Schiff Base Derivatives Research Articles

Synthesis of Sulfonamide-Based Schiff Bases as Potent Anticancer Agents: Spectral Analyses, Biological Activity, Molecular Docking, ADME, DFT, and Pharmacophore Modelling Studies.

The current study focuses on the synthesis and characterization of six benzenesulfonamide-based Schiff base derivatives (7-12) with various electron-withdrawing and electron-donating substituents (-F, -CI, -Br, -CH3, and -OCH3) and the assessment of their antiproliferative activities against human lung (A549) and liver (HepG2) cancer cell lines using in vitro and in silico approaches. The structures of the synthesized compounds (7-12) were elucidated by elemental analysis and FT-IR, 1D (1H, 13C, APT, and DEPT-135), and 2D (HMQC and HMBC) NMR spectroscopies. The cytotoxic activities of the targeted compounds were determined at various concentrations against these cancer cell lines for 72 h, using the MTT method. The targeted molecules (7-12) demonstrated remarkable antiproliferative activities, with IC50 values ranging from 6.032-9.533 μM against the A549 cell line and 5.244-9.629 μM against the HepG2 cell line. These compounds showed activities at lower or very similar concentrations to cisplatin against the A549 cell line and at much lower concentrations than cisplatin against the HepG2 cell line. Among them, compounds 10 and 12 were found to be more effective against A549 and HepG2 cells, respectively, than cisplatin. These compounds were analyzed by interacting with the 1BNA, 4HJO, and 4ASD crystal structures in molecular docking studies.

Synthesis, characterization and antibacterial activity of hexasubstituted Coumarin-based Schiff base derivative of cyclophosphazene

This study focuses on synthesis and characterization of hexa-substituted coumarin based Schiff base derivative of cyclotriphosphazene (Compound 3). The antibacterial activity of Compound 3 was evaluated against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa), and Klebsiella pneumoniae (K. pneumoniae) bacterial strains using minimum inhibitory concentration (MIC) and percentage-killing method. Compound 3 exhibited a lower MIC of 300 μg/mL against S. aureus than 500 μg/mL for P. aeruginosa and K. pneumoniae, indicating greater efficacy against Gram-positive bacteria. Percentage-killing data confirmed Compound 3 significant bactericidal activity against S. aureus across concentrations ranging from 100 to 500 μg/mL, comparable to ampicillin. In contrast, its efficacy against Gram-negative strains was lower, suggesting a more selective spectrum of activity. These findings suggest that Compound 3 shows promise as a potential antibacterial agent with preferential activity against Gram-positive bacteria, warranting further investigation into its mechanism of action and therapeutic potential.

In silico studies, synthesis, characterization and in vitro studies of levosulpiride derivatives.

Aim: Breast cancer is the most recurring cancer among females and is being diagnosed as a major cause of death among women.Materials & methods: Levosulpiride Schiff base derivatives were synthesized and analyzed by physical and spectral (FTIR, 1H-NMR, 13C-NMR) analysis. MTT assay against MCF-7 (human breast cancer cell line), scavenging activity and Molecular docking against receptors 1M17, 3PP0, 3IOK and 4KIK along ADME pharmacokinetic studies were performed.Results & conclusion: L1 and L3 synthesized derivatives have revealed better percent cell viability and inhibitory concentration (IC50) with scavenging activity as of the parent compound. L1, L3 and L9 revealed significant docking scores compared with standard drugs. Most of the derivatives showed strong pharmacokinetic profiles while no drug crossed blood-brain barrier. The newly synthesized L1 and L3 levosulpiride-derived compounds have demonstrated promising anticancer properties against breast cancer cells.

