Benzaldehyde Moieties Research Articles

Synthesis, structural and antimicrobial studies of transition metal complexes of a novel Schiff base ligand incorporating 1,2,4-triazole and 4-(benzyloxy)benzaldehyde moieties

A Schiff base ligand named 4-(((5-mercapto-4H-1,2,4-triazole-4-yl)imino)methyl)-(benzyloxy)benzene (HL) and its bioactive series of Ni(II), Cu(II), Zn(II) and Cd(II) metal complexes having 1:1 and 2:1 ligand-to-metal ratio, have been synthesized. All the synthesized compounds were fully characterized by IR, 1H-NMR, elemental analysis, absorbance (UV-Vis.) and mass spectra. Furthermore, the molecular structure of the Schiff base was established by single-crystal X-ray diffraction analysis. Additionally, computational investigations of the compounds were conducted using the DFT/B3LYP method. This analysis involved the determination of FMO energy values, as well as the calculation of quantum chemical parameters. The binding effect of metal ions on the ligand's fluorescence intensity was probed using fluorescence spectroscopy. The thermal stability and kinetic parameters of the complexes were determined using TGA (Thermogravimetric Analysis) analysis via the Coats–Redfern method. The docking studies, actively explored the interaction between Schiff base ligand and protein receptor molecules of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. To assess the therapeutic potential, an in silico ADMET model was employed, revealing that the synthesized molecules exhibit drug-like properties. The Schiff base and all the derived metal complexes were screened for their antimicrobial potential against bacterial species like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and fungus Candida albicans.

Metal‐Free Substituent‐Controlled Direct Synthesis of Unprecedented Iminotetrazoles via One‐pot Ugi‐Azide Reaction

AbstractEasy operation, readily accessible starting materials, and direct synthesis of iminotetrazoles via metal‐free aerobic oxidation were achieved in one‐pot Ugi‐azide multicomponent reactions. A study of the reactivity of 2‐hydroxybenzaldehyde (Salicylaldehyde) as single reactant replacement (SSR) in classical Ugi reaction has been carried out showing an outcome that differs by simply varying the ortho‐substituents of the benzaldehyde moiety. In doing so, various substituted imino tetrazole products could be obtained directly in one step by simple execution without oxidation step in good yields. Characterization of these new iminotetrazole products was confirmed by X‐ray analysis.

Biologically Potent Benzimidazole-Based-Substituted Benzaldehyde Derivatives as Potent Inhibitors for Alzheimer's Disease along with Molecular Docking Study.

Twenty-one analogs were synthesized based on benzimidazole, incorporating a substituted benzaldehyde moiety (1-21). These were then screened for their acetylcholinesterase and butyrylcholinesterase inhibition profiles. All the derivatives except 13, 14, and 20 showed various inhibitory potentials, ranging from IC50 values of 0.050 ± 0.001 µM to 25.30 ± 0.40 µM against acetylcholinesterase, and 0.080 ± 0.001 µM to 25.80 ± 0.40 µM against butyrylcholinesterase, when compared with the standard drug donepezil (0.016 ± 0.12 µM and 0.30 ± 0.010 µM, against acetylcholinesterase and butyrylcholinesterase, respectively). Compound 3 in both cases was found to be the most potent compound due to the presence of chloro groups at the 3 and 4 positions of the phenyl ring. A structure-activity relationship study was performed for all the analogs except 13, 14, and 20, further, molecular dynamics simulations were performed for the top two compounds as well as the reference compound in a complex with acetylcholinesterase and butyrylcholinesterase. The molecular dynamics simulation analysis revealed that compound 3 formed the most stable complex with both acetylcholinesterase and butyrylcholinesterase, followed by compound 10. As compared to the standard inhibitor donepezil both compounds revealed greater stabilities and higher binding affinities for both acetylcholinesterase and butyrylcholinesterase.

A NIR Fluorescent Probe Benzopyrylium Perchlorate-based for Visual Sensing and Imaging of SO2 Derivatives in Living Cells.

