Schiff Base Formation Research Articles

Coumarin Schiff Base Derivatives with 4’-Alkoxy Biphenyl-4-carboxaldehyde: Synthesis, Mesomorphic studies and DFT Calculations

Two homologous series of coumarin Schiff base derivatives with 4’-alkoxy biphenyl-4-carboxaldehyde have been designed and synthesized. All the compounds were analyzed IR, 1H-NMR, 13C-NMR, ESI-MS and CHN analysis followed by mesomorphic properties polarizing optical microscopy (POM) and differential scanning calorimetry (DSC) analysis. In the first homologous series BPS(6-16), Schiff base of 7-alkoxy-3-aminocoumarin with 4’-alkoxy biphenyl-4-carboxaldehyde, alkoxy chain length was varied systematically at both end of the molecules such as n=6,8,10,12,14,16. In this series, BPS(6-10) (n=6,8,10) exhibited enantiotropic nematic(N) and smectic C (SmC) mesophase and turned to monophasic on increasing the chain length n=12,14,16 in BPS(12-16) with stable SmC mesophase. While in the second homologous series 10BPU(2-16), systemic variation of alkoxy chain length was carried out at coumarin end only (n=2-18) and 4’-decyloxy-biphenyl-4-carboxaldehyde was used for Schiff base formation. In the this series, early member of the series with n=2,3 showed enantiotropic very stable (∼ 145 °C) nematic mesophase, while N as well as SmC mesophase were observed for n=4-8 at, whereas with increase of chain length stability of nematic mesophase was decreased and that of SmC was increased. Higher membered analogous 10BPU(12-16) exhibited SmC mesophase with stability in the rage of 130-160 °C. VT-XRD analysis was also confirmed the tilted SmC mesophase in this class of compounds. For both the series, all compounds were studied for the DFT calculations as well as literature molecules with similar variations. Based on the calculated structural (length, aspect ratio) and electronic (dipole moment, polarizability) parameters were correlated with mesomorphic behaviour observed for literature compounds and compounds from both the series followed by the detailed discussion.

Three-metal ion mechanism of cross-linked and uncross-linked DNA polymerase β: A theoretical study.

In our recent publication, we have proposed a revised base excision repair pathway in which DNA polymerase β (Polβ) catalyzes Schiff base formation prior to the gap-filling DNA synthesis followed by β-elimination. In addition, the polymerase activity of Polβ employs the "three-metal ion mechanism" instead of the long-standing "two-metal ion mechanism" to catalyze phosphodiester bond formation based on the fact derived from time-resolved x-ray crystallography that a third Mg2+ was captured in the polymerase active site after the chemical reaction was initiated. In this study, we develop the models of the uncross-linked and cross-linked Polβ complexes and investigate the "three-metal ion mechanism" vs the "two-metal ion mechanism" by using the quantum mechanics/molecular mechanics molecular dynamics simulations. Our results suggest that the presence of the third Mg2+ ion stabilizes the reaction-state structures, strengthens correct nucleotide binding, and accelerates phosphodiester bond formation. The improved understanding of Polβ's catalytic mechanism provides valuable insights into DNA replication and damage repair.

Multifunctional Self-Healing Carbon Dot-Gelatin Bioadhesive: Improved Tissue Adhesion with Simultaneous Drug Delivery, Optical Tracking, and Photoactivated Sterilization.

Bioadhesives with all-inclusive properties for simultaneous strong and robust adhesion, cohesion, tracking, drug delivery, self-sterilization, and nontoxicity are still farfetched. Herein, a carbon dot (CD) is made to infuse each of the above-desired aspects with gelatin, an inexpensive edible protein. The CD derived through controlled hydrothermal pyrolysis of dopamine and terephthaldehyde retained -NH2, -OH, -COOH, and, most importantly, -CHO functionality on the CD surface for efficient skin adhesion and cross-linking. Facile fabrication of CD-gelatin bioadhesive through covalent conjugation of -CHO of the CD with -NH2 of gelatin through Schiff base formation was accomplished. This imparts remarkable self-healing attributes as well as excellent adhesion and cohesion evident from physicomechanical analysis in a porcine skin model. Improved porosity of the bioadhesive allows loading hemin as a model drug whose disembarkment is tracked with intrinsic CD photoluminescence. In a significant achievement, antibiotic-free self-sterilization of bioadhesive is demonstrated through visible light (white LED, 23 W)-irradiated photosensitization of the CD to produce reactive oxygen species for annihilation of both Gram-positive and Gram-negative bacteria with exceptional efficacy (99.9%). Thus, a comprehensive CD-gelatin bioadhesive for superficial and localized wound management is reported as a promising step for the transformation of the bioadhesive domain through controlled nanotization for futuristic clinical translations.

