Ether Derivatives Research Articles

Degradable Glycopolyester-like Nanoparticles by Radical Ring-Opening Polymerization.

A small library of degradable polyester-like glycopolymers was successfully prepared by the combination of radical ring-opening copolymerization of 2-methylene-1,3-dioxepane as a cyclic ketene acetal (CKA) with vinyl ether (VE) derivatives and a Pd-catalyzed thioglycoconjugation. The resulting thioglycopolymers were formulated into self-stabilized thioglyconanoparticles, which were stable up to 4 months and were enzymatically degraded. Nanoparticles and their degradation products exhibited a good cytocompatibility on two healthy cell lines. Interactions between thioglyconanoparticles and lectins were investigated and highlighted the presence of both specific carbohydrate/lectin interactions and nonspecific hydrophobic interactions. Fluorescent thioglyconanoparticles were also prepared either by encapsulation of Nile red or by the functionalization of the polymer backbone with rhodamine B. Such nanoparticles were used to prove the cell internalization of the thioglyconanoparticles by lung adenocarcinoma (A549) cells, which underlined the great potential of P(CKA-co-VE) copolymers for biomedical applications.

Amino ether analogues of 4,4′-dihydroxy-3-methoxy-6,7′-cyclolignan and their activity against drug-resistant bacteria

Larrea tridentata antibacterial lignan 4,4′-dihydroxy-3-methoxy-6,7′-cyclolignan ( 1 ) was derivatized to obtain eleven new amino ether derivatives ( 2 A - 12 C ). The structural elucidation of compounds was performed by analysis of 1D- and 2D NMR spectral data and HRESIMS. The antibacterial activity of compounds was determined against nine drug-resistant bacteria and two strains of Mycobacterium tuberculosis (sensitive ATCC 27294 H37Rv and drug-resistant G122). Results showed that all derivatives were devoid of activity towards six gram-negative clinical isolates assayed. However, seven derivatives displayed antibacterial activity against three gram-positive drug-resistant bacteria. Further, enhancement of antibacterial activity was only observed for the compounds 2 A and 10 C - 12 C (MIC of 12.5 µg/mL) which were two-fold more active than the starting material 1 against vancomycin-resistant Enterococcus faecium . All derivatives, except compound 9 B , showed antitubercular activity against both M. tuberculosis strains. Interestingly, all the compounds, except for 2 A and 11 A , were more active than the starting material 1 (MIC of 50 µg/mL). Compound 4 C was the only compound as active as the positive control ethambutol against the drug-resistant strain M. tuberculosis G122 (MIC of 6.25 µg/mL). In addition, the derivative 7 C was the most active compound against the sensitive strain M. tuberculosis H37Rv (MIC of 6.25 µg/mL) • Aminoether analogues of 4,4′-dihydroxy-3-methoxy-6,7′-cyclolignan were synthesized. • The antibacterial activity of the compounds was determined. • 4 C was as active as the control drug ethambutol against a multidrug resistant Mtb strain.

The inverse-electron demand Diels–Alder reaction of tetrazines with cyclic enol ethers

Inverse electron-demand Diels–Alder additions (iEDDA) between 1,2,4,5-tetrazines and suitable unsaturated dienophiles such as olefins, alkynes, or enol ethers provide facile access to pyridazines. Herein the use of cyclic enol ether derivatives for preparing pyridazines bearing 2-hydroxyethyl, 3-hyproxypropyl, and 3-oxopropyl substituents at the 4-position is disclosed and second order rate constants for the reactions with 2,3-dihydrofuran, 3,4-dihydro-2H-pyran, and 2-methoxy-3,4-dihydro-2H-pyran are presented.Graphical abstract

Synthesis of Bifunctional Tris‐Dendrimers Conjugated with Ibuprofen and Naproxen

AbstractWe report the synthesis of bifunctional AB2C dendrimers with tris(hydroxymethyl)‐aminomethane (Tris) conjugates with ibuprofen or naproxen within the interior and hydroxy groups on the periphery. Their postfunctionalization was investigated utilizing triethylene glycol monomethyl ether derivative. All the Tris‐dendrimers were characterized by 1H, 13C NMR in one and two dimensions. In addition, the anticancer activity tests showed that the conjugates of first generation with ibuprofen were active against human prostate cancer PC‐3 and human lung adenocarcinoma SKLU‐1 cancer cells. The conjugates of second generation with ibuprofen were less active than the first generation. The first generation naproxen conjugates were active against four cancer cell lines, and the second generation with naproxen were less active than the first generation. The conjugate of first generation with naproxen showed high anticancer activity, like the activity of cisplatin, but less toxic against healthy COS‐7 cells.

