Claisen-Schmidt Condensation Reaction Research Articles

Synthesis and Biological Applications of Coumarinyl-Chalcones

Abstract: This survey provides information on the synthesis and biological applications of coumarinylchalcones. Chalcones are unsaturated ketones involving the reactive keto-ethylenic group (CO-CH=CH). Chalcones are naturally abundant in many medical plants, including vegetables, fruits, and foods. Natural and synthetic chalcone compounds exhibit a broad spectrum of biological properties like anticancer, antiinflammatory, anti-HIV, antioxidant, antimalarial, and antimicrobial. Some conventional, microwave, and grinding techniques have been utilized for the synthesis of chalcones. Noteworthy, the Claisen-Schmidt condensation reaction remains the most popular and effective method for synthesis. It summarizes information about its synthetic methods as building blocks in some reactions like cyclization reactions and medical applications. This review article presents an overview of approaches and biological data for chalcones bearing a coumarin scaffold.

Sintesis Senyawa (2E,5E)-2,5-Bis(3,4-Dimetoksibenziliden) Siklopentanon Menggunakan Metode Microwave Assisted Organic Synthesis

The aims of this study are synthesize (2E,5E)-2,5-bis(3,4- dimethoxybenzylidine)cyclopentanone compound with variation of NaOH catalyst moles and determining the yield of (2E,5E)-2,5-bis(3,4-dimethoxybenzylidine) cyclopentanone compound that has been synthesized. The synthesize was carried out by reacting 5 mmol of cyclopentanone and 10 mmol of veratraldehyde using NaOH as catalyst with variations of 5, 10, 15, and 20 mmol and ethanol as solvent. This synthesize was proceeds via Claisen-Schmidt condensation reaction using microwave assisted organic synthesis method for 60 seconds. The products were characterized with TLC and TLC scanner, FTIR, and 1H-NMR. The research obtained products in the form of yellow powder with the characterization results showing that the compound is (2E,5E)-2,5-bis(3,4-dimethoxybenzylidine)cyclopentanone. The yield of (2E,5E)-2,5-bis(3,4-dimethoxybenzylidine)cyclopentanone compound produced by catalyst variations of 5, 10, 15, and 20 mmol were 71.75%; 60.44%; 118.42%; and 113.54% respectively.

The Synthesis of 2'-Hydroxychalcones under Ball Mill Conditions and Their Biological Activities.

Chalcones are polyphenols that belong to the flavonoids family, known for their broad pharmacological properties. They have thus attracted the attention of chemists for their obtention and potential activities. In our study, a library of compounds from 2'-hydroxychalcone's family was first synthesized. A one-step mechanochemical synthesis via Claisen-Schmidt condensation reaction under ball mill conditions was studied, first in a model reaction between a 5'-fluoro-2'-hydroxyacetophenone and 3,4-dimethoxybenzaldehyde. The reaction was optimized in terms of catalysts, ratio of reagents, reaction time, and influence of additives. Among all assays, we retained the best one, which gave the highest yield of 96% when operating in the presence of 1 + 1 eq. of substituted benzaldehyde and 2 eq. of KOH under two grinding cycles of 30 min. Thus, this protocol was adopted for the synthesis of the selected library of 2'-hydroxychalcones derivatives. The biological activities of 17 compounds were then assessed against Plasmodium falciparum, Leishmania donovani parasite development, as well as IGR-39 melanoma cell lines by inhibiting their viability and proliferation. Compounds 6 and 11 are the most potent against L. donovani, exhibiting IC50 values of 2.33 µM and 2.82 µM, respectively, better than the reference drug Miltefosine (3.66 µM). Compound 15 presented the most interesting antimalarial activity against the 3D7 strain, with IC50 = 3.21 µM. Finally, chalcone 12 gave the best result against IGR-39 melanoma cell lines, with an IC50 value of 12 µM better than the reference drug Dacarbazine (IC50 = 25 µM).