Synthesis of new quaternized chitosan Schiff bases and their N-alkyl derivatives as antimicrobial and anti-biofilm retardants in membrane technology

New quaternized salicylidene chitosan Schiff bases (QSCSBs) and their N-octyl derivatives (OQCs) have been synthesized and characterized, aiming to develop innovative antimicrobial and anti-biofilm agents. This research holds immense potential, as these compounds could be utilized as anti-biofouling additives in membrane technology in the future. The synthesis involved the modification of low molecular-weight-chitosan (LMC) through simultaneous Schiff base formation and quaternization processes to create QSCSBs. Subsequently, QSCSBs were catalytically reduced to form quaternized N-benzyl chitosan (QBCs) intermediates, which then underwent nucleophilic substitution reactions affording N-octyl quaternized chitosans (OQCs). Characterization techniques such as elemental, spectral, and microscopic analyses were used to confirm the successful synthesis of these materials. As membrane technology relies on surface charge, QSCSBs and OQCs with large zeta potentials could be used as positively charged additives. Moreover, SEM image revealed the regular distribution of pores and voids across the additives' surfaces raises intriguing questions about their implications for membrane performance. Meanwhile, the superior antibacterial and antibiofilm potential of these materials, particularly QSCSB2 and OQC2, indicate that the utilization of these compounds as anti-biofouling additives in membrane technology could significantly improve the performance and longevity of membranes used in various applications such as water treatment and desalination.

Voltametric Sensor Based on Magnetic Chitosan Acetylindole-Based Nanocomposite for the Determination of Sulfamethazine.

Sulfamethazine (SMZ), a persistent antibiotic, is frequently detected in drinking water and milk. For this reason, our research aimed to develop a novel electrochemical sensor based on a magnetic nanocomposite supported on chitosan modified by 3-acetylindole through the formation of chitosan acetylindole Schiff base (Chs-Aci). The objective was to detect extremely low concentrations of SMZ in milk. The synthesized nanocomposites were characterized by various techniques, including FT-IR, XRD, EDX, SEM, and TEM. To enhance the electrocatalytic efficiency for sensitive SMZ detection in food samples, a magnetic chitosan acetylindole nanocomposite (M-Chs-Aci) was employed as a modifier for a carbon paste electrode (CPE). The electrochemical measurements revealed that the M-Chs-Aci/CPE exhibits good electrocatalytic performance compared to a bare CPE. Moreover, low detection limit, repeatability, and stability were achieved at 0.021 μM, 3.83%, and 94.87%, respectively. Finally, the proposed M-Chs-Aci/CPE proved to be highly effective in detecting SMZ in milk samples. The obtained findings paved the way for the effective usability of M-Chs-Aci/CPE as a sensor for detecting SMZ in real samples, with acceptable recoveries of 95%-98.87%.

Synthesis of multi-stimuli-responsive solid-state red-emitting phenothiazine-based A-π-D-π-A' derivatives and their applications

We report the synthesis of four A-π-D-π-A' type red-emitting multi-stimuli-responsive organic compounds exhibiting large Stokes shifts and displaying efficient emission in the solid-state (Φf = 19.6–66.7%). Fine tuning in the photophysical properties was achieved by structural modification, which converted a non-emissive compound to an emissive one. The compounds were sensitive to solvent polarity, displayed reversible acidofluorochromism, and could detect trifluoroacetic acid (TFA) in nanomolar range (51.43-274.84 nM). One of the probes not only displayed turn-on emission enhancement upon addition of H+ ions but was also sensitive to primary amines. A detailed mechanism for reversible acidofluorochromism was studied by 1H NMR, whereas formation of Schiff bases upon treatment with primary amine was confirmed by 1H NMR and HRMS. In addition to this, compounds also displayed reversible acidofluochromism in solid-state and the paper strips for the detection of TFA were prepared to increase their practical applicability. Further, solid-state emission property was utilized for anti-counterfeiting writing applications.

