Imine Derivatives Research Articles

3-Formylindole-based chitosan Schiff base polymer: Antioxidant and in vitro cytotoxicity studies on THP-1 cells

Two imine derivatives of chitosan (i-CTs), namely 2FCT and 5MCT, were synthesized by reacting chitosan (CT) with 2-(3-formyl-1H-indol-1yl)acetonitrile (2F), and 5-methoxyindole-3-carbaldehyde (5M), respectively. The antimicrobial evaluation of i-CTs exhibited stronger inhibition effect against Staphylococcus aureus, Escherichia coli and Candida albicans. The antioxidant activity of 2FCT and 5MCT showed strong scavenging ability with IC50 2.31 and 6.92 μg/mL, respectively. The results of in vitro cytotoxicity of 2FCT and 5MCT examined using human monocyte leukemia (THP-1) cells indicate no cytotoxic effect on host cells and the value of cell viability was found to be 87.08 and 84.47%, respectively. Measurement of intracellular Reactive Oxygen Species (ROS) production by flow cytometry analysis revealed that the 2FCT and 5MCT reduced the ROS generation by 83 and 43%, respectively. In summary, these findings show that i-CTs synthesized to be promising biomaterial for biomedical applications such as wound healing.

Progress of 3-aminopyridine-based amide, urea, imine and azo derivatives in supramolecular gelation

Supramolecular gels derived from low molecular weight gelators are considered to be fascinating soft and smart materials. Gelators of this class form gel networks involving noncovalent interactions and show various applications in many areas. The structural softness and the arrangement of the gelator molecules in the aggregated state have the collaborative effect to intensify the properties of the molecules for their potential applications in material chemistry. Of the various properties, stimulus responsibility is a desired property of supramolecular gel that finds profound application in sensing. In this review, a comprehensive summary of the work on 3-aminopyridine-based amide, urea, imine and azo gelators of different architectures indicating their different uses in supramolecular chemistry has been focused.

Sensitive 1,1-dicyanovinyl push-pull dye for primary amine sensing in solution by fluorescence

1,1-dicyanovinyl push-pull dye PTTCN undergoes rapid and reversible aza-Michael addition with volatile primary aliphatic amines in solution in DMSO, yielding highly fluorescent imine derivatives. This reaction is accompanied by a dramatic colour change as well as a strong increase in fluorescence (1200-fold increase) allowing sensitive turn-on detection of primary amine in solution. In the solid state, PTTCN is emissive and reaction with primary amine vapours results in a shift in fluorescence and a possible ratiometric detection of primary amines. The selectivity is excellent for primary amines over secondary, tertiary and aromatic amines as well as over thiols and fluorescence spectroscopy allows to discriminate between primary amines and other nitrogen nucleophiles such as hydrazine and ammonia. Finally, we show as proof-of-concept that the fluorescence turn-on reaction can be used in response to the vapours of volatile amines released during food spoilage.

Shedding Light on the Synthesis, Crystal Structure, Characterization, and Computational Study of Optoelectronic Properties and Bioactivity of Imine derivatives.

Two imine compounds named as (E)-2-(((3,4-dichlorophenyl)imino)methyl)phenol (DC2H) and (E)-4-(((2,4-dimethylphenyl)imino)methyl)phenol (DM4H) are synthesized, and their crystal structures are verified using the single-crystal X-ray diffraction (XRD) technique. The crystal structures of the compounds are compared with the closely related crystal structures using the Cambridge Structural Database (CSD). The crystal packing in terms of intermolecular interactions is fully explored by Hirshfeld surface analysis. Void analysis is carried out for both compounds to check the strength of the crystal packing. Furthermore, a state-of-the-art dual computational technique consisting of quantum chemical and molecular docking methods is used to shed light on the molecular structure, optoelectronic properties, and bioactivity of indigenously synthesized compounds. The optimized molecular geometries are compared with their counterpart experimental values. Based on previous reports of biofunctions of the indigenously synthesized imine derivatives, they are explored for their potential inhibition properties against two very crucial proteins (main protease (Mpro) and nonstructural protein 9 (NSP9)) of SARS-CoV-2. The calculated interaction energy values of DC2H and DM4H with Mpro are found to be −6.3 and −6.6 kcal/mol, respectively, and for NSP9, the calculated interaction energy value is found to be −6.5 kcal/mol. We believe that the current combined study through experiments and computational techniques will not only pique the interest of the broad scientific community but also evoke interest in their further in vitro and in vivo investigations.

Selective Encapsulation and Unusual Stabilization of cis-Isomers by a Spherical Polyaromatic Cavity.