Synthesis, structure determination, molecular interaction, optical, thermal and anticancer activity studies, pharmacokinetic evaluation, and in-silico analysis of monocarbonyl curcumin derivative: An approach to drug discovery

Overseeing the diverse pharmacological traits of curcumin, a novel monocarbonyl based curcumin derivative (1-(4-ethylbenzoyl)-3, 5-bis ((E)-4-methoxybenzylidene) piperidin-4-one) [EMBP] was synthesized by Claisen-Schmidt condensation and Schotten-Baumann reaction procedures, and diffraction quality crystal was obtained by slow evaporation method. Geometrical parameters were calculated for the grown crystal by using the SCXRD technique. The non-covalent interactions like CH∙∙∙π, π∙∙∙π were visualized by Hirshfeld surfaces analysis. The contribution of various interactions towards the total Hirshfeld surface has been quantified by 2D fingerprint plot. The synthesized material is characterized for various optical and spectral properties through NMR, FT-Raman, FT-IR, UV–Vis, and PL spectra. The thermal stability and melting point of the material have been examined by TG/DTA analysis. The cytotoxic effect on the normal cell line HEK-293 was evaluated, and found that the compound is highly toxic. Anticancer activity on MCF-7 cell line of the compound was assessed and found to exhibit exceptional efficacy against cancerous cells. Results of molecular docking studies and evaluated ADMET properties clearly demonstrate that the synthesized material can be proposed as a promising medication for treating breast cancer but after an extensive biological and pharmaceutical research.

Synthesis, structural examination, molecular interaction analysis, invitro and insilico anticancer activity investigation of a new curcumin derivative: 1- (4 – chlorobenzoyl) - 3, 5 - bis ((E) - 4 - methoxybenzylidene) piperidin - 4 – one

The title material, C28H24ClNO4, was synthesized using the Claisen-Schmidt condensation reaction and Schotten-Baumann reaction methods and crystallized. Geometrical parameters were determined for the grown crystal using the Single Crystal X-Ray Diffraction (SCXRD) technique. The title compound has been characterized and anzalyzed for its optical properties via1H1 and 13C NMR, FT-Raman, and FT-IR, UV and PL spectra. The melting point and thermal stability have been investigated using TG/DTA thermograms.Hirshfeld surfaces were developed in order to observe and quantify short contacts, CH…π and π...π stacking interactions. To determine how various interactions influence the overall Hirshfeld surface, 2D fingerprint plots were created, and it was discovered that the H…H contact's contribution was the most significant. Cytotoxic effect on HEK293 cell lines was performed and found to be highly toxic. To determine the compound's efficacy as an anticancer agent, a research was conducted using MCF-7 cell lines. Molecular docking simulation revealed that the title material (ligand) fits well at the active site of the target protein with PDB ID: 1M17. Pharmacokinetic, and ADMET properties revealed that the compound is exceedingly orally active, and after further biological and pharmaceutical investigations, the compound can be recommended as a drug candidate.

Novel chalcone-based crown ethers: synthesis, characterization, antioxidant activity, biological evaluations, and wastewater remediation.

Macrocycles play a pivotal and indispensable role within the realms of both medicine and industry. In the course of our research endeavors, we have successfully synthesized five distinct macrocyclic chalcone entities, each showcasing remarkable biological and anti-oxidative properties. Furthermore, these compounds exhibit exceptional promise as potent agents for the removal of dyes in wastewater treatment processes. The synthesis of these key constituents was achieved through the judicious application of the Robinson ether synthesis and Claisen-Schmidt condensation reactions. The structures of compounds 1a-f and 2a-e were characterized by using analytical techniques such as FTIR, 1H NMR, 13C NMR, and DEPT 13C NMR spectroscopy. These macrocycles also underwent in vitro assessments to measure their antibacterial activity using the agar well diffusion method. The results revealed that the macrocyclics were more sensitive to Gram-positive than Gram-negative bacteria. For example, compound 2d exhibited an inhibition zone of 20 mm at 150 ppm. The antioxidant activity as determined via the DPPH method established that all tested compounds showed moderate radical-scavenging ability. Specifically, compound 2e (at 1000 ppm) exhibited antioxidant activity of 79% inhibition of radicals, in comparison to 90% for the standard ascorbic acid. The latter was demonstrated by using methylene blue as an adsorbate under simulated wastewater conditions. Outstandingly, the most effective compounds were 2d and 2c, which achieved removal rates of 96.54% and 92.37%, respectively, for methylene blue dye.

Recent Progress in Environmentally-Friendly Methods for Chalcone Synthesis

Abstract: Chalcones are important scaffolds in the field of medicinal chemistry due to the presence of α,β-unsaturated ketone functionality. They are usually synthesized by reacting an aldehyde with acetophenone in the presence of acid or base using the Claisen-Schmidt condensation reaction. Numerous chalcone derivatives have been developed due to the simplicity of their synthesis, and they have intriguing biological activity that has clinical implications for a range of disorders. The review article discusses the advancements made since 2005 for the synthesis of chalcones derivatives using environmentally friendly methods such as the use of green catalysts and solvents, ultrasonic radiation, microwave energy, and methodologies involving grinding in the absence of solvents.