Synthesis and real-time characterization of self-healing, injectable, fast-gelling hydrogels based on alginate multi-reducing end polysaccharides (MREPs)

Polysaccharide-based hydrogels are promising for many biomedical applications including drug delivery, wound healing, and tissue engineering. We illustrate herein self-healing, injectable, fast-gelling hydrogels prepared from multi-reducing end polysaccharides, recently introduced by the Edgar group. Simple condensation of reducing ends from multi-reducing end alginate (M-Alg) with amines from polyethylene imine (PEI) in water affords a dynamic, hydrophilic polysaccharide network. Trace amounts of acetic acid can accelerate the gelation time from hours to seconds. The fast-gelation behavior is driven by rapid Schiff base formation and strong ionic interactions induced by acetic acid. A cantilever rheometer enables real-time monitoring of changes in viscoelastic properties during hydrogel formation. The reversible nature of these crosslinks (imine bonds, ionic interactions) provides a hydrogel with low toxicity in cell studies as well as self-healing and injectable properties. Therefore, the self-healing, injectable, and fast-gelling M-Alg/PEI hydrogel holds substantial promise for biomedical, agricultural, controlled release, and other applications.

Polysaccharide Aldehydes and Ketones: Synthesis and Reactivity.

Polysaccharides are biodegradable, abundant, sustainable, and often benign natural polymers. The achievement of selective modification of polysaccharides is important for targeting specific properties and structures and will benefit future development of highly functional, sustainable materials. The synthesis of polysaccharides containing aldehyde or ketone moieties is a promising tool for achieving this goal because of the rich chemistry of aldehyde or ketone groups, including Schiff base formation, nucleophilic addition, and reductive amination. The obtained polysaccharide aldehydes or ketones themselves have rich potential for making useful materials, such as self-healing hydrogels, polysaccharide-protein therapeutic conjugates, or drug delivery vehicles. Herein, we review recent advances in synthesizing polysaccharides containing aldehyde or ketone moieties and briefly introduce their reactivity and corresponding applications.

Two dysprosium single molecule magnets with planar skeleton built from edge-shared Dy3 triangles

Two dysprosium clusters [Dy4(µ3-OH)2(L1)6(L2)2]·2CH3CN (1) and [Dy6(µ3-OH)2(L3)2(HL3)2(H2L3)2(EtOH)2Cl2]Cl2·2EtOH·4CH3CN (2) bearing in-situ formed Schiff base ligands (H2L2 and H3L3) were obtained from the solvothermal reactions of Dy(NO3)3∙5H2O with 8-hydroxyquinoline-2-carboxaldehyde and anthranilic acid (HL1), and DyCl3∙6H2O with 5-bromo-2-hydroxybenzaldehyde and 2-methyl-2-amino-1,3-propanediol, respectively. They present planar tetranuclear and hexanuclear skeletons constructed from two and four edge-shared triangular Dy3 units for 1 and 2, respectively. Magnetic tests showed that both titled dysprosium clusters are field-induced single molecule magnets. Ab initio calculations were also performed to interpret their SMM performances. Single molecule magnets bearing such planar skeletons are rarely reported.

Lignin based water-soluble fluorescent macromolecular probes for the detection of Fe3+ ion

Lignin is an abundant biomass material in the natural world, its application value and application scope ought to be enlarged. In this work, dealkalized lignin with good water-solubility was used to combine with water-insoluble boron-dipyrromethene (BODIPY) fluorophore to obtain readily water-soluble macromolecular probes. Firstly, a small molecular fluorescent BODIPY probe with two amino groups (-NH2) and another small molecular fluorescent probe with two chlorine groups (-Cl) were synthesized. Secondly, the small-molecular fluorescent probe with two -NH2 groups reacted with carbonyl groups in the lignin by Schiff base formation reaction. Meanwhile, the small-molecular fluorescent probe with two -Cl groups reacted with hydroxyl groups in the lignin by Williamson ether formation reaction. Eventually, two lignin-based fluorescent probes were obtained. The molecular weights of the two probes reached 22.4kDa and 20.1kDa. Moreover, these two fluorescent probes were readily soluble in H2O and DMF. Both of the fluorescent macromolecules have good recognition ability for Fe3+, with detection limits of 2.1×10-7mol/L and 1.1×10-7mol/L respectively. Fe3+ interacts with the fluorescent probe, and the imine bond (-C=N-) reacts with Fe3+ to cause fluorescence response. The photo-induced electron transfer effect is enhanced, and the photo-induced electron transfer (PET) mechanism causes the fluorescent quenching. This work expands the application scope of lignin as a biomass material and lays a foundation for the development of lignin materials.

