers, we observed noteworthy inhibitory effects on gastric acid enzyme activity, specifically H+/K+ATPase, by Ag@Py-ST-NO2 and Ag@Py-ST-Br nanocomposites, demonstrating reductions of 25 and 34%, respectively, compared to untreated ulcers. Nanotubulation of these compounds further improved their inhibitory efficacy to 29 and 45%, respectively. Additionally, these nanoparticles showed the most potent myeloperoxidase (MPO)-inhibitory activity, demonstrating 36 and 49% inhibition, respectively, with nanotubulated versions reaching 44 and 53%. Moreover, Ag@Py-ST-NO2@CNT and Ag@Py-ST-Br@CNT nanotubes showed significant antioxidant activity, reducing thiobarbituric acid reactive substances (TBARS) by 35 and 51%, and hydrogen peroxide (H2O2) levels by 49 and 71%, respectively. These therapeutic effects were confirmed by reductions in gastric surface area (GSA) by 44% and 52%, a decrease in ulcer index (UI) from 80% to 44 and 38%, and an increase in curative index (CI) from 19 to 55 and 62% following administration of Ag@Py-ST-NO2@CNT and Ag@Py-ST-Br@CNT, respectively. Histological studies support these findings, suggesting the potential of these nanocomposites as promising candidates for treating various disorders.

Antibacterial and Anticandidal Activity of the Nanostructural Composite of a Spirothiazolidine-Derivative Assembled on Silver Nanoparticles

Our aims in this work are the preparation of an ionic liquid based on heterocyclic compounds with Ag nanoparticles and the investigation of its application as an antibacterial and anticandidal agent. These goals were achieved through the fabrication of an ionic liquid based on Ag nanoparticles with 5-Amino-3-(4-fluorophenyl)-N-hexadecyl-7-(4-methylphenyl)-2-H spiro[cyclohexane1,2'-[1,3]thiazolo [4,5-b]pyridine]-6-carbonitrile (P16). The nanostructure of the prepared ionic liquid was characterized using techniques such as FTIR, 1HNMR, 13CNMR, UV, SEM, and TEM. The biological activity of the prepared compound (P16) and its nanocomposites with Ag nanoparticles was tested using five clinical bacteria (Pseudomonas aeruginosa 249; Escherichia coli 141; Enterobacter cloacae 235; Staphylococcus epidermidis BC 161, and methicillin-resistant S. aureus 217), and three Candida species (Candida utilis ATCC 9255; C. tropicalis ATCC 1362, and C. albicans ATCC 20402). The FTIR, 1HNMR, and 13CNMR results confirmed the chemical structure of the synthesized P16 compound. The nanostructure of the prepared ionic liquid was determined based on data obtained from the UV, SEM, and TEM tests. The antibacterial and anticandidal results showed that the biological activity of the compound (P16) was enhanced after the formation of nanocomposite structures with Ag nanoparticles. Moreover, the biological activity of the compound itself (P16) and that of its nanocomposite structure with Ag nanoparticles was higher than that of ampicillin and amphotericin B, which were used as control drugs in this work.

Synthesis, in vitro potency of inhibition, enzyme kinetics and in silico studies of quinoline-based α-glucosidase inhibitors

Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target α-glucosidase, which catalyzes starch hydrolysis in the intestine. In an attempt to find potential α-glucosidase inhibitors, a series of twenty new quinoline linked benzothiazole hybrids (8a-t) were synthesized in good yields from suitable reaction procedures and their chemical structures were analyzed by 1HNMR, 13CNMR, IR, and ESI-MS analysis. The synthesized derivatives further screened for their activity against α-glucosidase. Among them, compounds 8b, 8h, 8n and 8o exhibited remarkable α-glucosidase inhibitory activity with IC50 values ranging from 38.2 ± 0.3 to 79.9 ± 1.2 µM compared with standard drug acarbose (IC50 = 750.0 ± 2.0 µM). Enzyme kinetic studies of the most active compound (8h) indicated a non-competitive inhibition with Ki value of 38.2 µM. Moreover, the homology modeling, molecular docking and molecular dynamics simulation studies were conducted to reveal key interactions between the most active compound 8h and the targeted enzyme. These results are complementary to the experimental observations. In order to predict the druggability of the novel derivatives, the pharmacokinetic properties were also applied. These findings could be useful for the design and development of new α-glucosidase inhibitors.