SPECTRAL ELUCIDATION, ANTIMICROBIAL AND ANTIOXIDANT STUDY OF NEWLY SYNTHESIZED PYRAZOLINE DERIVATIVES

The preparation of Chalcones and Pyrazoline derivatives from different aromatic ketones and substituted aldehydes is detailed. Chalcones were produced by reacting aldehydes with substituted aromatic ketones, such as acetophenones, in the Claisen-Schmidt condensation reaction. Cyclohexenone derivatives are produced when ethyl aceto aromatic ketones undergo base-catalyzed cyclo-condensation to Chalcones under microwave radiation. The synthesized compounds are characterized using spectrum techniques from 1H NMR, 13C NMR, and IR. These are examined for their antioxidant qualities as well as their antibacterial action against Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Aspergillus flavus.

Exploring the engineered hierarchical MgO microspheres as a selective catalyst for the Claisen–Schmidt condensation reaction

Exploring the utilization of earth-abundant metal oxide for sustainable essential organic transformation for industrial applications.

Synthesis, Antimicrobial Activity and Dual Target Docking Studies of Novel 1-(5-Chloro-1-benzofuran-2-yl)-3-substituted Phenyl Prop-2-en-1-ones

This study involved synthesizing five novel derivatives of 1-(5-chloro-1-benzofuran-2-yl)-3-substituted phenyl prop-2-en-1-ones throughthe Claisen-Schmidt condensation reaction, using 5-chloro-2-acetyl benzofuran and aromatic aldehydes in the presence of base catalyst. The chemical structures of these compounds were confirmed by using IR spectroscopy, 1H NMR spectroscopy and mass spectrometry. Schrödinger docking simulations were employed to ascertain the binding affinity of the synthesized compounds to Mycobacterium tuberculosis enoyl-ACP reductase and Escherichia coli Topoisomerase IV. Subsequently, the anti-tubercular and in vitro antibacterial activities of the synthesized compounds were also investigated. Anti-tubercular efficacy was determined using the MABA method, while the antibacterial effectiveness was assessed against both Gram-positive and Gram-negative bacterial strains through the agar cup plate. The findings from these assays provide insights into the potential of these compounds as agents possessing anti-tubercular and antibacterial characteristics, thereby offering promising prospects for further investigation in the field of drug development.

Structural Elucidation, In vitro and In silico Biological Evaluations of New Fluorinated Chalcone Derivatives for Potential Antioxidant Activity

Abstract: The newly synthesized fluorinated chalcone derivatives are observed to possess antioxidant potential. Two new fluorinated chalcone compounds were effectively synthesized using the Claisen- Schmidt condensation reaction and were recrystallized using the slow evaporation method. The single crystal structure of the compounds was determined and refined through the X-ray single crystal diffraction method. All compounds were subjected to computational structural characterization and Hirshfeld surface analysis. The compounds were then further characterized through the Ultravioletvisible (UV-Vis) spectroscopic study. The chalcone derivatives were further analysed with biological experimentation and simulation such as in vitro antioxidant (DPPH) assay, molecular docking and in silico ADMET study. The crystal packing revealed that the molecules in the compounds were linked together through the intermolecular C—H···O and C—H···π interactions. Hirshfeld surface analysis validated the presence of intermolecular interactions in crystal packing. The UV-Vis spectroscopic study revealed that the absorption wavelength of the compounds that range from 421.79 to 428.98 nm was within the visible region with the energy gap value of 2.58 to 2.62 eV. The DPPH assay disclosed weak antioxidant activity of both compounds (-31 to 20 %, 10000 μg/mL) compared to the standard ascorbic acid (94.5 %, 50 μg/mL). The binding energy of the docked complex inside the target protein, 2CAG was within the range of -7.3 to -7.5 kcal/mol. In the silico model, SwissADME predicted that the two compounds have overall good drug-like properties. Different substituents, more planar configuration and high intramolecular interactions in the crystal packing played their role in increasing the antioxidant activities, binding energy and drug likeliness of the synthesized compounds.