Study of Injectable Hydrogel Based on ALN/nHA Promoting Osteogenesis and Inhibiting Osteoclasts in Osteoporotic Bone Defects Repair.

Osteoporotic bone defects cannot withstand surgery with more significant trauma due to bone fragility, while systemic drug therapy has formidable adverse effects. Consequently, the present study introduces an innovatively devised injectable double-crosslinked hydrogel, as a potential therapeutic avenue for addressing varied shapes of osteoporotic bone defects via a minimally invasive approach. The injectable hydrogel is formed by the formation of Schiff base bonds between oxidized sodium alginate (OSA) and carboxymethyl chitosan, and the polymerization of gelatin methacrylate by UV light crosslinking. Additionally, alendronate sodium (ALN) is loaded into the hydrogel through Schiff base formation with OSA, and nanohydroxyapatite (nHA) is incorporated into the hydrogel via blending. The hydrogel demonstrates excellent injectability, and the nHA improves the mechanical properties of hydrogel and can promote bone formation. In addition, the hydrogel can sustain the release of ALN, which has the effect of inhibiting osteoclasts. Cell studies indicate that the hydrogel can promote the differentiation of osteoblasts and inhibit the activity of osteoclast, so as to obtain better osteogenic effect. Therefore, the injectable hydrogel can be used to repair osteoporotic bone defects through a minimally invasive, simple treatment modality.

Mass Spectrometry Evidence for Forming Schiff Base 3'-DNA-Histone Cross-Links from Abasic Sites in Vitro and in Human Cells.

Histones catalyze DNA strand incision at apurinic/apyrimidinic (AP) sites accompanied by the formation of reversible but long-lived DNA-protein cross-links at 3'-termini (3'-histone-DPCs). However, the chemical structures of 3'-histone-DPCs are not well characterized, and whether they are formed in cells is uncertain. In this study, we developed a liquid chromatography with tandem mass spectrometry workflow to characterize DPCs produced from the reaction of histones with AP sites and wish to report evidence that histones cross-link to incised AP sites via Schiff bases. We also demonstrated for the first time that 3'-histone-DPCs are produced endogenously in human embryonic kidney 293T cells.

Chitosan polymers randomly labeled with pyrene: synthesis, photophysics, and selective quenching by metal cations and anions

The synthesis together with a comprehensive electronic spectral and photophysical study of two chitosan polymers randomly labeled with different degrees of pyrene were here undertaken. The polymers, denoted as ChiNPy-A and ChiNPy-B, have different degrees of substitution with pyrene (%DSPy), with values of 0.5 and 4.5, respectively. The resulting polymers consist in four distinct units, including the deacetylated and acetylated units and the grafted imine and amine pyrene units, obtained by a Schiff base formation reaction and subsequent reduction, respectively. Time-resolved fluorescence measurements in aqueous solution revealed triple exponential decay fits that characterizes the fluorescence properties of the amine- and imine-pyrene-linked units, as well as self-quenching of pyrene units. The ChiNPy polymer showed fluorescence quenching of its pyrene amine units, with lead (II) and mercury (II) exhibiting the highest degree of fluorescence quenching. From Stern-Volmer type plots, two distinct populations of fluorophores were observed. These findings emphasize the potential of chitosan pyrene-labeled polymers as sensitive fluorescent probes, particularly for detecting metal cations.

Improving the barrier properties of chitosan coatings through Schiff base formation and halloysite incorporation for corrosion protection of commercially pure aluminum (cp-Al).