Utilization of Schiff base ligands to chelate Ag+ for highly specific and sensitive Hg2+/Ag+ immunoassay

In this study, a planar benzothiazole Schiff base derivative ZX1 was designed and synthesized to selectively precipitate silver ions, in conjunction with the immunoassay detection of Hg2+ ions. The silver chelation process was highly effective in the pH range of 7–10, with a silver ion precipitation ratio of 99.9 %. The coordination behavior of ZX1 with Ag+ was studied using a series of spectroscopic measurements, topography analysis and DFT calculation. The shortest bond distances were 2.251 and 2.254 Å between nitrogen atom of thiazole and Ag+. Weak interactions were analyzed using the interaction region indicator (IRI) method and VMD. The immunoassay was developed through an anti-Hg2+/Ag+ monoclonal antibody, which showed similar sensitivities for Ag+ and Hg2+. The selectivity and anti-interference ability of the Schiff base ligands were tested for some hard metal ions and several anions. With co-existence of interference ion Ag+, Hg2+ was detected in rice matrix solution with 77 %∼123.5 % recovery by addition of ZX1 as the masking reagent and 90.3 %∼115 % for wheat matrix. This research provides a promising immunoassay strategy for simultaneous detection of silver ions and mercury ions in food matrix by utilization of Schiff base ligands. This novel Schiff base ligand was then used as the pre-treatment reagent to remove silver ions within 5 min for detection of Hg2+ or detection of both Ag+ and Hg2+ based on a novel bi-specific heavy metal antibody.

Design, Synthesis, and Study of Novel Memantine Schiff Base Derivatives Against Targeted Enzymes in Alzheimer’s Disease

Introduction: According to WHO, Alzheimer’s disease was estimated at 74.4 million cases in 2023, which will increase by 152.8 million cases in 2050. The therapeutic options available in the market for the treatment of AD are only capable of reducing the symptoms of dementia but not preventing progressive degeneration. Memantine is a non-competitive NMDAR antagonist used for the treatment of patients with moderate-to-severe AD, but it has a high toxicity profile. To counter this, the Memantine Schiff base derivatives were designed as simple and lowtoxicity compounds. Materials and Methods: Molecular docking was performed against the targeted enzymes Acetylcholinesterase and Butyrylcholinesterase using AUTODOCK 1.5.7 software. A series of novel Memantine derivatives of Schiff base were synthesized by condensing Memantine with various aryl aldehydes and screened for their invitro-cholinesterase inhibitory activity towards Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) by Ellman’s method. Results and Discussion: Among the designed compounds, compounds LMV and LMC showed maximum binding scores of -10.35 kcal/mol and -10.12 kcal/mol, respectively, than the standard Donepezil (-8.78 kcal/mol) against Acetylcholinesterase. The compounds LMONB and LMDMB produced significant binding scores of -9.31 kcal/mol and -9.11 kcal/mol, respectively, compared to the standard Donepezil (-7.57 kcal/mol) against Butyrylcholinesterase. Also, compounds LMV (30.9 ± 2.13 μM) and LMDMB (13.51 ± 1.12 μM) showed potent inhibitory activity against the AChE and BChE. These compounds possess drug-like characteristics and are also capable of crossing the Blood Brain Barrier (BBB). Conclusion: The studied compounds LMV and LMDMB, being non-toxic, obey Lipinski’s rule of 5 and are potential inhibitors against targeted enzymes, which may be promising clinical candidates for treating Alzheimer’s disease.

A versatile inhibitory approach and molecular mechanism on cancer cells and cholinesterase enzymes: Synthesis, DFT, ADMET and molecular docking of thiadiazole and oxadiazole derivatives

This study presents a multi-routed research design featuring thiadiazole/ oxadiazole based Schiff base derivatives as potential inhibitors, targeting cancer and Alzheimer. Among thiadiazole based Schiff base derivatives, the excellent inhibition was exhibited by compound 1 (IC50 = 20.10 ± 1.1, 22.21 ± 1.03 and 26.23 ± 2.2 µM for HepG2 (liver cancer), MCF-7 (breast cancer) and W138 (lung cancer), respectively) in comparison to the standard Doxorubicin. Oxadiazole based compound 9 was also found with spellbinding efficacy (IC50 =15.20 ± 2.5, 19.13 ± 2.2 and 12.33 ± 3.4 µM for HepG2, MCF-7 and W138, respectively). Both compounds 1(IC50=3.10 ± 0.20 and 3.70 ± 0.10 µM against AChE and BuChE) and 9 (IC50=2.20 ± 0.10 and 2.80 ± 0.50 µM against AChE and BuChE) were also found as excellent anti-Alzheimer agents in comparison to reference donepezil. The outcomes of in vitro biological activity were further studied in silico via molecular docking, DFT and ADMET to elucidate the binding interactions, stability, reactivity and pharmacokinetic profiles of potent compounds.