Ligand-based designing of DPP-4 inhibitors via hybridization; synthesis, docking, and biological evaluation of pyridazine-acetohydrazides

A series of novel pyridazine-acetohydrazide hybrids were designed, synthesized, and evaluated for their in vitro and in vivo antihyperglycemic activity. In this context, pyridazine-acetohydrazides (6a-6p) were synthesized by coupling substituted aldehyde with 2-(5-cyano-6-oxo-3,4-diphenylpyridazine-1-6H-yl) acetohydrazide, which was prepared via the reaction of pyridazine ester with hydrazine hydrate. The molecular docking study was carried out to examine the binding affinities and interaction of designed compounds against the DPP-4 enzyme. Compounds 6e, 6f, 6l, and 6n exhibited interaction with active residue. In silico ADMET properties, and toxicity studies corroborated that compounds were found to have good bioavailability and less toxic. The synthesized compounds were further estimated for in vitro DPP-4 activity. Compounds 6e and 6l were found as the most effective DPP-4 inhibitor in this series with IC50 values (6.48, 8.22 nM) when compared with sitagliptin (13.02 nM). According to the toxicity assay compound, 6l showed very less toxicity at a higher concentration so further selected for the in vivo antihyperglycemic activity.

Diphenyl-substituted triazine derivatives: synthesis, α-glucosidase inhibitory activity, kinetics and in silico studies

Background: Diabetes mellitus (DM) is a chronic disorder, considered to be a major global health challenge in the 21st century. α-Glucosidase enzyme is a well-known drug target to treat Type II DM. Methods: A new library of biphenyl-substituted triazines was synthesized and confirmed by various spectroscopic techniques. Results: All compounds showed potent α-glucosidase inhibitory activity, with IC50 values ranging from 35.35 ± 0.34 to 564.41 ± 0.91 μM, as the standard acarbose, IC50 value of 750.7 ± 0.13 μM. Our in silico study has predicted key interactions with the enzyme's active site. Drug-likeness and absorption, distribution, metabolism, excretion and toxicity were also studied. Conclusion: This study has identified a range of potential hits against the α-glucosidase enzyme that may serve as antidiabetic agents after further investigations.

One-Pot Synthesis of Pentasubstituted Pyridines following the Gold(I)-Catalyzed Aza-Enyne Metathesis/6π-Electrocyclization-Aromatization Sequence

The one-pot de novo synthesis of pentasubstituted pyridines was realized following the process of Au(I)-autotandem catalysis and subsequent aromatization. The process involves aza-enyne metathesis with aryl propiolates to yield 1-azabutadienes and their addition/6π-electrocyclization sequence with the other propiolate units. The resultant 1,4-dihydropyridines were aromatized to furnish the pyridines in the presence of atmospheric oxygen. The aryl propiolates were regioselectively incorporated into the ring system to afford 2-arylpyridines as the sole product.

One-pot domino synthesis of five- and six-membered fused dihydropyridines promoted by PPh3-NBS in aqueous medium

A facile one-pot synthesis of five- and six-membered fused dihydropyridines such as chromenodihydropyridines, pyrazolodihydropyridines and isoxazolopyridines was accomplished for the first time by employing PPh₃-NBS via a formal [3 + 2 + 1] cycloaddition of 1,3-bisnucleophiles (i.e., 2-aminochromone, 4-aminochromone, 5-aminopyrazole and 5-aminoisoxazole), β-enaminones and aldehydes in aqueous medium. The present approach involves a Michael type addition followed by intramolecular cyclization leading to the formation of two new C-C bonds and one C-N bond. High compatibility and excellent yields are the advantages of this protocol.

