A Combined Experimental and Computational Study of Novel Benzotriazinone Carboxamides as Alpha-Glucosidase Inhibitors

Diabetes is a chronic metabolic disorder of the endocrine system characterized by persistent hyperglycemia appears due to the deficiency or ineffective use of insulin. The glucose level of diabetic patients increases after every meal and medically recommended drugs are used to control hyperglycemia. Alpha-glucosidase inhibitors are used as antidiabetic medicine to delay the hydrolysis of complex carbohydrates. Acarbose, miglitol, and voglibose are commercial drugs but patients suffer side effects of flatulence, bloating, diarrhea, and loss of hunger. To explore a new antidiabetic drug, a series of benzotriazinone carboxamides was synthesized and their alpha-glucosidase inhibition potentials were measured using in vitro experiments. The compounds 14k and 14l were found to be strong inhibitors compared to the standard drug acarbose with IC50 values of 27.13 ± 0.12 and 32.14 ± 0.11 μM, respectively. In silico study of 14k and 14l was carried out using molecular docking to identify the type of interactions developed between these compounds and enzyme sites. Both potent compounds 14k and 14l exhibited effective docking scores by making their interactions with selected amino acid residues. Chemical hardness and orbital energy gap values were investigated using DFT studies and results depicted affinity of 14k and 14l towards biological molecules. All computational findings were found to be in good agreement with in vitro results.

Synthesis, antioxidant, in silico and computational investigation of 2,5-dihydroxyacetophenone derived chloro-substituted hydroxychalcones, hydroxyflavanones and hydroxyflavindogenides

An imbalance between reactive oxygen species (ROS) and their elimination by antioxidants damages the cell and infect whole organism. The biological defence system against oxidative stress injury is Kelch-like ECH associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response elements (ARE) pathways. Antioxidants activate the Nrf2-ARE-Keap1 pathway and suppress the oxidative stress. Flavonoids are well known medicinal compounds inheriting antioxidant efficacy and wide spectrum of pharmacological activities. The study is aimed to synthesise, characterize and evaluate pharmacological activities of synthesized chloro-derivatives of flavonoids. Chloro-derivatives of flavonoids were synthesized and characterized by IR, ¹H NMR and ¹³C NMR. Antioxidant potential of each synthesized compound was evaluated and then subjected to molecular docking with Keap1 (PDB ID: 2FLU) for the activation of Nrf2 and computational studies were performed by using DFT approach. Among the synthesized compounds compound 1a exhibited lower IC₅₀ value. While docking and computational studies infer that compound 3c is a good Nrf2 activator and radical scavenger with highest docking score and lower energy gaps and IP values compared to references. Hence, it might be considered for further molecular studies for the treatment of inflammatory diseases through Nrf2-ARE-Keap1 pathway. Communicated by Ramaswamy H. Sarma.HighlightsChloro-substituted hydroxychalcones, hydroxyflavanones and hydroxyflavindogenides were synthesized.Antioxidant potential was accessed, compound 1a exhibited good antioxidant potential.In silico study was performed with Keap1, compound 3c have shown highest docking score with Keap1.DFT approach was used to explore the structure activity relationship.

Experimental and Computational Analysis of Newly Synthesized Benzotriazinone Sulfonamides as Alpha-Glucosidase Inhibitors

Diabetes mellitus is a chronic metabolic disorder in which the pancreas secretes insulin but the body cells do not recognize it. As a result, carbohydrate metabolism causes hyperglycemia, which may be fatal for various organs. This disease is increasing day by day and it is prevalent among people of all ages, including young adults and children. Acarbose and miglitol are famous alpha-glucosidase inhibitors but they complicate patients with the problems of flatulence, pain, bloating, diarrhea, and loss of appetite. To overcome these challenges, it is crucial to discover new anti-diabetic drugs with minimal side effects. For this purpose, benzotriazinone sulfonamides were synthesized and their structures were characterized by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopy. In vitro alpha-glucosidase inhibition studies of all synthesized hybrids were conducted using the spectrophotometric method. The synthesized compounds revealed moderate-to-good inhibition activity; in particular, nitro derivatives 12e and 12f were found to be the most effective inhibitors against this enzyme, with IC₅₀ values of 32.37 ± 0.15 µM and 37.75 ± 0.11 µM. In silico studies, including molecular docking as well as DFT analysis, also strengthened the experimental findings. Both leading compounds 12e and 12f showed strong hydrogen bonding interactions within the enzyme cavity. DFT studies also reinforced the strong binding interactions of these derivatives with biological molecules due to their lowest chemical hardness values and lowest orbital energy gap values.