Synthesis and characterization of some new Schiff base azo disperse dyes based on chromene moiety for simultaneous dyeing and antimicrobial finishing

New azo Schiff base disperse dyes based on a chromene moiety were synthesized by reacting (2-amino-7-hydroxy-4-(4-methoxyphenyl)-4 H-chromene-3 carbonitrile) and(2-amino-4-(3,4-dimethoxyphenyl)-7-hydroxy-4 H-chromene-3-carbonitrile), with vanillin and ninhydrin, producing new chromene Schiff base derivatives, which in turn were coupled with 2-chloro-4-nitroaniline diazonium salt to give new 4 azo disperse dyes (1–4). The structures of the prepared dyes were confirmed using elemental analysis, 1HNMR spectroscopy, mass spectrometry, and IR. The synthesized dyes were applied to polyester and nylon fabrics using different dyeing techniques: high temperature- high pressure, and ultrasonic dyeing methods. The highest K/S values for all investigated dyes were achieved usinga high temperature-high pressure dyeing technique. Also, the color reflectance of all synthesized dyes with different dyeing shades (1%, 2%, and 3%) was obtained. The fastness properties of the dyed samples using the investigated dyes showed good color fastness toward light, washing, rubbing, and perspiration fastness. The presence of a chromene moiety and Schiff base in the investigated dyes promotes a higher antimicrobial activity on nylon and polyester fabrics against all tested bacteria (E. coli gram-negative and Staphylococcus aureus gram-positive) and two fungi, Aspergillus Niger and Candida albicans.

Synthesis, Anti-inflammatory and in silico Studies of few novel 1,2,4-Triazole Derived Schiff Base Compounds

Synthesis, Anti-inflammatory and in silico Studies of few novel 1,2,4-Triazole Derived Schiff Base Compounds

Synthesis of new multi-functionalized Schiff base derivatives based on vanillic acid: Antimicrobial activity, photophysical, DFT calculations and in-silico study

The paper reports the synthesis of novel multi-functional Schiff base derivatives (S1-S7) via Steglich esterification, thoroughly characterized by standard spectroscopic methods (1H NMR, 13C NMR, FT-IR and Mass spectrometry) and elemental analysis technique. Density Functional Theory calculations (including FMOs’, MEP, IR and UV–Visible), photophysical, molecular docking simulations, and in-vitro antimicrobial assays were employed to study the structure and reactivity of synthesized compounds. The study highlights significant antimicrobial activity of certain derivatives, which aligns with computational predictions. UV–Visible study identifies various transitions like π→π*, n→π* occurring in the system aligning with the theoretical absorption spectra. Biological studies reveal that compounds S1, S2 and S5 exhibit significant potency for antimicrobial investigation correlating with the computational study. Further, the calculated HOMO-LUMO band gap for S1-S7 molecules (3.29 eV) suggest their insulating nature. Notably, MEP study shows negative electrostatic potential near nitro group and the positive potential near alkyl groups indicating preferable site for electrophilic and nucleophilic attack, respectively. Moreover, molecular docking was implemented to computationally screen the multi-functionalized Schiff base along with molecular dynamics simulation including MM-PBSA energy calculation in order to discover the reasonable physiological significance ensuring stability of binding interactions of relevant molecules.