Endogenous sulfur dioxide (SO2), as a gas signal molecule, has a certain physiological functions. Understanding the role of endogenous SO2 in human physiology and pathology is of great significance to the biological characteristics of SO2,which bringchallenges to develop fluorescent probes with excellent performance. Herein, we rationally designed and constructed a novel near-infrared bioprobe benzaldehyde-benzopyrylium (BBp) by employing the nucleophilic addition benzopyrylium perchlorate fluorophore and benzaldehyde moiety by means of C = C/C = O group that serves as both fluorescence reporting unit. Probe BBp exhibit excellent sensing performance with fluorescent "On - Off"rapid response (100s) and long-wavelength emission (670nm). With the treatment of HSO3-, the color of BBp solution obviously varies from purple to colorless, and the fluorescent color varies from red to colorless. By the fluorescence and colorimetric changes, probe BBp was capable of sensitive determination HSO3- with low limits of detection (LOD) of 0.43μM, realizing visual quantitative monitoring SO2 derivative levels. Due to the low phototoxicity and good biocompatibility, it was successfully applied to monitor SO2 derivatives and fluorescence imaging in HepG2 and HeLa living cells. Hopefully, this work supplies a new strategy for designing NIR fluorescent probes for quantitative determination SO2 derivatives in biological samples.

Two novel enzyme-free colorimetric sensors for the detection of glyphosate in real samples

The intensive use and accumulation of glyphosate cause many environmental and ecological problems. There is an urgent need for an effective detection method for glyphosate. Many studies in the literature determine glyphosate by an enzyme-based method, requiring appropriate temperature, pH, substrate and ionic strength. In this study, we presented a simple enzyme-free reaction system. Two new simple Schiff base derivatives, 4-(((3-chloropyridin-4-yl)imino)methyl)-N,N-dimethylaniline (BNP-Cl) and 4-((3-((3-chloropyridin-4-yl)imino)propenyl)-N,N-dimethylaniline (CNP-Cl), were prepared by combining a pyridine moiety with a cinnamaldehyde or a benzaldehyde moiety. The pyridine moiety contains a chlorine atom, and this chlorine atom is replaced by the nitrogen or oxygen of glyphosate (Glyp) in ACN/Tris buffer (pH=8.14, 10 mM, v/v 2:1). This binding caused color changes ranging from colorless to yellow for BNP-Cl and yellow to orange for CNP-Cl. The sensors BNP-Cl and CNP-Cl have a rapid and excellent selectivity for glyphosate with low detection limits (1.78 µM for BNP-Cl and 1.60 µM for CNP-Cl). The sensors were also successfully applied to detect Glyp in real samples such as soil, tap water, and potatoes.

Stress Relaxation and Composition of Hydrazone-Crosslinked Hybrid Biopolymer-Synthetic Hydrogels Determine Spreading and Secretory Properties of MSCs.

The extracellular matrix plays a critical role in mechanosensing and thereby influences the secretory properties of bone-marrow-derived mesenchymal stem/stromal cells (MSCs). As a result, interest has grown in the development of biomaterials with tunable properties for the expansion and delivery of MSCs that are used in cell-based therapies. Herein, stress-relaxing hydrogels are synthesized as hybrid networks containing both biopolymer and synthetic macromer components. Hyaluronic acid is functionalized with either aldehyde or hydrazide groups to form covalent adaptable hydrazone networks, which are stabilized by poly(ethylene glycol) functionalized with bicyclononyne and heterobifunctional small molecule crosslinkers containing azide and benzaldehyde moieties. Tuning the composition of these gels allows for controlled variation in the characteristic timescale for stress relaxation and the amount of stress relaxed. Over this compositional space, MSCs are observed to spread in formulations with higher degrees of adaptability, with aspect ratios of 1.60± 0.18, and YAP nuclear:cytoplasm ratios of 6.5± 1.3. Finally, a maximum MSC pericellular protein thickness of 1.45± 0.38µm occurred in highly stress-relaxing gels, compared to 1.05± 0.25µm in non-adaptable controls. Collectively, this study contributes a new understanding of the role of compositionally defined stress relaxation on MSCs mechanosensing and secretion.