To explore new cavity functions, we herein employed cis-trans stereoisomers with a N=N, C=C, or C=N unit as guest indicators for a polyaromatic capsule. Thanks to the rigid, spherical cavity with a diameter of ∼1 nm, azobenzene and stilbene derivatives are quantitatively encapsulated by the capsule with 100 % cis-selectivity in water. The isomerization of the cis-azo compound is suppressed against heat and light in the cavity, due to the confinement effect. Furthermore, C,N-diphenyl imine derivatives are quantitatively encapsulated by the capsule in water and adopt an otherwise unstable cis-form. The polyaromatic cavity suppresses the hydrolysis of the imines in water, even at elevated temperature, due to the shielding effect. Accordingly, the properties of the cis-trans isomers could be largely altered through supramolecular manipulation.

Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides.

In this work, the decomposition of a prototypical azide, isopropyl azide, both in the ground and excited states, has been investigated through the use of multiconfigurational CASSCF and MS-CASPT2 electronic structure approaches. Particular emphasis has been placed on the thermal reaction starting at the S0 ground state surface. It has been found that the azide thermally decomposes via a stepwise mechanism, whose rate-determining step is the formation of isopropyl nitrene, which is, in turn, the first step of the global mechanism. After that, the nitrene isomerizes to the corresponding imine derivative. Two routes are possible for such a decomposition: (i) a spin-allowed path involving a transition state; and (ii) a spin-forbidden one via a S0/T0 intersystem crossing. Both intermediates have been determined and characterised. Their associated relative energies have been found to be quite similar, 45.75 and 45.52 kcal mol-1, respectively. To complete this study, the kinetics of the singlet and triplet channels are modeled with the MESMER (Master Equation Solver for Multi-Energy Well Reactions) code by applying the RRKM and Landau-Zener (with WKB tunnelling correction) theories, respectively. It is found that the canonical rate-coefficients of the singlet path are 2-orders of magnitude higher than the rate-coefficients of the forbidden reaction. In addition, the concerted mechanism has been investigated that would lead to the formation of the imine derivative and nitrogen extrusion in the first step of the decomposition. After a careful analysis of CASSCF calculations with different active spaces and their comparison with single electronic configuration methods (MP2 and B3LYP), the concerted mechanism is discarded.

Design, synthesis and antimicrobial studies of novel imine derivatives of 2-(6H-indolo[2,3-b]quinoxalin-6-yl)-1-phenylethan-1-ones

Design, synthesis and antimicrobial studies of novel imine derivatives of 2-(6H-indolo[2,3-b]quinoxalin-6-yl)-1-phenylethan-1-ones

Isothiourea-catalyzed formal enantioselective conjugate addition of benzophenone imines to β-fluorinated α,β-unsaturated esters.

The isothiourea-catalyzed formal enantioselective conjugate addition of 2-hydroxybenzophenone imine derivatives to α,β-unsaturated para-nitrophenyl esters has been developed. Investigations of the scope and limitations of this procedure showed that β-electron withdrawing substituents within the α,β-unsaturated ester component are required for good product yield, giving rise to a range of β-imino ester and amide derivatives in moderate to good isolated yields with excellent enantioselectivity (20 examples, up to 81% yield and 97 : 3 er).

Urease inhibitory kinetics, molecular docking, SAR and ADME studies of imine analogues

A series of synthesized imine derivatives (3a–m), including thio-semicarbazone, semicarbazone, thiazole and oxazole functional moieties, were examined for in vitro urease inhibition activity.

Synthesis, Characterization and Biological Evaluation of Some Novel Azo-Imine Compounds

The oxidative cyclization of thiosemicarbazone (III) synthesized from reaction between substituted aryl aldehydes (I) with thiosemicarbazide (II) was done using ferric chloride as oxidative agent to get 2-amino-5-phenyl-1,3,4-thiadiazole (IV). 2-Amino-5-phenyl-1,3,4-thiadiazole was introduced in condensation reactions with substituted aldehydes to obtain benzylidene imine derivatives (VI)1-5. Further these were treated with sulphanilic acid to give new 2-{[5-phenyl-1,3,4-thiadiazole-2-imino] substituted benzene}diazenyl benzene sulfonic acid derivatives (VII)1-5. These derivatives were further characterized by FT-IR, 1H NMR and 13C NMR spectral studies and were screened for antibacterial, antifungal and antioxidant activities.

Cobalt-catalyzed C(sp2)-H bond imination of phenylalanine derivatives.