One-Step, Low-Cost, Operator-Friendly, and Scalable Procedure to Synthetize Novel Tetrazolopyrimidinylbenzopyran-2-ones by Benign Protocol

Abstract: New coumarin chalcones 3j–p were conveniently obtained in high yields via Claisen-Schmidt condensation reaction, when acetyl coumarin 1 reacted with 3-aryl-1-phenyl pyrazole-4-carbaldehydes 2j–p in boiling ethanol in the presence of triethyl amine as a catalyst. Also, two synthetic pathways were afforded for the synthesis of novel tetrazolo[1,5-a]pyrimidinyl-2H-chromen-2-ones 5a-p. The first pathway is a multistep process including formation and separation of chalcones, which then were allowed to react with 5-aminotetrazole 4. While, the second pathway is a highly efficient one-pot three-component condensation reaction of 3-acetyl coumarin 1, aromatic aldehydes 2a-p and 5-aminotetrazole 4 under green and mild reaction conditions by using acetic acid (AcOH) as a catalyst and solvent. The molecular structure of products was established on the basis of their NMRs, IR and elemental analysis data. Solvent optimization was carried out in the reaction producing 3-(5-Phenyl-4,5-dihydrotetrazolo[1,5-a]pyrimidin-7-yl)-2H-chromen-2-one (5a). The advantages to using environmental-friendly acetic acid are simple operation, short reaction time, high efficient (97%), operationally facile and wide tolerance of starting materials. objective: The advantages of using environmental-friendly AcOH are simple operation, short reaction time, high efficient (97%), operationally facile and wide tolerance of starting materials.

Studies in the influence of D–π–A pyrenyl chalcone containing methoxy substitution as dye-sensitizer in DSSC

A pyrene based chalcone (PyMe) has been prepared by Claisen-Schmidt condensation reaction. The proposed structure was proceeded for characterization analysis of Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopic (FTIR) and Ultraviolet-Visible (UV-Vis) studies. The analysis of cyclic voltammetry (CV) performed has determined the appropriated position of HOMO and LUMO energy level for electron injection and dye regeneration in DSSC. The Field-Emission Scanning Electron Microscopy (FESEM) and Energy dispersive X-ray spectroscopy (EDX) study has confirmed the existence of PyMe based on the distribution and composition of the elements on the TiO2 layer, respectively. The Donor–π–Acceptor (D–π–A) structural chromophores with methoxy (-OCH3) attachment in PyMe has also contribute to the power conversion efficiency of DSSC.

Eco-friendly Cu/NiO nanoparticle synthesis: Catalytic potential in isatin-based chalcone synthesis for anticancer activity

Isatin (1H-indole-2,3‑dione) is a natural heterocyclic compound extracted from various plants and has biological activity as an anticancer agent. Chalcones with the addition of several functional groups (hydroxyl, carboxyl, phenyl, etc.) may become useful templates for the development of new anticancer agents. In this study, we have synthesized Cu/NiO nanoparticles using the sol-gel method involving annona muricata L leaf extract and used as catalysts for the synthesis of isatin-based chalcone. These compounds will be applied as anticancer agents against MCF-7 cancer cell. According to the characterization results using FT-IR, XRD, FESEM-EDS, the crystal size for Cu/NiO nanoparticles was 5.4566 nm and the particle size was 25.081 ± 8.422 nm with irregular spherical shapes. The synthesis of isatin based on chalcone using the reflux method refers to the claisen schmidt condensation reaction using 5% mmol Cu/NiO nanoparticles resulting in yields for each product of 50 % (product 1), 32.37 % (product 2), 24.29 % (product 3), 32.35 % (product 4), 50.86 % (product 5), and 69.88 % (product 6). The effectiveness of the six products against MCF-7 cancer cells can be seen from the IC50 values as follows product 1 (IC50 = 0.00157 µg/ml), product 2 (IC50 = 100.897 µg/ml), product 3 (IC50 = 81.991 µg/ml), product 4 (IC50 = 8107.54 µg/ml), product 5 (IC50 = 77.9291 µg/ml), product 6 (IC50 = 25.4521 µg/ml). Based on the IC50 value obtained, it shows that product 1 and product 6 have strong activity when compared to another product on against MCF-7 cancer cells.•Acetophenone as a simple ketone was modified to 2-acetylpyridine.•Modification was performed adding Cu/NiO nanoparticle as catalyst.•Final products exhibited anticancer activity (MCF-7).

Targeting AKT2 in MDA-MB-231 Cells by Pyrazole Hybrids: Structural, Biological and Molecular Docking Studies.