Sustainable Claisen-Schmidt chalcone synthesis catalysed by plasma-recovered MgO nanosheets from seawater

Chalcones enable the biosynthesis of flavonoids which protect plants from infections and parasites and have emerged as valuable medicines against diverse human diseases. The common way to synthesize chalcones through the homogeneous catalytic Claisen-Schmidt condensation reaction is compromised from difficult catalyst recovery, waste generation, side reactions, and low yield. As a solution, solid base catalysts are developed as a green catalytic process. It is still a major challenge to synthesize highly active heterogeneous catalysts with a quick, simple, sustainable, and economical approach in the chalcone synthesis. To address these issues, a simple and sustainable synthesis of chalcones has been accomplished here by the solvent-free Claisen-Schmidt condensation reaction using magnesium oxide (MgO) nanosheets as the catalyst. The heterogeneous two-dimensional (2D) MgO catalyst was synthesized using salt recovered from inexhaustible seawater, using an atmospheric pressure plasma (APP)-assisted method making the whole method sustainable and potentially economically feasible. The catalytic activity of the 2D nanosheets was compared with irregular MgO nanoparticles. Irregular MgO showed 25% of benzaldehyde and 10% of acetophenone conversion, while 2D MgO showed >99% of conversion of both reactants with a product selectivity of 100%, while no products were formed in the absence of a catalyst. The effect of substituent groups on the benzaldehyde moiety on the catalytic activity was also analysed. The prepared 2D MgO catalyst showed reusability up to three cycles without any significant loss in the catalytic activity.

Modification of eggshell membrane to impart biospecific properties

AbstractEggshell membrane (ESM) represents an inexpensive, environmentally friendly and nontoxic byproduct. Besides the unique mechanical properties of the material, the ESM surface is rich in functional groups susceptible to further modifications. In the current study two modification pathways were applied to enrich the ESM surface with glucopyranosyl units. One was based on the reaction of activated surface carboxylic groups with glucosamine and the other exploited the reactivity of the surface amino groups for grafting poly(ethylene glycol) (PEG) chains bearing end glucopyranosyl and benzaldehyde moieties. The functionalization of the PEG chains with molar masses 400 and 1500 g mol−1 was evidenced from 1H NMR and 13C NMR spectral data. The modified ESMs were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The Brunauer–Emmett–Teller specific surface area and the total pore volume of ESM decreased upon modification. Decoration of ESM with glucopyranosyl units imparted protein recognition properties that were tested via binding studies with concanavalin A as model lectin. Further, grafting of glucose units via PEG linkers reduced bacterial adhesion onto the membrane surface. © 2021 Society of Industrial Chemistry.

Synthesis and antibacterial evaluation of pyrazolines carrying (benzyloxy)benzaldehyde moiety

Synthesis and antibacterial evaluation of pyrazolines carrying (benzyloxy)benzaldehyde moiety

Tracking Ultrafast Fluorescence Switch-On and Color-Tuned Dynamics in Acceptor-Donor-Acceptor Chromophore.

Understanding how the conformational change of conjugated molecules with acceptor-donor-acceptor (A-D-A) architecture affects their physical and optoelectronic properties is critical for determining their ultimate performance in organic electronic devices. Here, we utilized femtosecond transient absorption, time-resolved upconversion photoluminescence spectroscopy, and tunable femtosecond-stimulated Raman spectroscopy, aided by quantum chemical calculations, to systematically investigate the excited state structural dynamics of the intramolecular charge transfer of the tetramethoxy anthracene-based fluorophore 2,3,6,7-tetramethoxy 9,10-dibenzaldehydeanthracene (AnDA) and its derivative 2,3,6,7-tetramethoxy 9,10-diphenylanthracene (TMDPAn) in chloroform. In the AnDA molecule, the tetramethoxy anthracene and benzaldehyde moieties exhibit a strong ability to donate and withdraw electrons. Upon photoexcitation, AnDA shows intriguing ultrafast fluorescence switch-on and red shift dynamics on charge transfer states, and the temporal evolution of AnDA recorded by ultrafast spectroscopy reveals a dynamic picture of two-step intramolecular charge transfer assisted by ultrafast conformational changes and solvation processes. Removing the aldehyde group from TMDPAn significantly decreases the electron pulling capacity of the phenyl unit and disables charge transfer characteristics.