Herein we report the cobalt-catalyzed, picolinamide-directed C-H bond imination protocol of phenylalanine derivatives using isocyanides and a Co(dpm)2 catalyst. A wide range of functional groups were tolerated under the reaction conditions, yielding imines in high yields. The obtained imine products can easily be transformed to 1-aminoisoquinoline derivatives under reductive conditions, providing an attractive alternative to already existing methodologies. The control experiments indicated that C-H activation might occur via an electrophilic pathway.

Supramolecular catalysis in confined space: making the pyrogallol[4]arene capsule catalytically active in non-competitive solvent

The confined space inside the hexameric pyrogallol[4]arene capsule (CP6) has been exploited for the catalysis of the 1,3-dipolar cycloaddition (1,3-DC) between the proline-based iminium derivative I and nitrone 3, in the presence of the non-competitive benzene solvent.

Imine resveratrol analogs (IRAs): The strong antioxidant that can protect lymphocytes from oxidative damage.

Imine resveratrol analogs (IRAs) are promising new agents that can have higher positive effects and, simultaneously, lower negative properties than resveratrol. In this study,three imine hydroxy derivatives (2-((4-hydroxyphenylimino) methyl) phenol [IRA1], 3-((4-hydroxyphenylimino) methyl) phenol [IRA2], and 4-((4-hydroxyphenylimino) methyl) phenol [IRA3]) were prepared and tested in several biological assays. They performed superior to resveratrol in several antioxidant and biological assays, showing high antioxidant capacity and low genotoxicity. Ferric reducing antioxidant power assay (FRAP) and hydroxyl radicals scavenging assay revealed good Fe3+ to Fe2+ reduction and strong inhibition of hydroxyl radical formation, respectively. High dosage (1 mmol/dm3 ) of IRA2 and IRA3 did not cause genotoxicity in human lymphocytes. Moreover, lymphocytes pretreated with all three IRAs accumulated only very few DNA breaks induced by H2 O2 than lymphocytes pretreated with resveratrol. Additionally, the number of detected DNA breaks appearing after removal of damaged DNA bases, 8-oxo-7,8-dihydroguanine (8-oxoG), did not dramatically increase in lymphocytes treated with IRA2. Thus, we concluded that IRAs, especially IRA2, are strong antioxidants with the ability to protect lymphocytes from oxidative damage.

In vitro α-glucosidase and α-amylase inhibitory potential and molecular docking studies of benzohydrazide based imines and thiazolidine-4-one derivatives

Benzohydrazide based imine derivatives (1c-16c) and thiazolidine-4-one derivatives (1d-16d) were synthesized and characterized with different spectroscopic techniques i.e. HREI-MS, 1HNMR and 13CNMR. The synthesized analogs were examined for antidiabetic potential and hence evaluated against α-glucosidase and α-amylase enzyme. Benzohydrazide based imine derivatives showed outstanding α-glucosidase inhibition ranging from 5.60 ± 0.30 to 38.10 ± 0.30 µM when compared with acarbose (IC50 = 38.45 ± 0.80 µM). Compound 5c (IC50 = 5.60 ± 0.30 µM) has m/p-dihydroxyl groups at phenyl ring while compound 15c (IC50 = 7.30 ± 0.10 µM) has one p‑hydroxyl group present at phenyl ring were most potent in the imine series. Molecular docking study further support that hydrogen bonding is predominant. Thiazolidin-4-one derivatives (1d-16d) were screen against α-amylase enzyme and were found to show excellent potential with IC50 values ranging from 0.40 ± 0.05 to 22.11 ± 1.20 µM when compared with standard acarbose (IC50 = 0.91 ± 0.20 µM). The most potent analog in the series was 5d (IC50 = 0.40 ± 0.05 µM) when compared with standard. Molecular docking study was carried out for active site determination and to rationalize the activities of the active compounds.

An efficient synthesis of furan-3(2H)-imine scaffold from alkynones.

A novel efficient method to generate spiro furan-3(2H)-imine derivatives is established by the reaction between the α,β-unsaturated ketones and aniline derivatives. The reaction involves 1,4- addition of aniline followed by the subsequent intramolecular cyclization mediated by tertiary alcohol to produce the furan-3(2H)-imine. All the synthesized compounds are characterized using nuclear magnetic resonance and high-resolution mass spectrometry (HRMS).

Application of Rh(I)/Bicyclo[2.2.1]heptadiene Catalysts to the Enantioselective Synthesis of Chiral Amines.