Tetradentate copper complex supported on boehmite nanoparticles as an efficient and heterogeneous reusable nanocatalyst for the synthesis of diaryl ethers

In this work boehmite nanoparticles (BNPs) were prepared through addition of aqueous solution of NaOH to solution of Al(NO3)3·9H2O. Then, the surface of BNPs was modified by (3-chloropropyl)trimethoxysilane (CPTMS) and further tetradentate ligand (MP-bis(AMP)) was anchored on its surface. At final step, a tetradentate organometallic complex of copper was stabilized on the surface of modified BNPs (Cu(II)-MP-bis(AMP)@boehmite). These obtained nanoparticles were characterized using SEM imaging, WDX, EDS, AAS and TGA analysis, BET method, FT-IR spectroscopy, and XRD pattern. In continue, the catalytic activity of Cu(II)-MP-bis(AMP)@boehmite has been used as a much efficient, reusable and hybrid of organic–inorganic nanocatalyst in the synthesis of ether derivatives through C–O coupling reaction under palladium-free and phosphine-free conditions. Cu(II)-MP-bis(AMP)@boehmite catalyst has been recovered and reused again for several times in the synthesis of ether derivatives.

Four new diphenyl ether derivatives from a mangrove endophytic fungus Epicoccum sorghinum.

Four new diphenyl ethers, named epicoccethers K-N (1-4), were purified from the fermentation medium of a fungus Epicoccum sorghinum derived from Myoporum bontioides, and identified through HR-ESI-MS and NMR spectral analysis. Except that compound 1 showed moderate antifungal activity against Penicillium italicum and Fusarium graminearum, the other three compounds showed stronger activity against them than triadimefon. All of them showed moderate or weak antibacterial activity towards Staphylococcus aureus and Escherichia coli with O6 and O78 serotypes except that 3 was inactive to E. coli O6.

Application of Thiourea/Halogen Bond Donor Cocatalysis in Metal-Free Cationic Polymerization of Isobutyl Vinyl Ether and Styrene Derivatives

Application of Thiourea/Halogen Bond Donor Cocatalysis in Metal-Free Cationic Polymerization of Isobutyl Vinyl Ether and Styrene Derivatives

Taming the radical cation intermediate enabled one-step access to structurally diverse lignans

Lignans, in spite of their structural diversity, are all biosynthetically derived from coniferyl alcohol. We report herein a divergent synthesis of lignans from biomass-derived monolignols in a short synthetic sequence. Blue LED irradiation of a dichloromethane solution of dicinnamyl ether derivatives in the presence of Cu(TFA)2, an alcohol (2.0 equiv) and a catalytic amount of Fukuzumi’s salt affords the C7-alkoxylated aryltetralin cyclic ethers. Increasing the amount of alcohol under otherwise identical conditions diverts the reaction course to furnish the C7,C7’-dialkoxylated dibenzyltetrahydrofurans, while replacing Cu(TFA)2 with diphenyl disulfide (PhSSPh) provides selectively the C7-monoalkoxylated dibenzyltetrahydrofurans. Aza-, thia- and carba-analogues of lignans are equally accessible by simply changing the tethering atom of the allylic alcohols. Concise total syntheses of aglacins A, E, F, brassilignan, and dehydrodimethylconidendrin are documented featuring these transformations.

Unprecedented Rearrangement of β-Difluoroboryloxy Ethers: A Route to C-2 Alkyl-chromenones

AbstractThe addition of boron trifluoride etherate (BF3·OEt2) to allenic ketones has led to the isolation of the isolated boron difluoride enolates. The single-crystal structure of boron enolate has been solved. The unprecedented C1–C10 migration of (Z)-β-difluoroboryloxy ether derivatives is observed to deliver rearranged phenol derivatives which are functionalized to C-2 alkyl-chromenones. Interestingly the isolated boron enolates have exhibited significant anticancer properties.

Site-Selective Spin-Probe with a Photocleavable Macrocyclic Linker for Measuring the Dynamics of Water Surrounding a Liposomal Assembly

Abstract There is a growing interest in the behavior of water on the hydration layer of a soft matter surface in order to develop wet materials that can function in an aqueous environment and to increase the understanding of complex biological phenomena. Dynamic nuclear polarization (DNP), which increases the sensitivity of nuclear magnetic resonance (NMR) by enhancing the magnetization of nuclear spin with the magnetization of electron spin, has recently attracted attention as a method to measure the dynamics of water of hydration. The design of functional spin probes is expected to provide on-demand measurements. In this study, we report the results of an in-situ, site-selective measurement method of water surrounding liposomes using a photolyzable macrocycle. We succeeded in measuring the difference in water dynamics at two different regions around the liposomal membrane of the same sample by the photocleavage of an o-nitrobenzyl ether derivative.