Light‐Gated Control of Conformational Changes in Polymer Brushes

AbstractHerein, a strategy to control conformational changes in grafted polymer brushes via photoinduced crosslinking of photoreactive groups embedded into the lateral architecture of a polymer brush is reported. Poly(methylmethacrylate)‐based polymer brushes containing UV‐light (λ = 325 nm) photoreactive o‐methyl benzaldehyde moieties are synthesized using surface‐initiated reversible deactivation polymerization. The conformational changes in polymer brushes upon UV‐light triggered crosslinking are comprehensively analyzed through a full suite of surface sensitive characterization methods including time of flight secondary ion mass spectrometry, quartz crystal microbalance with dissipation monitoring, UV/vis spectroscopy, atomic force microscopy, nanoplasmonic sensing, and neutron reflectometry. The spatiotemporal control of the induced conformational changes is demonstrated via photolithography experiments. To enable an additional level of control, a second gate, the visible light (λ = 445 nm) active styrylpyrene moiety, is incorporated into the polymer brush architecture. Critically, wavelength‐selective crosslinking behavior is observed in the diblock copolymer structures allowing to crosslink specific sections of the lateral brush architecture as a function of irradiation wavelength.

Two Novel Fluorescent Probes as Systematic Sensors for Multiple Metal Ions: Focus on Detection of Hg2.

Many precedents prove that fluorescent probes are promising candidates for detection of metal ions in the environment and biological systems. Herein, two novel photoinduced electron transfer (PET)-based fluorescent probes, CH3-R6G and CN-R6G, were rationally synthesized by incorporating a triazolyl benzaldehyde moiety into the rhodamine 6G fluorophore. The optical properties of these probes were studied using an ultraviolet–visible (UV–vis) absorption spectrophotometer and a fluorescence spectrophotometer. Through the analysis of the test results, it is concluded that the selectivity and sensitivity of these two probes to Hg2+ are better than to other metal ions (Ag+, Al3+, Ba2+, Cd2+, Co3+, Cu2+, Cr3+, Fe3+, Ga2+, K+, Mg2+, Na+, Ni2+, Pb2+, and Zn2+). According to the standard curve diagram, the detection limits of CH3-R6G and CN-R6G were determined to be 1.34 × 10–8 and 1.56 × 10–8 M, respectively. Reaction of the probes with Hg2+ resulted in a color change of the solution from colorless to pink. The corresponding molecular geometric configuration, orbital electron distribution, and orbital energy of these two compounds were predicted by density functional theory (DFT). The two probes CH3-R6G and CN-R6G have been successfully used for imaging Hg2+ in live breast cancer cells, thereby indicating their great potential for the micro-detection of Hg2+ in vivo.

Hydrogenation of plant polyalkoxybenzene derivatives: convenient access to coenzyme Q0 analogues

A technologically advanced protocol has been developed for converting plant allyl(polyalkoxy)benzenes to methyl- and propyl(polyalkoxy)benzenes being intermediates in the syntheses of coenzyme Q0 analogues. The key stage of allyl and benzaldehyde moieties hydrogenation was carried out in a periodical autoclave mode on highly porous ceramic block Pd-catalysts. These catalysts possess large surface area, low hydraulic resistance, significant thermal and mechanical stabililty, multiple cycling and easy regeneration, which can dramatically reduce Pd consumption.

Multifunctional isoxazolidine derivatives as α-amylase and α-glucosidase inhibitors.

A series of novel isoxazolidines based on benzaldehyde derivatives have been synthesized from the cycloaddition of chiral menthone-based nitrone and allyl phenyl ethers. All synthetic compounds were assessed for their in vitro PPA, HPA and HLAG inhibitory activity. The results revealed that all targets exhibited better inhibitory effect against PPA (12.3±0.4<IC50<38.2±0.9μM), HPA (10.1±0.4<IC50<26.8±0.2μM) and HLAG (65.4±1.2<IC50<274.8±1.1μM) when compared with the reference inhibitor, acarbose (IC50=284.6±0.3μM for PPA, 296.6±0.8μM for HPA, 780.4±0.3μM for HLAG) with the highest PPA inhibitory activity was ascribed to compound 3g against both PPA and HPA, and 3b against HLAG enzymes, respectively. Structural activity relationships (SARs) were also established for all synthesized compounds and the interaction modes of the most potent inhibitors (3g for PPA and HPA, 3b for HLAG) and the active site with residues of three enzymes were confirmed through molecular docking studies. Furthermore, a combination of molecular docking analysis with the in vitro activities can help to improve prediction success and encourages the uses of some of these molecules as potential alternatives toward the modulation of T2D.