Pyrazolic hybrids appended with naphthalene, p-chlorobenzene, o-phenol and toluene have been synthesized using Claisen Schmidt condensation reaction of 1-benzyl-3,5-dimethyl-1H-pyrazole-4-carbaldehyde. All compounds were characterized by various spectroscopic techniques. Compound (E)-3-(1-benzyl-3,5-dimethyl-1H-pyrazol-4-yl)-1-(4-chlorophenyl)prop-2-en-1-one crystallizes in monoclinic crystal system with C2/c space group. These synthesized compounds were tested for cytotoxic activity and among these compounds 4b and 5a shows prominent cytotoxic activity against triple-negative breast cancer (TNBC) cells MDA-MB-231 with IC50 values 47.72 μM and 24.25 μM, respectively. Distinguishing morphological changes were noticed in MDA-MB-231 cells treated with pyrazole hybrids contributing to apoptosis action. To get more insight into cytotoxic activity, in silico molecular docking of these compounds were performed and the results suggested that (E)-3-(1-benzyl-3,5-dimethyl-1H-pyrazol-4-yl)-1-(p-tolyl)prop-2-en-1-one and 1-(1'-benzyl-5-(4-chlorophenyl)-3',5'-dimethyl-3,4-dihydro-1'H,2H-[3,4'-bipyrazol]-2-yl)ethan-1-one binds to the prominent domain of Akt2 indicating their potential ability as Akt2 inhibitor. Moreover, from in silico ADME studies clearly demonstrated that these compounds may be regarded as a drug candidate for sub-lingual absorption based on log p values (2.157-4.924). These compounds also show promising antitubercular activity. The overall results suggest that pyrazolic hybrids with substitution at less sterically hindered positions have appealing potent cytotoxic activity and antituberculosis activity due to which they may act as multidrug candidate.

Synthesis, In Vitro and In Silico Biological Studies of 1, 2, 3-Triazole-Furan Chalcone Hybrids

In the present investigation, we focused our interest to develop 1, 2, 3-triazolefuran chalcone hybrids along with their biological profile. The synthesis of target molecules involves sequence of reactions, namely diazotization, nucleophilic substitution, cycloaddition and finally, solvent-free Claisen–Schmidt condensation reaction. The biological profile of the synthesized compounds was carried out using prediction of activity spectra for substances and results revealed that the synthesized compounds may act as mild antimicrobial agents.

Synthesis, structural, spectral, thermal, and optical characterization of a new curcumin derivative: A promising material for NLO applications

A novel Curcumin derivative 1-(4-chlorobenzoyl)-3,5-bis((E)-3,4-dimethoxybenzylidene)piperidin-4-one (CDMBP) has been synthesized by Claisen-Schmidt condensation and Schotten-Baumann reaction methods. CDMBP single crystal was grown from acetone by slow evaporation method at ambient temperature. The crystal structure of the compound was derived by Single Crystal X-ray Diffraction studies (SCXRD). The title compound CDMBP was crystallized in a triclinic crystal system with a P ͞1 space group. NMR spectral analysis reveals the different types of carbon and proton in the molecular structure of the title compound. The modes of vibrations of different chemical groups were identified using FT-Raman and Fourier Transform Infrared spectral analysis (FTIR). Utilizing the UV–Vis spectrum, the cutoff wavelength and linear optical constants such as the band gap, extinction coefficient, and refractive index were calculated. The Photoluminescence spectrum (PL) has been studied and it shows a high-intensity peak at 504 nm and belongs to the green emission radiation region. Fluorescence profiling of the compound was done to get an outline of the emission features of the excited states with the emission decay mechanisms using Lifetime measurements. The third-order nonlinear optical property (NLO) of CDMBP was investigated in detail using a Z-scan technique with a He–Ne laser at 632.8 nm as a laser source. The nonlinear optical susceptibility (χ3), absorption coefficient (β), and refractive index (n) were calculated using transmittance data. The thermal stability of the grown crystal was investigated from the Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA).

Synthesis, in-vitro inhibition of cyclooxygenases and in silico studies of new isoxazole derivatives.