The development of efficient synthetic methods for accessing enantioenriched α-chiral amines is of great importance in the disciplines of medicinal and synthetic organic chemistry. Enantioselective Rh-catalyzed 1,2-addition reactions to activated imine derivatives are regarded as useful protocols for forming α-chiral amines. This personal account outlines our efforts to develop chiral bicyclo[2.2.1]heptadiene ligands for Rh-catalyzed asymmetric additions of various organoboron reagents to a wide range of imine derivatives. Transformations of the thus-obtained adducts into known natural products or molecules of pharmaceutical importance serve to confirm their synthetic usefulness.

Synthesis, In Vitro, and In Silico Analysis of the Antioxidative Activity of Dapsone Imine Derivatives.

Dapsone (DDS) is an antibacterial drug with well-known antioxidant properties. However, the antioxidant behavior of its derivatives has not been well explored. In the present work, the antioxidant activity of 10 dapsone derivatives 4-substituted was determined by an evaluation in two in vitro models (DPPH radical scavenging assay and ferric reducing antioxidant power). These imine derivatives 1–10 were obtained through condensation between DDS and the corresponding aromatic aldehydes 4-substuited. Three derivatives presented better results than DDS in the determination of DPPH (2, 9, and 10). Likewise, we have three compounds with better reducing activity than dapsone (4, 9, and 10). In order to be more insight, the redox process, a conceptual DFT analysis was carried out. Molecular descriptors such as electronic distribution, the total charge accepting/donating capacity (I/A), and the partial charge accepting/donating capacity (ω+/ω−) were calculated to analyze the relative donor-acceptor capacity through employing a donor acceptor map (DAM). The DFT calculation allowed us to establish a relationship between GAPHOMO-LUMO and DAM with the observed antioxidant effects. According to the results, we concluded that compounds 2 and 3 have the lowest Ra values, representing a good antioxidant behavior observed experimentally in DPPH radical capturing. On the other hand, derivatives 4, 9, and 10 display the best reducing capacity activity with the highest ω− and Rd values. Consequently, we propose these compounds as the best antireductants in our DDS imine derivative series.

Synthesis , Identification And Evaluation Of Antibacterial Activity For Some New Heterocyclic Derivatives From 4-Methoxy-2-Nitroaniline

This research involved synthesis. novel heterocyclic derivatives (quinazoline and thiazinone) derivatives , this compounds prepared from starting react (4-methoxy-2-nitroaniline) with 2,4-dimethoxyacetophenone to gate azo derivative (A) , (A) interact with aromatic amine derivatives to produce imine compounds (B1-B2), imine derivatives interact with (anthranilic acid , 2-mercaptobenzoic) to get heterocyclic derivatives quinazoline (C1-C2) and thiazinone (D1-D2 ) . All these compound characterized by13 C-NMR , FT-IR , 1HMNR . Then that,we studies the,biological,properties for,all heterocyclic derivatives,to,ward.two different kindof bacteria.

Transition-Metal-Catalyzed Diarylation of Isocyanides with Triarylbismuthines for the Selective Synthesis of Imine Derivatives.

The transition-metal-catalyzed diarylation of isocyanides with triarylbismuthines was investigated in detail, and rhodium catalysts such as [RhCl(nbd)]2 were found to selectively afford N-alkyl diaryl ketimines. On the other hand, palladium-catalyzed diarylation proceeded with the incorporation of two molecules of isocyanide, preferentially yielding N,N’-dialkyl or N,N’-diaryl α-diimines. In addition, a cascade synthesis of 2,3-diarylquinoxalines starting from the palladium-catalyzed diarylation of isocyanides with triarylbismuthines was successfully achieved.

Electronic Lability of Quinonoid‐Bridged Dinuclear 3 d‐Metal Complexes with Tetradentate N‐Donor Bases

AbstractBimetallic coordination compounds prone to spin‐state‐switching rearrangements via spin‐crossover or valence tautomerism mechanisms are of ongoing interest due to their unique magnetic characteristics. Dinuclear transition metal (Cr, Mn, Fe, Co, Ni, Cu) complexes with redox‐active bridging ligands (tetraoxolenes and their imine derivatives, di‐o‐quinones bearing linker groups) and tetradentate nitrogen‐containing bases (tetraazacyclotetradecane, tris(2‐pyridylmethyl)amine and N,N′‐dialkyl‐2,11‐diaza[3.3]‐(2,6)pyridinophane derivatives) are described from the viewpoint of their electronic structure and magnetic properties. The present review summarizes data on comprehensive investigations of bi‐ and polystable species of such structural architectures, which might be valuable for the chemists and materials scientists involved in the creation of new promising magnetic materials − building blocks for electronic devices of future generations.