Synthesis and studies of antimicrobial activity of azomethine crown ether derivatives and their copper complexes

Synthesis and studies of antimicrobial activity of azomethine crown ether derivatives and their copper complexes

Homogeneous Etherification Modification of Chitosan and Preparation of High-Strength Hydrogel

At present, the ocean as a treasure house of human development resources has attracted widespread attention. Chitin is the most abundant biomass resource in the ocean, and it is also a natural macromolecule second only to cellulose in nature. Its deacetylated product, chitosan, is not only easy to modify physically and chemically, but can be processed into various forms and has excellent properties. Biocompatibility, biodegradability, antibacterial, tissue adhesion and other biological activities. Derivatization reactions are often used to improve the properties of chitosan and give it new structures and functions.In this paper, a series of chitosan ether derivatives were synthesized using alkali/urea aqueous solution as the solvent and homogeneous etherification reaction medium of chitosan, and their structures and properties were characterized. Then, chitosan and quaternized chitosan are dissolved in the acrylic acid monomer aqueous solution, and the chitosan/polyacrylic acid and quaternized high-strength polyelectrolyte composite hydrogel (PEC) are obtained by in-situ polymerization. Finally, the above-mentioned composite hydrogel is treated with Ag+ to obtain the ultra-high strength of the dual interaction of static electricity and coordination bonds, and at the same time a physical cross-linked hydrogel (DPC) with anti-fatigue. The chitosan-based hydrogel with excellent mechanical properties has good application prospects in articular cartilage, wound dressings, bionic stents and the like.

Design, synthesis, and fungicidal activities of novel ethylenediamine bridged thiazole derivatives containing oxime ether or oxime ester moieties

AbstractTo study the influence of changing the piperidine ring on the fungicidal activity, at the same time based on the successful experience of opening the oxazoline ring, a series of novel ethylenediamine bridged thiazole derivatives containing oxime ether and oxime ester moieties were designed, synthesized, and first evaluated for their fungicidal activities against phytophthora capsaicae in vitro. The bioassays results showed that the target compounds possessed moderate fungicidal activities against phytophtho‐ra capsaicae. Compound 28b showed 53.6% fungicidal activity at 50 μg/ml. Oxime ether and oxime ester derivatives showed the similar level of activities. However, the activities of these compounds were lower than that of oxathiapiprolin, suggesting the piperidine ring was essential to maintain the fungicidal activities of these compounds. For the oxime ether derivatives, 16b, 22a, 25b, and 28b, the substituents on ethylenediamine have certain influence on the activity. Increasing the chain length of substituents is beneficial to the fungicidal activity. Meanwhile, these compounds were tested their fungicidal activities against other 9 fungi, and these compounds showed broad spectrum fungicidal activities. Some compounds exhibited more than 70% fungicial activities against specific fungi.

Discovering ester and ether derivatives of luminol as advanced chemiluminescence probes

A variety of luminol derivatives with N- and O-substitution have been synthesized with broad functional group tolerance. O-esterification has been demonstrated for the first time as a promising way to prepare enhanced CL reagents for sensing hemin, bloodstain and horseradish peroxidase (HRP). The most effective analogue with a deuterated acetyl group exhibited greater potential than luminol for bloodstain imaging and HRP imaging in western blotting (WB). In addition, O-etherification can greatly suppress CL signal that has been applied to design a CL probe for β-glucosidase (β-Glu). This study offers important and useful information regarding the luminol modification and shows great potential to use O-substituted analogues for enhanced CL analysis.

Thorough investigation of non-volatile substances extractible from inner coatings of metallic cans and their occurrence in the canned vegetables

Since the decline of the use of bisphenol A, the chemistry of the varnishes and coatings which are applied to the inner surfaces of metallic food contact materials is poorly documented. We hypothesised that can coatings are now diverse and bring forth various non-intentionally added substances (NIAS) to be described. Investigating complex components such as NIAS requires demanding non-targeted approaches. We investigated the coatings of 12 vegetable cans from the French market. More than 125 substances were pinpointed, among them 84 oligoester combinations from 8 diols and 4 diacids. Thus, oligoesters were the dominant family. Additives such as epoxidised soybean oil, bisphenol A diglycidyl ether and benzoguanamine derivatives and phenol-formaldehyde oligomers were also identified. A software for exploring databases of theoretical combinations of polyester and phenol-formaldehyde resin components (NIAS-db 1.0) was made available. The stepwise organic synthesis of native and deuterated combinations of neopentyl glycol and isophthalic acid (4 and 8 units, linear and cyclic) enabled a higher confidence level and monitoring in vegetable extracts. Migration of oligoesters averaged 330 µg/kg in the drained vegetables (43–1600 µg/kg). This study sheds light on the need to fulfil a proper risk assessment on this NIAS family (exposure and hazard characterisation).