Regioselective syntheses of 2-oxopyridine carbonitrile derivatives and evaluation for antihyperglycemic and antioxidant potential

A library of 2-oxopyridine carbonitriles 1-34 was synthesized by regioselective nucleophilic substitution reactions. In the first step, a one-pot multicomponent reaction yield pyridone intermediates. The resulting pyridone intermediates were then reacted with phenacyl halides in DMF and stirred at 100 °C for an hour to afford the desired compounds in good yields. Structures of synthetic molecules were characterized by EI-MS, HREI-MS, ¹H NMR, and ¹³C NMR, and all thirty-four (34) compounds were found to be new. All synthetic compounds were examined for antidiabetic and antioxidant potential. The compounds exhibited α-glucosidase inhibitory potential in the range of IC₅₀ = 3.00 ± 0.11-43.35 ± 0.67 μM and α-amylase inhibition potential in the range of IC₅₀ = 9.20 ± 0.14-65.56 ± 1.05 μM. Among the tested compounds, 1 showed the most significant α-glucosidase inhibitory activity, with an IC₅₀ value of 3.00 ± 0.11 μM, while the most active compound against α-amylase was 6, with an IC₅₀ value = 9.20 ± 0.14 μM. The kinetic studies and analysis indicated that the compounds followed the competitive mode of inhibition. In addition, the molecular docking studies showed the interaction profile of all molecules with the binding site residues of α-glucosidase and α-amylase enzymes.

Novel Set of Highly Substituted Bis-pyridines: Synthesis, Molecular Docking and Drug-Resistant Antibacterial Profile

Aims: Development of antimicrobial agents having the ability to prevent bacterial biofilm formation which causes serious health problems, especially with antibiotic-resistant bacterial strains. Materials and methods: The use of 1,3-diaryl enones as structural motifs to access the pyridine core. Antimicrobial activities of the synthesized compounds against methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus and vancomycin-resistant S. aureus bacterial strains were investigated. Results: The newly synthesized bis-enones were used as building blocks to access some novel highly substituted bis-pyridine derivatives. Several novel bis-compounds showed great bacterial biofilm eradication activity. Conclusion: A new series of bis-chalcones was synthesized and their structural diversity was exploited to access the corresponding, more biologically active, pyridine core. These bis-pyridines showed respectable antibacterial activities against various drug-resistant bacterial strains: namely, methicillin-susceptible, methicillin-resistant and vancomycin-resistant S. aureus.

Synthesis and Evaluation of Coumarin-Chalcone Derivatives as α-Glucosidase Inhibitors

Coumarin and chalcone, two important kinds of natural product skeletons, both exhibit α-glucosidase inhibitory activity. In this work, coumarin-chalcone derivatives 3 (a∼v) were synthesized, and their α-glucosidase inhibitory activity was screened. The results showed that all synthetic derivatives (IC50: 24.09 ± 2.36 to 125.26 ± 1.18 μM) presented better α-glucosidase inhibitory activity than the parent compounds 3-acetylcoumarin (IC50: 1.5 × 105 μM) and the positive control acarbose (IC50: 259.90 ± 1.06 μM). Among them, compound 3t displayed the highest α-glucosidase inhibitory activity (IC50: 24.09 ± 2.36 μM), which was approximately 10 times stronger than that of acarbose. The kinetic assay of 3t (KI = 18.82 μM, KIS = 59.99 μM) revealed that these compounds inhibited α-glucosidase in a mixed-type manner. Molecular docking was used to simulate the interaction between α-glucosidase and compound 3t.

Recent Advances in Organic Synthesis of 3-Amino- or 4-Aminocoumarins

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Coumarin is a privileged scaffold that contains the unique 2H-chromen-2-one motif, and its derivatives are widely distributed in nature, especially in plants. In recent years, due to their diverse pharmacological activities and remarkable photochemical properties, they have attracted significant attention from scientists, which has also prompted the research on the synthesis approaches and the availability of substrates for these compounds. This article is a brief description of the methods for the synthesis of various coumarin derivatives via two- or multi-component reactions involving 3-amino or 4-aminocoumarin reported during 2015-2021. This review may help expand the development of various analogues with coumarin as the basic unit.