Effects of flavonoids on yeast ABC transporters activity

Flavonoids are known to be effective biomodulators of various processes in eukaryotic cells. As these compounds are present in wine and beer raw materials, they can influence the qualitative characteristics of the ethanol content in wine-making and brewing products, including directly through the mechanisms of regulation of gene expression and the activity of ATP-binding cassette (ABC) proteins. The main function of ABC transporters in yeast cells is to transport various substrates, including ethanol. This process ensures the survival of yeast cells under conditions of ethanol stress. It has been found that flavonoids, as well as their Schiff base derivatives, are effective stimulators and inhibitors of mRNA expression and activity of ABC proteins both in logarithmic and stationary phases of growth, which has a direct impact on bioethanol production by yeast.

Furan-Triazine clubbed Schiff base derivatives: Computational insight and empirical precision against A-549 and MDA-MB-468 Carcinoma cells

The purpose of this effort is to generate a range of 1,3,5-triazine substituted furan-2-carbaldehyde Schiff base derivatives (5a-5h) that may be employed as anticancer drugs. The effectiveness of recently synthesised compounds was evaluated in vitro against A-549 lung cancer cell line and MDA-MB-468 breast carcinoma cell line, providing an in-depth evaluation of their possible therapeutic effect on these particular cancer types. Compounds 5e and 5g were found to be the most effective of this series in targeting A-549 lungs cancer cells with IC50 values of 6.33 and 0.31 μM, respectively against the standard drug pictilisib (IC50 1.66 μM), while compounds 5a and 5e were found to be the most promising in targeting MDA-MB-468, with IC50 values of 3.97 and 6.38 μM, respectively, against pictilisib (IC50 3.60 μM). To understand their interaction with the essential proteins involved in the progression of cancer, molecular docking studies were carried out, which gave information about their putative mechanisms of action. Furthermore, molecular dynamics simulations were utilised to analyse the stability and dynamic behaviour of the most active compounds inside the protein binding sites. The study revealed several compounds demonstrating notable anticancer activity, offering encouraging possibilities for their continued development and improvement as novel anticancer medications.

A Captivating Potential of Schiff Bases Derivatives for Antidiabetic Activity.

A double bond between the nitrogen and carbon atoms characterizes a wide class of compounds known as Schiff bases. The flexibility of Schiff bases is formed from several methods and may be combined with alkyl or aryl substituents. The group is a part of organic compounds, either synthetic or natural, and it serves as a precursor and an intermediate in drugs that have therapeutic action. The review focuses on molecular docking and structure-activity relationship (SAR) analysisfor antidiabetic effects of the different non-metal Schiff bases. Many studies have found that Schiff bases are used as linkers in an extensive range of synthesized compounds and other activities. Thus, this current study aims to give the scientific community a thoughtful look at the principal ideas put forward by investigators regarding antidiabetic actions exhibited by certain Schiff-based derivatives, as this review covered many aspects, including docking and SAR analysis. For individuals who intend to create novel antidiabetic compounds with Schiff bases as pharmacophores or physiologically active moieties, it will be an invaluable informational resource.

Novel Schiff base decorated cyclotriphosphazene chemosensors for Fe and Cu ions detection

In this study, new 2-aminobenzothiazole derivative Schiff base decorated cyclotriphosphazene compounds (SBCTP 1 and 2), which are likely to have chemical sensor properties, were designed and synthesized successfully. The compounds were structurally characterized by mass analysis and NMR (1H, 13C and 31P) spectroscopies. Photophysical and chemosensory properties of SBCTP 1 and 2 against some analytes were examined by UV–vis and Fluorescence spectrophotometry. While a significant increase was observed in the UV–vis absorption signals observed at 350 nm with the addition of Fe3+ and Fe2+ ions and a new absorption band was observed at 290 nm with the addition of Cu2+. In addition, according to Job's plot obtained from UV–vis absorption titrations, the complex stoichiometries of SBCTP 1 and 2 with selective analytes were determined as 1:1 (L/M) and 1:2 (L/M), respectively. The selective interaction of donor atoms on SBCTP 1 and 2 with Cu2+, Fe2+ and Fe3+ ions give these compounds chemosensory properties. This study showed that the synthesized Schiff base decorated cyclotriphosphazene compounds (SBCTP 1 and 2) could be new chemosensors with high selective and immediate sensitivity for the detection of iron and copper ions.