Isoxazole belongs to the class of five-membered heterocyclic compounds. The process of developing new drugs has significantly gained attention due to inadequate pharmacokinetic and safety attributes of the available drugs. This study aimed to design a new diverse array of ten novel isoxazole derivatives via Claisen Schmidt condensation reaction. In vitro COX-1/2 anti-inflammatory assay, in silico molecular docking of potent compounds, Molecular docking simulation, and SwissADME pharmacokinetic profile were investigated in this research. The in vitro COX-1 and COX-2 enzyme inhibitory assay showed that almost all the tested compounds exhibited anti-inflammatory effects whereas C6, C5, and C3 were found to be the most potent COX-2 enzyme inhibitors among the tested compounds and are good candidates for selective COX-2 inhibitors. In silico molecular docking studies coupled with molecular dynamic simulation has been done to rationalize the time-evolved mode of interaction of selected inhibitor inside the active pockets of target COX-2. The binding orientations and binding energy results also showed the selectivity of compounds towards COX-2. Physicochemical properties, pharmacokinetic profile, lipophilicity, water solubility, drug metabolism, drug-likeness properties, and medicinal chemistry of the synthesized isoxazole derivatives were assessed. The SwissADME (absorption, distribution, metabolism, and excretion) database was used to assess the physicochemical properties and drug-likeness properties of the synthesized isoxazole derivatives. All the compounds were shown high GI absorption except Compound 7 (C7). Compound 1 (C1) and Compound 2 (C2) were found to cross the blood-brain barrier (BBB). Lipinski's rule of five is not violated by any of the ten synthesized isoxazole derivatives. It was predicted with the SwissADME database that C2, C5, C6, C7, and C8 are potent inhibitors of cytochrome (CYP) subtype CYP-2C19. A subtype of CYP-2C9 was inhibited by C4 and C7. The medicinal chemistry of all the compounds C1-C10 showed no PAIN (Pan assay interference compounds) alerts. The improved gastrointestinal (GI) absorption and BBB permeability of C1 and C2 can provide a future prospective for new researchers in the medicinal field to investigate the compounds for the management of chronic diseases. The synthesized isoxazole compounds showed excellent in vitro COX-1/2 enzymes anti-inflammatory investigations, in silico studies, good physicochemical properties, and improved pharmacokinetic profile which will be further investigated via in vivo anti-inflammatory activities. Moreover, to further support our findings of the computational research and in vitro studies, an in-vivo pharmacokinetic profile is suggested in the future.

New Benzodihydrofuran Derivatives Alter the Amyloid β Peptide Aggregation: Strategies To Develop New Anti-Alzheimer Drugs.

Alzheimer's disease is a neurodegenerative disorder that is the leading cause of dementia in elderly patients. Amyloid-β peptide (1-42 oligomers) has been identified as a neurotoxic factor, triggering many neuropathologic events. In this study, 15 chalcones were synthesized employing the Claisen-Schmidt condensation reaction, starting from a compound derived from fomannoxine, a natural benzodihydrofuran whose neuroprotective activity has been proven and reported, and methyl aromatic ketones with diverse patterns of halogenated substitution. As a result, chalcones were obtained, with good to excellent reaction yields from 50 to 98%. Cytotoxicity of the compounds was assessed, and their cytoprotective effect against the toxicity associated with Aβ was evaluated on PC-12 cells. Out of the 15 chalcones obtained, only the 4-bromo substituted was cytotoxic at most tested concentrations. Three synthesized chalcones showed a cytoprotective effect against Aβ toxicity (over 37%). The 2,4,5-trifluoro substituted chalcone was the most promising series since it showed a cytoprotective impact with more than 60 ± 5% of recovery of cellular viability; however, 3-fluoro substituted compound also exhibited important values of recovery (50 ± 6%). The fluorine substitution pattern was shown to be more effective for cytoprotective activity. Specifically, substitution with fluorine in the 3,5-positions turned out to be particularly effective for cytoprotection. Furthermore, fluorinated compounds inhibited the aggregation rate of Aβ, suggesting a dual effect that can be the starting point of new molecules with therapeutic potential.

Synthesis of propenone-linked covalent organic frameworks via Claisen-Schmidt reaction for photocatalytic removal of uranium

The type of reactions and the availability of monomers for the synthesis of sp2-c linked covalent organic frameworks (COFs) are considerably limited by the irreversibility of the C=C bond. Herein, inspired by the Claisen-Schmidt condensation reaction, two propenone-linked (C=C–C=O) COFs (named Py-DAB and PyN-DAB) are developed based on the base-catalyzed nucleophilic addition reaction of ketone-activated α-H with aromatic aldehydes. The introduction of propenone structure endows COFs with high crystallinity, excellent physicochemical stability, and intriguing optoelectronic properties. Benefitting from the rational design on the COFs skeleton, Py-DAB and PyN-DAB are applied to the extraction of radionuclide uranium. In particular, PyN-DAB shows excellent removal rates (>98%) in four uranium mine wastewater samples. We highlight that such a general strategy can provide a valuable avenue toward various functional porous crystalline materials.