Pyridine: the scaffolds with significant clinical diversity

The nitrogen-bearing heterocycle pyridine in its several analogous forms occupies an important position as a precious source of clinically useful agents in the field of medicinal chemistry research. This privileged scaffold has been consistently incorporated in a diverse range of drug candidates approved by the FDA (Food and Drug Administration). This moiety has attracted increasing attention from several disease states owing to its ease of parallelization and testing potential pertaining to the chemical space. In the next few years, a larger share of novel pyridine-based drug candidates is expected. This review unifies the current advances in novel pyridine-based molecular frameworks and their unique clinical relevance as reported over the last two decades. It highlights an inclination to the use of pyridine-based molecules in drug crafting and the subsequent emergence of several potent and eligible candidates against a range of diversified diseases.

The nitrogen-bearing heterocycle pyridine in its several analogous forms occupies an important position as a precious source of clinically useful agents in the field of medicinal chemistry research.

Vinylazides: versatile synthons and magical precursors for the construction of N-heterocycles

Nowadays, application of vinylazides as precursors is a key method for the construction of N-heterocycles in organic synthesis. These versatile three-atom synthons can be converted into intermediates such as 2H-azirines, iminyl radicals, iminyl metal complexes, iminyl inions and nitrilium ions that subsequently afford a wide range of polyfunctional cyclic nitrogen-containing compounds. In this review, the reactions of vinylazides leading to these products (in the last decade) are categorized based on the types of the resulting N-heterocyclic rings and a brief and concise description of the reaction mechanisms is presented.

The Expanding Role of Pyridine and Dihydropyridine Scaffolds in Drug Design

Pyridine-based ring systems are one of the most extensively used heterocycles in the field of drug design, primarily due to their profound effect on pharmacological activity, which has led to the discovery of numerous broad-spectrum therapeutic agents. In the US FDA database, there are 95 approved pharmaceuticals that stem from pyridine or dihydropyridine, including isoniazid and ethionamide (tuberculosis), delavirdine (HIV/AIDS), abiraterone acetate (prostate cancer), tacrine (Alzheimer's), ciclopirox (ringworm and athlete's foot), crizotinib (cancer), nifedipine (Raynaud's syndrome and premature birth), piroxicam (NSAID for arthritis), nilvadipine (hypertension), roflumilast (COPD), pyridostigmine (myasthenia gravis), and many more. Their remarkable therapeutic applications have encouraged researchers to prepare a larger number of biologically active compounds decorated with pyridine or dihydropyridine, expandeing the scope of finding a cure for other ailments. It is thus anticipated that myriad new pharmaceuticals containing the two heterocycles will be available in the forthcoming decade. This review examines the prospects of highly potent bioactive molecules to emphasize the advantages of using pyridine and dihydropyridine in drug design. We cover the most recent developments from 2010 to date, highlighting the ever-expanding role of both scaffolds in the field of medicinal chemistry and drug development.

Multicomponent reaction for the synthesis of new 1,3,4-thiadiazole-thiazolidine-4-one molecular hybrids as promising antidiabetic agents through α-glucosidase and α-amylase inhibition

A simple and efficient protocol was developed to synthesize a new library of thiazolidine-4-one molecular hybrids (4a-n) via a one-pot multicomponent reaction involving 5-substituted phenyl-1,3,4-thiadiazol-2-amines, substituted benzaldehydes and 2-mercaptoacetic acid. The synthesized compounds were evaluated in vitro for their antidiabetic activities through α-glucosidase and α-amylase inhibition as well as their antioxidant and antimicrobial potentials. Compound 4e exhibited the most promising α-glucosidase and α-amylase inhibition with an IC50 value of 2.59 μM, which is ~1.5- and 14-fold superior as compared to the standard inhibitor acarbose. Structure-activity relationship (SAR) analysis revealed that the nature and position of substituents on the phenyl rings had a significant effect on the inhibitory potency.