Synthesis of imidazole-pyrazole conjugates bearing aryl spacer and exploring their enzyme inhibition potentials

Developing improved enzyme inhibitors is an effective therapy to counter various diseases. Aiming to build up biologically active templates, a new series of bis-diazoles conjugated with an aryl linker was designed and prepared through a convenient synthetic approach. Synthesized derivatives 6(a-m), having different substitutions at the 2^nd position of the imidazole nucleus, depict the scope of present study. These compounds were characterized through spectroscopic methods and further examined for their in vitro enzyme inhibitory potentials against two selected enzymes: α-glucosidase and lipoxygenase (LOX). Overall, this series was found to be effective against α-glucosidase and moderately active against LOX enzyme. Compound 6k was the most potent α-glucosidase inhibitor with IC₅₀ = 54.25 ± 0.67 µM as compared to reference drug acarbose (IC₅₀ = 375.82 ± 1.76 µM). The docked conformation revealed the involvement of substituent's heteroatoms with amino acid residue Gly280 through hydrogen bonding. The most active LOX inhibitor was 6a with IC₅₀ = 41.75 ± 0.04 µM as compared to standard baicalein (IC₅₀ = 22.4 ± 1.3 µM). Docking model of 6a suggested the strong interaction of imidazole's nitrogen with iron atom of the active pocket of enzyme. Other features like lipophilicity, bulkiness of compounds, pi-pi interactions and/or pi-alkyl interactions also affected the inhibiting potentials of all prepared scaffolds.

Synthesis, characterization and applications of poly-aliphatic amine dendrimers and dendrons

In the current era, the dendrimers have vast potential applications in the area of electronics, healthcare, pharmaceuticals, biotechnology, engineering products, photonics, drug delivery, catalysis, electronic devices, nanotechnologies and environmental issues. This review recaps the synthesis, characterization and applications of poly-aliphatic amine dendrimers.

Synthesis and optical studies of Y-shaped imidazole derivatives

A novel series Y-shaped π-expanded imidazole based chromophores was designed and synthesized. The series contains thirteen 2-aryl-4,5-bis[2-(aryl)vinyl)]-1H-imidazoles (6a-6m), which were characterized by spectroscopic analysis. The structures of compounds 6d and 6j were also confirmed by X-ray crystallographic analysis. The optical studies were investigated using absorption and emission measurements in dichloromethane. The fluorescence quantum yields were observed varying in 0.22-0.59 range, but the compounds with nitro substituent did not show the fluorescence. The absorption and emission study of the series helped us to understand the effect of substituents on the optical properties of compounds as well.

Synthesis of 3-Arylindazole-1-acetic Acids and In Vitro Study of Potential Antibacterial Effect

Background:

Indazoleacetic acids and their pharmaceutically acceptable salts have been claimed to be useful as anti-inflammatory, analgesic and antipyretic agents. They are active in the treatment of respiratory diseases such as asthma, bronchitis, allergies and obstructive pulmonary diseases. </P><P> Objectives: We report herein a feasible study concerned about the design, synthesis, structure and in vitro antimicrobial activity of 3-arylindazole-1-acetic acids derivatives. Series of compounds were synthesized by alkylation of 3-arylindazoles.

Method:

Synthesized compounds were subjected to study the effect on microbial growth in vitro. All synthesized compounds were found to exhibit antibacterial activities against a range of grampositive (Bacillus subtilis, Staphylococcus aureus) and gram-negative bacteria (Shigella sonnei, Escherichia coli) by broth dilution method.

Results:

The synthesized compounds exhibited antibacterial activities comparable to fluoroquinolones and some compounds exhibited better activity. These findings suggest a great potential of 3-arylindazole-1-acetic acids as antibacterial compounds.

Conclusion:

3-Arylindazole-1-acetic acids are potent antimicrobial agent better than their respective 3-arylindazoles that revealed moderate activity against both gram positive and gram negative bacteria.

Anti-HIV activity of new pyrazolobenzothiazine 5,5-dioxide-based acetohydrazides

A series of fifteen new 2-[3-(3-chlorophenyl)-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-4(2H)-yl]-N'-arylmethyleneacetohydrazides (5a-o) were synthesized and screened for their anti-HIV-1 and cytotoxicity activity. Out of fifteen pyrazolobenzothiazine-based hydrazones, thirteen were found to be active inhibitors of HIV with EC50 values <20 μM. Moreover, the cytotoxicity results showed that most of the compounds were toxic to PBM, CEM and Vero cell lines. This information could be used for structural modifications to acquire good candidates of HIV drugs.