Cobalt-Catalyzed Direct Aminocarbonylation of Ethers: Efficient Access to α-Amide Substituted Ether Derivatives.

Ethers are of central importance in the fields of biomass, energy, and organic chemistry. Herein, a novel cobalt-catalyzed carbonylative coupling of ethers with amines to construct α-carbonylated ethers has been achieved. Remarkably, Alfuzosin, a medicine for treatment of benign prostatic hyperplasia (BPH), can be synthesized by this process straightforwardly. Notably, this protocol presents the first example on the direct carbonylative reaction of ethers.

Cobalt‐Catalyzed Direct Aminocarbonylation of Ethers: Efficient Access to α‐Amide Substituted Ether Derivatives

AbstractEthers are of central importance in the fields of biomass, energy, and organic chemistry. Herein, a novel cobalt‐catalyzed carbonylative coupling of ethers with amines to construct α‐carbonylated ethers has been achieved. Remarkably, Alfuzosin, a medicine for treatment of benign prostatic hyperplasia (BPH), can be synthesized by this process straightforwardly. Notably, this protocol presents the first example on the direct carbonylative reaction of ethers.

Theoretical Approach Using DFT Calculations of Novel Oxime Derivatives

This study used the density functional theory (DFT) methods to evaluate the geometrical properties, UV, the lowest unoccupied molecular orbital (LUMO), the highest occupied molecular orbital (HOMO) analysis, and the molecular electrostatic potential (MEP) of oxime ether derivatives containing a quinoxaline. In addition, the stability of the molecule resulting from hyper conjugative interactions charge delocalization was studied using a natural bond orbital (NBO) analysis. The HOMO-LUMO energy gaps indicated different charge-transfer possibilities within the regarded molecules. Eventually, NBO analysis demonstrates the charge transfer between the lone pairs and the localized bonds.

Pseudo-Crown ether II: Intracellular and solution-, SiNPs based test-kits for ppm level detection of H2S gas

Perylene diimide based pseudo-Crown ether derivatives have been synthesized and characterized and their photophysical properties towards Fe3+ and H2S in 50% HEPES buffer–CH3CN and CH3CN solutions have been studied. PDI 1 showed formation of supramolecular aggregates with nanorods (dimer) morphology. Upon addition of Fe3+ ions, nanorods of PDI 1 transformed to spheres and PDI 1/2 showed a decrease in absorbance at (542 nm) and emission (578 nm) intensities supported by Job's plot, DLS, CV, WXRD and NMR techniques. The detection limits for Fe3+ are as low as 0.6 μM. We utilized PDI 1+Fe3+ complex as an ensemble for detection and discrimination of bio thiol derivatives. Upon addition of H2S (7.5 μM) and Cys (19 μM), the ensemble showed an increase at 542/578 nm (‘OFF-ON’) and further addition of H2S/Cys caused a decrease at same wavelength (‘ON-OFF’) with formation of new absorbance band at 630 nm (‘OFF-ON’). The mechanism of interaction of H2S involves reduction of Fe3+ to Fe2+ ions, followed by binding of HS− to form (PDI 1+Fe2++HS) complex. PDI 1 and PDI 1+Fe3+ complex has been successfully utilized for bioimaging of Fe3+ ions and H2S, respectively in live MG-63 cells. The solution and silica NPs based colorimetric test-kits were fabricated and detection of 30–60 ppm H2S gas has been achieved. These ‘OFF-ON-OFF’ and ‘ON-OFF-ON’ molecular switches mimic functioning of IMPLICATION, AND logic gates.

Design and Synthesis of Novel Oleanolic Acid-Linked Disulfide, Thioether, or Selenium Ether Moieties as Potent Cytotoxic Agents.

A series of novel oleanolic acid (OA)-linked disulfide, thioether, or selenium ether derivatives was synthesized, and their antiproliferative activity was evaluated against human liver cancer (BEL-7402 and HepG-2), colon cancer (HCT116), and normal liver (L02) cell lines using methyl thiazolyl tetrazolium assay (MTT). Preliminary bioassay results revealed that OA derivatives modified at the C3-OH position, i. e., compound a4 containing sulfide ether, exhibited the best antiproliferative activity against BEL-7402 cells, with an IC50 value of 5.70±0.82 μM. Further flow cytometry assays revealed that compound a4 exerted its antiproliferative effects by inducing cell cycle arrest in the G2/M phase leading to apoptosis. Moreover, compared with the lead compound OA and the positive control drug 5-fluorouracil (5-FU), the OA derivatives demonstrated potent antiproliferative activities against the cancer cell lines.