Correction: Substituted furan-carboxamide and Schiff base derivatives as potential hypolipidemic compounds: evaluation in Triton WR-1339 hyperlipidemic rat model

Correction: Substituted furan-carboxamide and Schiff base derivatives as potential hypolipidemic compounds: evaluation in Triton WR-1339 hyperlipidemic rat model

Synthesis, in vitro and in silico study of novel 1,3-diphenylurea derived Schiff bases as competitive α-glucosidase inhibitors.

Diabetes mellitus has become a major global health burden because of several related consequences, including heart disease, retinopathy, cataracts, metabolic syndrome, collapsed renal function, and blindness. In the recent study, thirty Schiff base derivatives of 1,3-diphenylurea were synthesized and their anti-diabetic activity was evaluated by targeting α-glucosidase. The compounds exhibited an overwhelming inhibitory potential for α-glucosidase with higher potency ranging from 2.49-37.16 μM. The most effective compound, 5h, showed competitive inhibition of α-glucosidase (K i = 3.96 ± 0.0048 μM) in the kinetic analysis and strong binding interactions with key residues α-glucosidase in docking analysis, indicating its potential for better glycemic control in diabetes patients.

Insights into the role of potent thiadiazole based Schiff base derivatives in targeting type-II diabetes: A combine in-vitro and in-silico approaches

A novel series of varied substituted thiadiazole based Schiff base analogues (1–21) were designed and characterized using NMR (13C, 1H) and HREI-mass spectrometry, and secerned against the enzymes responsible for hyperglycemia i-e α-amylase and α-glucosidase. Newly designed analogues demonstrated distinct inhibitory activities having IC50= 1.10 ± 0.50 to 21.40 ± 0.20 µM (for alpha-amylase) and 2.50 ± 0.05 to 21.40 ± 0.10 µM (for alpha-glucosidase) in contrast to acarbose a well-known marketed drug (IC50 = 3.16 ± 0.22 & 4.8 ± 0.21 µM for α-amylase and α-glucosidase, respectively). Compound (20) with tri-fluoromethyl at para position of aromatic ring revealed as lead candidate among the members of synthesized series, having effective inhibitory activity against enzymes α-amylase and α-glucosidase. The excellent activity of compound (20) might be due to involvement of fluoro atom interacting via H-bonding with the active sites of enzymes α-amylase and α-glucosidase being targeted. Furthermore, for exploration of binding interactions of potent drugs, molecular docking was performed. For investigation of drug likeness and toxicity, ADME analysis was also conducted.

Biological study with molecular mechanism of imidazothiazole based Schiff bases as anti-Alzheimer agent: Insight into the role of synthesis, molecular docking and ADMET analysis

The current study aims to develop synthetic route and biological evaluation regarding a series of fused imidazothiazole derived Schiff base hybrid derivatives (1–17), synthesized by treating imidazothiazole bearing ester with hydrazine. The first intermediate imidazothiazole bearing hydrazide upon treating with ammonium thiocyanate was cyclized in the presence of 1,2-dioxane and potassium carbonate to second intermediate fused imidazothiazole bearing 2-aminothiadiazole. This intermediate was then mixed substituted benzaldehyde to afford fused imidazothiazole derived Schiff base hybrid derivatives. The current study revealed that the synthesized derivatives were examined and found with high inhibition profile against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in-comparison with marketed drug donepezil (IC50=7.20 ± 0.10 and 7.80 ± 0.20 µM for AChE and BuChE). Among all the derivatives, analog 11 (IC50=2.10 ± 0.30 and 2.80 ± 0.20 µM) was the one having highest inhibitory profile against both enzymes due to attachment of highly active tri-fluoromethyl group and hence regarded as potent analog. Furthermore, analog 7, 8, 9, 12 and 14 were also studied to exhibit excellent activity due to the attachment of electron donating groups and were found modest in contrast with the standard marketed drug. Protein-ligand interactions were observed through in-silico docking studies and their drug likeness properties were studied through ADMET analysis.