Crystal structure of 3,4-di-chloro-anilinium hydrogen phthalate

In the title salt, C₆H₆Cl₂N⁺·C₈H₅O₄⁻, the carb­oxy­lic acid and carboxyl­ate groups of the anion form dihedral angles of 20.79 (19) and 74.76 (14)°, respectively, with the plane of the benzene ring. In the crystal, mol­ecules are assembled into a two-dimensional polymeric network parallel to (100) via N—H⋯O and O—H⋯O hydrogen bonds. In addition, within the layer, there are π–π stacking inter­actions between the benzene rings of the cation and the anion [centroid–centroid distance = 3.6794 (17) Å]. A weak C—H⋯O interaction is also observed.

Crystal structure of 4-chloro-2-{(E)-[(3,4-dimethylphenyl)imino]methyl}phenol

In the title compound, C₁₅H₁₄ClNO, which is isostructural with its bromo analogue [Tahir et al. (2012 ▸). Acta Cryst., E68, o2730], the dihedral angle between the planes of the aromatic rings is 2.71 (7)° and an intra­molecular O—H⋯N hydrogen bond closes an S(6) ring. In the crystal, extremely weak C—H⋯π inter­actions link the mol­ecules into a three-dimensional network.

Crystal structure of (4Z)-4-[(2E)-3-(4-chloro-phen-yl)-1-hy-droxy-prop-2-en-1-yl-idene]-5-methyl-2-phenyl-1H-pyrazol-5(4H)-one

In the the asymmetric unit of the title compound, C₁₉H₁₅ClN₂O₂, there are two symmetry-independent mol­ecules, which adopt similar conformations. The largest difference is observed in the dihedral angles between the phenyl and the pyrazole fragments [17.00 (12) and 23.42 (10)°]. A strong intra­molecular O—H⋯O hydrogen bond with the S (6) motif is observed in both mol­ecules. Pairs of π–π stacking inter­actions between the phenyl groups [centroid–centroid distances = 3.6627 (13) and 3.7156 (14) Å] assemble the mol­ecules into two types of centrosymmetric dimers. Weak C—H⋯O inter­actions connect mol­ecules into chains along the b axis.

Crystal structure of (4Z)-4-[(2E)-1-hydroxy-3-(naphthalen-2-yl)prop-2-en-1-yl-idene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one

In the title compound, C23H18N2O2, the pyrazole ring subtends dihedral angles of 2.01 (13) and 1.55 (10)° with the pendant benzene ring and the naphthalene ring system, respectively. The mol-ecule is almost planar (r.m.s. deviation for the 27 non-H atoms = 0.025 Å) and intra-molecular O-H⋯O and C-H⋯O hydrogen bonds both close S(6) loops. In the crystal, very weak aromatic π-π stacking inter-actions between the benzene and the pyrazole rings, with centroid-centroid distances of 3.8913 (14) and 3.9285 (15) Å, are observed.

Crystal structure of (4E)-4-(8-meth-oxy-2H-chromen-2-yl-idene)-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one

In the title compound, C20H16N2O3, the phenyl substituent attached to the pyrazole ring makes a dihedral angle of 4.87 (7)° with the rest of the mol-ecule. In the crystal, mol-ecules are connected into inversion dimers of the R 2 (2)(14) type by pairs of C-H⋯O inter-actions. π-π inter-actions exist between the benzene and pyrazole rings at a distance of 3.701 (1) Å. Similarly, π-π inter-actions are present at a centroid-centroid distance of 3.601 (1) Å between the oxygen-containing heterocyclic ring and meth-oxy substituted aromatic ring of a neighbouring mol-ecule. Additional C-H⋯π and C=O⋯π inter-actions are also observed.

Crystal structure of (4Z)-4-[(2E)-3-(2-chloro-phen-yl)-1-hy-droxy-prop-2-en-1-yl-idene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one

In the title compound, C₁₉H₁₅ClN₂O₂, the pyrazole ring is almost planar (r.m.s. deviation = 0.002 Å) and subtends dihedral angles of 5.31 (16) and 1.86 (16)° with the phenyl and chloro­benzene rings, respectively. An intra­molecular O—H⋯O hydrogen bond closes an S(6) ring and a short C—H⋯O contact is also observed. In the crystal, mol­ecules are linked by weak C—H⋯O inter­actions to generate (001) sheets. Weak aromatic π–π inter­actions between the chloro­benzene and pyrazole rings, with a centroid–centroid distance of 3.7956 (17) Å are also observed.