Novel Coumarin Containing Dithiocarbamate Derivatives as Potent α-Glucosidase Inhibitors for Management of Type 2 Diabetes

BACKGROUND

α-Glucosidase is a hydrolyzing enzyme that plays a crucial role in the degradation of carbohydrates and starch to glucose. Hence, α-glucosidase is an important target in carbohydrate mediated diseases such as diabetes mellitus.

OBJECTIVE

In this study, novel coumarin containing dithiocarbamate derivatives 4a-n were synthesized and evaluated against α-glucosidase in vitro and in silico.

METHODS

These compounds were obtained from the reaction between 4-(bromomethyl)-7- methoxy-2H-chromen-2-one 1, carbon disulfide 2, and primary or secondary amines 3a-n in the presence of potassium hydroxide and ethanol at room temperature. In vitro α-glucosidase inhibition and kinetic study of these compounds were performed. Furthermore, a docking study of the most potent compounds was also performed by Auto Dock Tools (version 1.5.6).

RESULTS

Obtained results showed that all the synthesized compounds exhibited prominent inhibitory activities (IC50 = 85.0 ± 4.0-566.6 ± 8.6 μM) in comparison to acarbose as a standard inhibitor (IC50 = 750.0 ± 9.0 μM). Among them, the secondary amine derivative 4d with pendant indole group was the most potent inhibitor. Enzyme kinetic study of the compound 4d revealed that this compound competes with a substrate to connect to the active site of α-glucosidase and therefore is a competitive inhibitor. Moreover, a molecular docking study predicted that this compound interacted with the α-glucosidase active site pocket.

CONCLUSION

Our results suggest that the coumarin-dithiocarbamate scaffold can be a promising lead structure for designing potent α-glucosidase inhibitors for the treatment of type 2 diabetes.

Design, synthesis, molecular docking, and in vitro α-glucosidase inhibitory activities of novel 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines against yeast and rat α-glucosidase

In an attempt to find novel, potent α-glucosidase inhibitors, a library of poly-substituted 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines 3a-ag have been synthesized through heating a mixture of 2-aminobenzimidazoles 1 and α-azidochalcone 2 under the mild conditions. This efficient, facile protocol has been resulted into the desirable compounds with a wide substrate scope in good to excellent yields. Afterwards, their inhibitory activities against yeast α-glucosidase enzyme were investigated. Showing IC50 values ranging from 16.4 ± 0.36 µM to 297.0 ± 1.2 µM confirmed their excellent potency to inhibit α-glucosidase which encouraged us to perform further studies on α-glucosidase enzymes obtained from rat as a mammal source. Among various synthesized 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-a]pyrimidines, compound 3k exhibited the highest potency against both Saccharomyces cerevisiae α-glucosidase (IC50 = 16.4 ± 0.36 μM) and rat small intestine α-glucosidase (IC50 = 45.0 ± 8.2 μM). Moreover, the role of amine moiety on the observed activity was studied through substituting with chlorine and hydrogen resulted into a considerable deterioration on the inhibitory activity. Kinetic study and molecular docking study have confirmed the in-vitro results.

Efficient Route for the Synthesis of Diverse Heteroannelated 5-Cyanopyridines

The new efficient, convenient protocol for the synthesis of heteroannelated 3-cyanopyridines and pyrimidines starting from diverse aminoheterocycles and 3,3-dimethoxy-2-formylpropionitrile sodium salt was elaborated. The advantages and improvements of the procedure compared to previously known methods are shown. The scope and limitations of the method are determined. The impact of the structural features on regioselectivity are discussed. The preparativeness, scalability, and application scope of the elaborated protocol are demonstrated by the synthesis of five heteroannelated 3-cyanopyridines in quantities up to 100 grams.

4-Aminocoumarin derivatives: synthesis and applications

4-Aminocoumarins represent an important class of a versatile scaffold in organic synthesis and have been consistently used as a building block in organic chemistry for the synthesis of different heterocyclic compounds.