Designing, preparation and evaluation of the antimicrobial activity of biomaterials based on chitosan modified with silver nanoparticles

Chitosan was chemically modified through a four-step procedure. First, the amino groups of chitosan have reacted with benzaldehyde (Derivative 1); second, hydroxyl groups on C6 of Derivative 1 have reacted with epichlorohydrin (Derivative 2); third, the epoxy groups of Derivative 2 have reacted with 4-aminosalicylic acid (Derivative 3); and fourth, benzaldehyde moieties of Derivative 3 have been removed to retrieve the amino groups (Derivative 4). For further modification, three nano-biocomposites were synthesized via impregnating three different concentrations of silver nanoparticles inside Derivative 4. These derivatives and Derivative 4/AgNP composites were structurally identified using elemental analysis, FTIR, XPS, 1H NMR, XRD, SEM, EDS and TEM techniques. These derivatives and Derivative 4/AgNP composites have superior antimicrobial activities than virgin chitosan. Some of them have inhibition zone analogous or superior than the utilized reference drugs. Cytotoxic activity of Derivative 4 and Derivative 4/AgNPs-5 composite indicated that these materials are safe on normal human cells. Accordingly, combinations between chitosan and functional groups derived from the different modifiers in addition to AgNPs within a single structure have extraordinarily enhanced the efficiency of chitosan. It might be deemed as a path to attain promising frameworks which are taken as proper competitors for antimicrobial materials in biomedical fields.

Intramolecular Benzoin Reaction Catalyzed by Benzaldehyde Lyase from Pseudomonas Fluorescens Biovar I.

Intramolecular benzoin reactions catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I (BAL) are reported. The structure of the substrates envisaged for this reaction consists of two benzaldehyde derivatives linked by an alkyl chain. The structural requirements needed to achieve the intramolecular carbon-carbon bond reaction catalyzed by BAL were established. Thus, a linker consisting of a linear alkyl chain of three carbon atoms connected through ether-type bonds to the 2 and 2' positions of two benzaldehyde moieties, which could be substituted with either Cl, Br, or OCH3 at either the 3 and 3' or 5 and 5' positions, were suitable substrates for BAL. Reactions with 61-84 % yields of the intramolecular product and ee values between 64 and 98 %, were achieved.

Discovery and biological evaluation of some (1H-1,2,3-triazol-4-yl)methoxybenzaldehyde derivatives containing an anthraquinone moiety as potent xanthine oxidase inhibitors

A series of (1H-1,2,3-triazol-4-yl)methoxybenzaldehyde derivatives containing an anthraquinone moiety were synthesized and identified as novel xanthine oxidase inhibitors. Among them, the most promising compounds 1h and 1k were obtained with IC50 values of 0.6μM and 0.8μM, respectively, which were more than 10-fold potent compared with allopurinol. The Lineweaver-Burk plot revealed that compound 1h acted as a mixed-type xanthine oxidase inhibitor. SAR analysis showed that the benzaldehyde moiety played a more important role than the anthraquinone moiety for inhibition potency. The basis of significant inhibition of xanthine oxidase by 1h was rationalized by molecular modeling studies.

PH-Responsive Tumor-Targetable Theranostic Nanovectors Based on Core Crosslinked (CCL) Micelles with Fluorescence and Magnetic Resonance (MR) Dual Imaging Modalities and Drug Delivery Performance.