Coatings of chitosan modified with vanillin and containing halloysite nanotubes as filler were produced for corrosion protection of commercially pure aluminum (cp-Al). Modifications were characterized by Fourier-transform infrared spectroscopy (FTIR) and the degree of modification was determined by the ninhydrin assay, using UV–vis spectroscopy. Chitosan-modified coatings had their anticorrosive performance evaluated in 3.5 wt% NaCl solution through linear polarization and electrochemical impedance spectroscopy (EIS). Results showed an increase in the anticorrosive efficiency of the films with the increase of the degree of modification, which was related to the decrease of the electrolyte permeation through the coatings. The effect of the filler’s addition was evaluated by EIS analysis, SEM images coupled with EDS and analysis of the degree of swelling in 3.5 wt% NaCl. The electrochemical assays demonstrated that the addition of halloysite in low concentrations (up to 1%) improves the barrier properties of the films leading to a higher anticorrosive efficiency. It was also observed that with 10% halloysite occurs a phase separation responsible for the expressive increase in the degree of swelling of the samples and loss of barrier properties.

Stereoselective synthesis and antiproliferative activity of allo-gibberic acid-based 1,3-aminoalcohol regioisomers.

A new library of allo-gibberic acid-based aminoalcohol regioisomers was synthesised stereoselectively starting from commercially available gibberellic acid, which yields allo-gibberic acid under mild acidic conditions. The successful formation of hydroxymethyl ketone derivative 5, by acid-mediated rearrangement of previously prepared epoxide, paved the way to obtain the desired 1,3-aminoalcohols through Schiff base formation. To obtain the desired regioisomers, the primary alcohol functionality of 5 was subjected to mesylation, then replaced with either primary amine or sodium azide. The formed azide derivative was subjected to either CuAAC reaction to obtain 1,2,3-triazoles or underwent Pd-catalysed hydrogenolysis to obtain primary aminoalcohol, which was further transformed into 1,3-aminoalcohols by reductive alkylation. All prepared aminoalcohols were identified in a satisfactory manner using modern spectroscopic techniques and assessed for their antiproliferative activity against a panel of human cancer cell lines. The antiproliferative effects of the prepared compounds were assayed by in vitro MTT method against a panel of human cancer cell lines (HeLa, SiHa, A2780, MCF-7 and MDA-MB-231). A significant difference was observed in the antiproliferative activity between the regioisomers. Some compounds exerted outstanding activities against the malignant cells with limited action on fibroblasts, indicating considerable cancer selectivity.

Synthesis and biological activity of imidazole phenazine derivatives as potential inhibitors for NS2B-NS3 dengue protease

A series of new imidazole-phenazine derivatives were synthesized via a two-step process. The condensation of 2,3-diaminophenazine and benzaldehyde derivatives proceeds with intermediate formation of an aniline Schiff base, which undergoes subsequent cyclodehydrogenation in situ. The structures of the synthesized compounds were characterized by 1D and 2D NMR, FTIR and HRMS. A total of thirteen imidazole phenazine derivatives were synthesized and validated for their inhibitory activity as anti-dengue agents by an in vitro DENV2 NS2B-NS3 protease assay using a fluorogenic Boc-Gly-Arg-Arg-AMC substrate. Two para-substituted imidazole phenazines, 3e and 3k, were found to be promising lead molecules for novel NS2B-NS3 protease inhibitors with IC50 of 54.8 μM and 71.9 μM, respectively, compared to quercetin as a control (IC50 104.8 μM). The in silico study was performed using AutoDock Vina to identify the binding energy and conformation of 3e and 3k with the active site of the DENV2 NS2B-NS3 protease Wichapong model. The results indicate better binding properties of 3e and 3k with calculated binding energies of −8.5 and −8.4 kcal mol−1, respectively, compared to the binding energy of quercetin of −7.2 kcal mol−1, which corroborates well with the experimental observations.

Rapid Analysis of Trace Amounts of Amino Acid Derivatives by a Formyl Group-Installed Crystalline Sponge.

The Industries need techniques for the rapid structure analysis of amino acid derivatives. The amino acid derivatives are sometimes produced as impurities in the industrial production processes, and cause toxicity problems. Herein, we report the crystalline sponge (CS) method analysis of variety of amino acids using a formyl group installed CS crystal. Most amino acids possess a primary amino group, which can form Schiff-base with the formyl group under mild conditions. Thus, the formyl group installed CS crystal can efficiently capture the amino acids via Schiff-base formation. We successfully analyzed derivatives of 18 proteogenic amino acids, 6 non-proteogenic amino acids, and 4 dipeptides using the formyl group installed CS. We thus believe that the protocols shown in this study would serve the need of the industries.

Synthesis of a Multifunctional Glyco-Block Copolymer through Reversible Addition-Fragmentation Chain Transfer Polymerization and Click Chemistry for Enzyme and Drug Loading into MDA-MB-231 Cells.