Novel tryptamine decorated cyclotriphosphazene derived Schiff base compounds: Synthesis, characterization and molecular docking studies

In this study, new cyclotriphosphazene derivative Schiff base compounds including tryptamine units were synthesized for the first time. The structures of all compounds (2–9) were characterized by FT-IR, mass, 1H and 31P NMR spectra. In addition, the solid-state structure and geometry of salicylaldehyde-substituted cyclotriphosphazene compound 6 using as the precursor were determined by single-crystal X-ray analysis. Molecular docking studies were performed to elucidate the interactions between target molecules and the compounds under investigation, aiming to assess their therapeutic potential and predict their biological activities. Screening results revealed significant interactions between the compounds and key protein structures, including IGFBP, PI3K, LE, JAK3, and PTP-2, which are involved in critical cellular processes. Furthermore, in silico evaluations were conducted to analyze the physicochemical properties, pharmacokinetics, and toxicological profiles of synthesized compounds.

Synthesis, Characterization, Biological, ADMET, and Molecular Docking Studies of Transition Metal Complexes of Aminopyridine Schiff Base Derivative

Abstract1,2‐diphenylethane‐1,2‐diylidene)bis(azanylylidene))bis(pyridine‐3‐thiol) ligand was synthesized by refluxing 2‐aminopyridine‐3‐thiol with benzil in 2 : 1 molar ratio. Manganese(II), Cobalt(II), Nickel(II) and Copper(II) were also synthesized using the same method. All the compounds were characterized employing various analytical and spectroscopic methods, including melting point determination, molar conductance, magnetic moment measurement, 1H‐NMR, FTIR, mass spectrometry, EPR, and UV‐Visible spectroscopy. The antimicrobial potential of ligand and its complexes was assessed against B. subtilis, S. typhi, A. flavus, and M. phaseolina using the well‐diffusion method. Gentamycin and Amphotericin B were used as standard reference drugs. The complexes revealed more potent antimicrobial action than the ligand. Molecular docking studies were performed using crystal structures of B. subtilis, and A. flavus receptor proteins. In silico studies suggested the druglikeness potential of the synthesized compounds. The Nickel(II) complex showed superior biological efficacy based on the experimental and computational results.

Exploring the anti-diabetic activity of benzimidazole containing Schiff base derivatives: In vitro α-amylase, α-glucosidase inhibitions and in silico studies

The current study explores the anti-diabetic potential of some Schiff bases containing benzimidazole scaffold. These derivative were synthesized by refluxing sodium metabisulfite with ethyl 2-(2-ethoxy-6-formylphenoxy)acetate followed by the addition of ortho phenylene diamine in DMF solvent to get the benzimidazole which was further refluxed in hydrazine hydrate to obtain the hydrazide. Finally various substituted benzaldehydes were treated with the desired hydrazide using a catalytic quantity of acetic acid to obtain the hydrazone Schiff bases. These compounds were evaluated for their ability to inhibit α-amylase and α-glucosidase inhibitory potentials. Among them, six derivatives including 2g, 2h, 2q, 2p, 2i, and 2m displayed noteworthy inhibitory activities against α-amylase (IC50 = 2.15 ± 0.17 µM to 15.18 ± 3.29 µM ) and α-glucosidase (IC50 = 4.21 ± 0.78 to 16.10 ± 0.52 µM) superior than the standard acarbose, while the remaining compounds showed significant to less inhibitory activities. By clarifying the mechanisms of interaction between the chemicals and amino acid residues, the molecular docking analysis attempted to shed light on the binding modalities of these molecules. The reactivity indices of these compounds were calculated using the Density Functional Theory (TD-DFT) approach, employing the B3LYP-d energy function and lacvp**(d,p) basis set for calculations. Schiff base derivatives based on benzimidazole, especially compounds 2h and 2g, exhibited lower electrophilicity and higher bioactivity compared to their counterparts 2i and 2m.