Publications by authors named "Sumeer Ahmed"

Aim: There is an urgent need for new antimicrobial compounds with alternative modes of action for the treatment of drug-resistant bacterial and fungal pathogens.

Background: Carbohydrates and their derivatives are essential for biochemical and medicinal research because of their efficacy in the synthesis of biologically active drugs.

Objective: In the present study, a series of methyl α-D-mannopyranoside (MMP) derivatives (2-6) were prepared via direct acylation, and their biological properties were characterized.

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This synthetic organic methodology involves the creation of novel coumarin-based hybrids of series (1-4) with pyrazole ring and (5-8) with oxadiazole moiety. The targeted compounds were tested for In vitro Antimicrobial efficacy against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans pathogenic microbes using disc diffusion and broth microdilution with ciprofloxacin and fluconazole as reference standards. Density functional theory (DFT) studies were used to study atomic structure and reactivity, including absolute electronegativity (χ), electrophilicity (ω), electron acceptor (ω+), donor capabilities (ω-), electron affinity (EA), energy gap (ΔE), global hardness (η), global softness (S), and ionisation potential (IP) and FMOs, NBOs, MEP, and Mulliken Charge analysis.

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Introduction: In the present work, a series of novel pyridine carboxamides 3(a-h) were synthesized and screened with antibacterial activity. This research explores the application of Density Functional Theory (DFT) in studying biological systems at the quantum mechanical level, particularly in the context of drug design. DFT offers a streamlined approach to quantum mechanical calculations, making it indispensable in various scientific fields, and for its exceptional accuracy, reduced computational time, and cost-effectiveness has become a pivotal tool in computational chemistry.

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Nucleoside derivatives are important therapeutic drugs that have drawn significant attention recently. In this study, cytidine () was first exposed to react with cinnamoyl chloride in ,-dimethylformamide, and trimethylamine to obtain 5'--(cinnamoyl)cytidine, which was further treated with several acylating agents to obtain a series of 2',3'-di--acyl derivatives. The chemical structures of the synthesized compounds were established through spectral, analytical, and physicochemical techniques.

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In this study, a series of thiazolidine-2,4-dione derivatives were synthesized and evaluated for antibacterial activity against Gram-positive and Gram-negative strains of , and . Newly prepared thiazolidine (TZD) derivatives were further screened separately for antifungal activity against cultures of fungal species, namely, , , and . The electron-donating substituents (-OH and -OCH) and electron-withdrawing substituents (-Cl and -NO) on the attached arylidene moieties of five-membered heterocyclic ring enhanced the broad spectrum of antimicrobial and antifungal activities.

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A series of new heteroleptic oxovanadium(IV) complexes with the general formula [VOL(Dcf)] (), where L = thiosemicarbazone (TSC)-based ligands and Dcf = diclofenac have been synthesized and characterized. The spectral studies along with the density functional theory calculations evidenced the distorted square-pyramidal geometry around oxovanadium(IV) ion through imine nitrogen and thione sulfur atoms of TSC moiety, and two asymmetric carboxylate oxygen atoms of diclofenac drug. The complexes were evaluated for antioxidant activity using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (HO) and superoxide radical scavenging assays with respect to the standard antioxidant drugs butylated hydroxyanisole (BHA) and rutin.

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Twelve new heteroleptic nickel(II) and copper(II) complexes of the type [M(L )(Pfx) ] (1-12), where L =2-benzylidenehydrazinecarbothioamide (L ), 2-benzylidene-N-methylhydrazinecarbothioamide (L ), 2-benzylidene-N-phenylhydrazinecarbothioamide (L ), 2-(4-methylbenzylidene)hydrazinecarbothioamide (L ), 2-(4-methylbenzylidene)-N-methylhydrazinecarbothioamide (L ) and 2-(4-methylbenzylidene)-N-phenylhydrazinecarbothioamide (L ), Pfx=pefloxacin and M=Ni(II) or Cu(II) have been synthesised, and their structures were confirmed by different spectral techniques. The spectral data and density functional theory (DFT) calculations supported the bonding of pefloxacin drug molecule via one of the carboxylate oxygen atoms and the pyridone oxygen atom, and the thiosemicarbazone ligand via the imine nitrogen and the thione sulfur atoms with the metal(II) ion, forming distorted octahedral geometry. In vitro antiproliferative activity of the synthesized complexes was evaluated against three human breast cancer (T47D, estrogen negative (MDA-MB-231) and estrogen positive (MCF-7)) as well as non-tumorigenic human breast epithelial (MCF-10a) cell lines, which showed the higher activity for the copper(II) complexes.

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In this work, Schiff bases and Thiazolidin-4-ones, were synthesized using Sonication and Microwave techniques, respectively. The Schiff base derivatives () were synthesized the reaction of Sulfathiazole () with benzaldehyde derivatives (), followed by the synthesis of 4-thiazoledinone () derivatives by cyclizing the synthesized Schiff bases through thioglycholic acid. All the synthesized compounds were characterized by spectroscopic techniques such as FT IR, NMR and HRMS.

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Objectives: The present research focuses on the in vitro anti-proliferative, and in silico ribonucleotide reductase and pharmacokinetics studies of twelve heteroleptic metal complexes of the general formulae [Ag(L)(ibu)] (1-4) and [M(L)(ibu)] (5-12), where L = 2-(1-(4-substitutedphenyl)ethylidene)-N-methylhydrazinecarbothioamide, ibu = non-steroidal anti-inflammatory drug (ibuprofen), and M = Cu(II) and Ni(II).

Methods: Various spectroscopic techniques were used to authenticate the structure of the synthesized complexes. UV-Vis and cyclic voltammetry techniques were used to analyse the stability and the reducing ability of the complexes.

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