The synthesis, biological evaluation and fluorescence study of chromeno[4,3-b]pyridin/quinolin-one derivatives, the backbone of natural product polyneomarline C scaffolds: a brief review

This review presents the synthesis, biological and fluorescence study of chromeno[4,3-b]pyridin/quinolin-ones via classical reactions including metal-catalyzed and green reaction protocols.

4-Chloro-3-formylcoumarin as a multifaceted building block for the development of various bio-active substituted and fused coumarin heterocycles: a brief review

This review presents the diverse synthesis of 3,4-substituted coumarins and 5-, 6- and 7-membered ring fused coumarins using 4-chloro-3-formylcoumarin as the precursor via classical reactions including metal-catalyzed and green reaction protocols.

Discovery of Novel Coumarin Analogs against the α-Glucosidase Protein Target of Diabetes Mellitus: Pharmacophore-Based QSAR, Docking, and Molecular Dynamics Simulation Studies

Diabetes mellitus (DM) is a chronic metabolic disease, the third killer of mankind. The finding of potent drugs against diabetes remains challenging. In the present study, coumarin derivatives with known biological activity against diabetic protein have been used to predict functional groups' positions on coumarin derivatives. α-Glucosidase is a brush border membrane-bound lysosomal enzyme from the hydrolase enzyme family. It plays an important role in the metabolism of glycoproteins. Inhibitors of lysosomal α-glucosidase can reduce postprandial hyperglycemia. Due to this, lysosomal α-glucosidase is a good therapeutic target for drugs. A total of 116 coumarin derivatives with IC50 values against lysosomal α-glucosidase were selected for a CADD (computer-aided drug design) approach to identify more potent drugs. Pharmacophore modeling and atom-based 3-QSAR of 116 active compounds against lysosomal α-glucosidase were performed and identified positions and types of groups to increase activity. We performed molecular docking of 116 coumarin derivatives against the lysosomal α-glucosidase enzyme, and three compounds (isorutarine, 10_, and 36) resulted in a docking score of -7.64, -7.12, and -6.86 kcal/mol. The molecular dynamics simulation of the above three molecules and protein complex performed for 100 ns supported the interaction stability of isorutarine, 10_, and 36 with the lysosomal binding site α-glucosidase.

Coumarin-based Scaffold as α-glucosidase Inhibitory Activity: Implication for the Development of Potent Antidiabetic Agents

BACKGROUND

Delaying the absorption of glucose through α-glucosidase enzyme inhibition is one of the therapeutic approaches in the management of Type 2 diabetes, which can reduce the incidence of postprandial hyperglycemia. The existence of chronic postprandial hyperglycemia impaired the endogenous antioxidant defense by inducing oxidative stress-induced pancreatic β-cell destruction through uncontrolled generation of free radicals such as ROS, which in turn, leads to various macrovascular and microvascular complications. The currently available α -glucosidase inhibitors, for instance, acarbose, have some side effects such as hypoglycemia at higher doses, liver problems, meteorism, diarrhea, and lactic acidosis. Therefore, there is an urgent need to discover and develop potential α-glucosidase inhibitors.

OBJECTIVE

Based on suchmotifs, researchers are intrigued to search for the best scaffold that displays various biological activities. Among them, coumarin scaffold has attracted great attention. The compound and its derivatives can be isolated from various natural products and/or synthesized for the development of novel α-glucosidase inhibitors.

RESULTS

This study focused on coumarin and its derivatives as well as on their application as potent antidiabetic agents and has also concentrated on the structure-activity relationship.

CONCLUSION

This review describes the applications of coumarin-containing derivatives as α - glucosidase inhibitors based on published reports which will be useful for innovative approaches in the search for novel coumarin-based antidiabetic drugs with less toxicity and more potency.