Crystal structure of 3-(3,4-di-methyl-anilino)-2-benzo-furan-1(3H)-one

In the title compound, C₁₆H₁₅NO₂, the 2-benzo­furan-1(3H)-one and 3,4-di­methyl­aniline fragments are oriented with a dihedral angle of 89.12 (5)°. N—H⋯O hydrogen-bond inter­actions join mol­ecules into C(6) chains propagating along the a axis. In addition, there are π–π stacking inter­actions between the 2-benzo­furan­one benzene rings [centroid–centroid dis­tance = 3.7870 (13) Å] and C—H⋯π inter­actions between one of the methyl groups and the 3,4-di­methyl­aniline benzene ring.

1-{[(E)-(4-{[(2Z)-2,3-Dihydro-1,3-thiazol-2-ylidene]sulfamoyl}phenyl)iminiumyl]methyl}naphthalen-2-olate

In the title zwitterionic compound, C₂₀H₁₅N₃O₃S₂, the 2-hy­droxy­naphthalene-1-carbaldehyde group A, the anilinic unit B and the 1,3-thia­zol-2(3H)-imine group C are each approximately planar with r.m.s. deviation of 0.0721, 0.0412 and 0.0125 Å, respectively. The dihedral angles between A/B, A/C and B/C are 24.70 (10), 79.97 (7) and 83.14 (6)°, respectively. There is an intra­molecular S(6) motif involving the imine N—H and the naphtho­late O atom. In the crystal, inversion-related mol­ecules form dimers as a result of N—H⋯N and N—H⋯O hydrogen bonds with R₂²(8) and R₁²(4) motifs, respectively. Weak π–π inter­actions between the benzene and naphthyl rings of inversion-related mol­ecules have ring centroid–centroid distances of 3.638 (2) and 4.041 (2) Å. A C—H⋯π inter­action occurs between the thia­zol ring and the benzene ring of an adjacent mol­ecule.

Potential antibacterial activity of coumarin and coumarin-3-acetic acid derivatives

Coumarin and coumarin-3-acetic acid derivatives were synthesized by reacting phenols with malic acid, ethyl acetoacetate and ethyl acetylsuccinate in appropriate reaction conditions. All synthesized compounds were subjected to test for their antimicrobial activities against variety of gram positive (Bacillus subtilis, Staphylococcus aureus) and gram negative bacterial stains (Shigella sonnei, Escherichia coli) by agar dilution method. Several of them exhibited appreciable good antibacterial activity against the different strains of gram positive and gram negative bacteria. These findings suggest a great potential of these compounds for screening and use as antibacterial agents for further studies with a battery of bacteria.

Cholinesterase Inhibitory Activities of N-Phenylthiazol-2-Amine Derivatives and their Molecular Docking Studies

Alzheimer's disease (AD) is a type of neurodegenerative disorder which is responsible for many cognitive dysfunctions. According to the most accepted cholinergic hypothesis, cholinesterases have a major role in AD symptoms. The use of small molecules as inhibitors is one of the most useful strategies to control AD. In the present work, a series of N-phenylthiazol-2-amine derivatives was screened against acetylcholinesterase (AChE) from Electrophorus electricus and butyrylcholinesterase (BChE) from horse serum by using Ellman's method, using neostigmine and donepezil as reference drugs. Some of the assayed compounds proved to be potent inhibitors for AChE and BChE activity. N-(2,3-dimethylphenyl)thiazol-2-amine, 3j was found to be the most active inhibitor among the series with IC50 value of 0.009 ± 0.002 µM and 0.646 ± 0.012 µM against AChE and BChE, respectively. Molecular docking studies were carried out in order to better understand the ligand binding site interactions.

Synthesis of novel indenoquinoxaline derivatives as potent α-glucosidase inhibitors

A series of new N-(11H-Indeno[1,2-b]quinoxalin-11-ylidene)benzohydrazide derivatives (3a-3p) were synthesized and evaluated for their α-glucosidase inhibitory activity. The synthesized compounds 3d, 3f, 3g, 3k, 3n, 3p and 4 showed significant α-glucosidase inhibitory activity as compared to acrabose, a standard drug used to treat type II diabetes. Structures of the synthesized compounds were determined by using FT-IR, (1)H NMR, (13)C NMR, mass spectrometry and elemental analysis techniques.