Reversible addition-fragmentation chain transfer polymerization has been used in various applications such as preparing nanoparticles, stimulus-responsive polymers, and hydrogels. In this study, the combination of this polymerization method and Cu(I)-catalyzed azide-alkyne cycloaddition click chemistry was used to prepare the multifunctional glyco-diblock copolymer P(PEG-co-AM)-b-PF, which is composed of mannosides for cell targeting, poly(ethylene glycol) (PEG) for biocompatibility, and aryl-aldehyde moieties for enzyme immobilization. The alkyne group in the polymer structure enables the alternation for other azide-conjugated monomers. The stepwise synthesis of the polymers was fully characterized. P(PEG-co-AM)-b-PF was self-assembled into polymeric nanoparticles (BDOX-GOx@NPs) for glucose oxidase immobilization through Schiff base formation and for encapsulating the prodrug of arylboronate-linked doxorubicin (BA-DOX) under optimal conditions. Glucose oxidase in BDOX-GOx@NPs catalyzes glucose oxidation to produce gluconic acid and H2O2, which cause oxidative stress. Glucose oxidase also consumes glucose, causing starvation in cancer cells. The produced H2O2 can selectively activate the anticancer prodrug BA-DOX for chemotherapy. In vitro data indicate that GOx and the prodrug BA-DOX present inside BDOX-GOx@NPs exhibit higher stability than free glucose oxidase with a favorable active DOX release profile. MDA-MB-231 cells, which express mannose receptors, were used to establish a model in this study. The bioactivity of the nanoplatform in the two- and three-dimensional models of MDA-MB-231 cancer cells was investigated to ascertain its antitumor efficacy.

Molecular structure, characterization, in vitro and in-silico studies of N,N-dimethyl aminophenyl schiff's base-chalcone hybrid

This study reports the synthesis and characterization of a novel compound, a chalcone-based Schiff base (SBC), with potential applications in anti-inflammatory and anti-diabetic treatments. Chalcones, known for their diverse biological activities, are combined with Schiff bases, versatile compounds, to create the SBC. The synthesis process involves aldol condensation and Schiff base formation. The compound's structure is confirmed through NMR, FT-IR, and mass spectroscopic analyses. The UV-visible spectroscopy reveals the compound's electronic properties, and molecular docking experiments indicate its potential to interact with enzymes related to inflammation and diabetes. Anti-inflammatory activity is evaluated through a protein denaturation assay using bovine serum albumin. SBC demonstrates significant anti-inflammatory activity, outperforming standard drug molecules, and exhibits concentration-dependent effects. In an α-amylase inhibitory assay, a vital enzyme in the digestive process related to diabetes, SBC shows remarkable inhibition, surpassing standard drug performance, especially at higher concentrations. Molecular docking studies suggest the compound's potential interactions with enzymes responsible for inflammation and diabetes. SBC displays strong binding energies and inhibition constants with α-amylase, indicating its suitability for diabetes-related studies. The synthesis and characterization of SBC, combined with its excellent anti-inflammatory and anti-diabetic activities, underscore its potential as a promising candidate for further biomedical research and therapeutic development.

A review study on green synthesis of chitosan derived schiff bases and their applications

Chitosan is a bio-degradable, bio-compatible, non-toxic, and renewable biopolymer. The reactive amino group of chitosan has gained importance because using these amino groups can help achieve the different types of structural modification in chitosan. Chemical modification of chitosan via imine functionalization results in the formation of a chitosan Schiff base. The present review covers the green synthesis of chitosan Schiff bases using non-conventional green methods such as microwave irradiation, green solvent, ultrasound irradiation, and one-pot synthesis. These methods are energy-efficient and greener versions of the conventional condensation methods. Scientists have paid significant attention to the chitosan Schiff base because of its unique properties and versatility. These molecules display various biological applications, including antioxidant, antimicrobial, anticancer, antibacterial, and anti-fungal. In addition to biological applications, chitosan Schiff base also has other applications like corrosion inhibition, catalysis, metal ion adsorption, and as a sensor. Available literature particularly shows the different methods for the synthesis of chitosan Schiff bases and their different applications. This review gives detailed insight regarding sustainable approaches to the synthesis of chitosan derived Schiff bases and their applications in various emerging fields.