Design and synthesis of 4,5-diphenyl-imidazol-1,2,3-triazole hybrids as new anti-diabetic agents: in vitro α-glucosidase inhibition, kinetic and docking studies

Fourteen novel 4,5-diphenyl-imidazol-1,2,3-triazole hybrids 8a-n were synthesized with good yields by performing click reaction between the 4,5-diphenyl-2-(prop-2-yn-1-ylthio)-1H-imidazole and various benzyl azides. The synthesized compounds 8a-n were evaluated against yeast α-glucosidase, and all these compounds exhibited excellent inhibitory activity (IC₅₀ values in the range of 85.6 ± 0.4-231.4 ± 1.0 μM), even much more potent than standard drug acarbose (IC₅₀ = 750.0 μM). Among them, 4,5-diphenyl-imidazol-1,2,3-triazoles possessing 2-chloro and 2-bromo-benzyl moieties (compounds 8g and 8i) demonstrated the most potent inhibitory activities toward α-glucosidase. The kinetic study of the compound 8g revealed that this compound inhibited α-glucosidase in a competitive mode. Furthermore, docking calculations of these compounds were performed to predict the interaction mode of the synthesized compounds in the active site of α-glucosidase. A novel series of 4,5-diphenyl-imidazol-1,2,3-triazole hybrids 8a-n was synthesized with good yields by performing click reaction between the 4,5-diphenyl-2-(prop-2-yn-1-ylthio)-1Himidazole and various benzyl azides. The synthesized compounds 8a-n were evaluated against yeast α-glucosidase and all these compounds exhibited excellent inhibitory activity (IC50 values in the range of 85.6 ± 0.4-231.4 ± 1.0 μM), even much more potent than standard drug acarbose (IC50 = 750.0 μM).

An efficient and targeted synthetic approach towards new highly substituted 6-amino-pyrazolo[1,5-a]pyrimidines with α-glucosidase inhibitory activity

In an attempt to find novel α-glucosidase inhibitors, an efficient, straightforward reaction to synthesize a library of fully substituted 6-amino-pyrazolo[1,5-a]pyrimidines 3 has been investigated. Heating a mixture of α-azidochalcones 1 and 3-aminopyrazoles 2 under the mild condition afforded desired compounds with a large substrate scope in good to excellent yields. All obtained products were evaluated as α-glucosidase inhibitors and exhibited excellent potency with IC₅₀ values ranging from 15.2 ± 0.4 µM to 201.3 ± 4.2 µM. Among them, compound 3d was around 50-fold more potent than acarbose (IC₅₀ = 750.0 ± 1.5 µM) as standard inhibitor. Regarding product structures, kinetic study and molecular docking were carried out for two of the most potent ones.

Meroterpene-Like α-Glucosidase Inhibitors Based on Biomimetic Reactions Starting from β-Caryophyllene

BACKGROUND

Natural meroterpenes derived from phloroglucinols and β-caryophyllene have shown high inhibitory activity against α-glucosidase or cancer cells, however, the chemical diversity of this type of skeletons in Nature is limited.

METHODS

To expand the chemical space and explore their inhibitory activities against α-glucosidase (EC 3.2.1.20), we employed β-caryophyllene and some natural moieties (4-hydroxycoumarins, lawsone or syncarpic acid) to synthesize new types of meroterpene-like skeletons. All the products (including side products) were isolated and characterized by NMR, HR-MS, and ECD.

RESULTS

In total, 17 products (representing seven scaffolds) were generated through a one-pot procedure. Most products (12 compounds) showed more potential activity (IC₅₀ < 25 μM) than the positive controls (acarbose and genistein, IC₅₀ 58.19, and 54.74 μM, respectively). Compound 7 exhibited the most potent inhibition of α-glucosidase (IC₅₀ 3.56 μM) in a mixed-type manner. The CD analysis indicated that compound 7 could bind to α-glucosidase and influence the enzyme's secondary structure.

CONCLUSIONS

Compound 7 could serve as a new type of template compound to develop α-glucosidase inhibitors. Full investigation of a biomimic reaction can be used as a concise strategy to explore diverse natural-like skeletons and search for novel lead compounds.