The development of novel theranostic nanovectors is of particular interest in treating formidable diseases (e.g., cancers). Herein, we report a new tumor-targetable theranostic agent based on core crosslinked (CCL) micelles, possessing tumor targetable moieties and fluorescence and magnetic resonance (MR) dual imaging modalities. An azide-terminated diblock copolymer, N3-POEGMA-b-P(DPA-co-GMA), was synthesized via consecutive atom transfer radical polymerization (ATRP), where OEGMA, DPA, and GMA are oligo(ethylene glycol)methyl ether methacrylate, 2-(diisopropylamino)ethyl methacrylate, and glycidyl methacrylate, respectively. The resulting diblock copolymer was further functionalized with DOTA(Gd) (DOTA is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakisacetic acid) or benzaldehyde moieties via copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) chemistry, resulting in the formation of DOTA(Gd)-POEGMA-b-P(DPA-co-GMA) and benzaldehyde-POEGMA-b-P(DPA-co-GMA) copolymers. The resultant block copolymers co-assembled into mixed micelles at neutral pH in the presence of tetrakis[4-(2-mercaptoethoxy)phenyl]ethylene (TPE-4SH), which underwent spontaneous crosslinking reactions with GMA residues embedded within the micellar cores, simultaneously switching on TPE fluorescence due to the restriction of intramolecular rotation. Moreover, camptothecin (CPT) was encapsulated into the crosslinked cores at neutral pH, and tumor-targeting pH low insertion peptide (pHLIP, sequence: AEQNPIYWARYADWLFTTPLLLLDLALLVDADEGTCG) moieties were attached to the coronas through the Schiff base chemistry, yielding a theranostic nanovector with fluorescence and MR dual imaging modalities and tumor-targeting capability. The nanovectors can be efficiently taken up by A549 cells, as monitored by TPE fluorescence. After internalization, intracellular acidic pH triggered the release of loaded CPT, killing cancer cells in a selective manner. On the other hand, the nanovectors labeled with DOTA(Gd) contrast agents exhibited increased relaxivity (r1 = 16.97 mM−1·s−1) compared to alkynyl-DOTA(Gd) small molecule precursor (r1 = 3.16 mM−1·s−1). Moreover, in vivo MRI (magnetic resonance imaging) measurements revealed CCL micelles with pHLIP peptides exhibiting better tumor accumulation and MR imaging performance as well.

Novel phthalocyanine–BODIPY conjugates and their photophysical and photochemical properties

Novel zinc(II) phthalocyanines bearing boron dipyrromethene (BODIPY) (8) and its mono-styryl (9) and di-styryl (10) derivatives containing p-(N,N-diethylamino)benzaldehyde moieties were designed and synthesized for the first time. These phthalocyanines (8–10) were prepared by the copper-free Sonogashira coupling reaction of terminal ethynyl functionalized BODIPYs [4,4′-difluoro-8-(4-propynyloxy)-phenyl-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (2), 4,4′-difluoro-8-(4-propynyloxy)-phenyl-3,5,7-trimethyl-1-((4-diethylaminophenyl)ethenyl)-4-bora-3a,4a-diaza-s-indacene (5), or 4,4′-difluoro-8-(4-propynyloxy)-phenyl-3,5-dimethyl-1,7-bis((4-4″-diethylaminophenyl)ethenyl)-4-bora-3a,4a-diaza-s-indacene (6)] with tetrakis(iodo) zinc(II) phthalocyanine (7). All newly synthesized compounds were fully characterized by elemental analysis and general spectroscopic methods such as 1H NMR, FT-IR, mass, UV–Vis, and fluorescence. The photophysical (fluorescence quantum yields and lifetimes), photochemical (singlet oxygen generation capability and photodegradation behaviors) properties of these phthalocyanines were also investigated for determination of their photodynamic therapy (PDT). The results obtained indicated that these conjugates could be promising photosensitizers for PDT applications.

Nonlinear optical properties of intriguing Ru σ-acetylide complexes and the use of a photocrosslinked polymer as a springboard to obtain SHG active thin films.

This work reports on the design, synthesis and photo-physical properties of two ruthenium σ-alkynyl complexes. It is shown that, despite similar optical absorption features recorded in solution, the introduction of a benzaldehyde moiety leads to an improved non-linear optical (NLO) response as measured by Electric Field Induced Second Harmonic (EFISH) generation and Third Harmonic Generation (THG) at 1.907 μm, both related to the second order hyperpolarizability. These structure-property relationships are rationalized based on few state modelling. Complex is subsequently processed to afford composite films that demonstrate a χ(2) of 1.4 pm V(-1), quite remarkable given the ease of film processing implemented in this work.