Vinyl Ether Derivatives Research Articles

Synthesis, biological and computational evaluation of novel cyanomethyl vinyl ether derivatives.

This work explores the biological evaluation of novel cyanomethyl vinyl ether derivatives as antiproliferative agents. Tubulin, crucial to microtubule structure and function, is a target for cancer therapies. In vitro cytotoxicity assessments revealed significant activity in SKOV3 ovarian carcinoma cells and A549 lung carcinoma cells. Structure-Activity Relationship (SAR) analysis indicated that the E isomer and specific substitutions influenced the biological activity. Computational assays predicted favorable ADME properties, highlighting potential as anticancerous agents. Molecular docking studies demonstrated that compound 12E, with the E geometry of the double bond and fused polyaromatic rings such as phenanthrene, has robust interaction with tubulin, suggesting enhanced stability due to diverse amino acid interactions. Comparative spatial distributions with colchicine further indicated potential mechanistic similarities.

Synthesis of degradable polymers via 1,5-shift radical isomerization polymerization of vinyl ether derivatives with a cleavable bond

AbstractWe report a novel method for synthesizing degradable polymers based on 1,5-shift radical isomerization polymerizations of vinyl ethers with transferable atoms or groups and in-between acid-cleavable ether linkages in the side chains. In particular, vinyl ethers with side chains composed of thiocyano and p-methoxybenzyl ether groups underwent radical isomerization polymerizations via 1,5-shifts, in which a vinyl ether radical abstracted the cyano group intramolecularly to generate a thiyl radical and result in a polymer with a p-methoxybenzyl ether linkage in the main chain. The obtained polymer was easily degraded into low molecular-weight products with HCl solution. Furthermore, the copolymerization with vinyl acetate proceeded via 1,5-shift isomerization to introduce cleavable linkages in the main chains of the copolymers, which were similarly degraded.

Development of stealth nanoparticles coated with poly(2‐methoxyethyl vinyl ether) as an alternative to poly(ethylene glycol)

AbstractPoly(ethylene glycol) (PEG) modification, also known as PEGylation, has been extensively used to improve the stability of nanoparticles for nanomedical applications. However, PEG exhibits antigenicity in some formulations, motivating researchers to explore alternative polymers. Herein, poly(vinyl ether) (PVE) derivatives are highlighted as promising alternatives to PEG because they form intermediate water molecules that suppress non‐specific protein adsorption and platelet adhesion to the material surface. We prepared a water‐soluble PVE derivative, poly(2‐methoxyethyl vinyl ether) (PMOVE), and utilized it as a surface modifier for gold nanoparticles (AuNPs) as model nanoparticles. PMOVE with a thiol terminus was synthesized and confirmed to form an intermediate water molecule using differential scanning calorimetry. Similar to the synthesis of PEGylated AuNPs (PEG‐AuNPs), PMOVE‐modified AuNPs (PMOVE‐AuNPs) were successfully fabricated with an appreciably high density of PMOVE palisades via a thiol‐gold coordination reaction. Similar to PEG‐AuNPs, PMOVE‐AuNPs showed reduced serum protein adsorption and prolonged blood circulation. Additionally, no significant cytotoxicity was observed after incubation of a murine macrophage cell line, RAW264.7, with PMOVE‐AuNPs. Our results indicate that the PMOVE modification increases the stealthiness of nanoparticles that is equivalent to that achieved by PEGylation.

In vitro activity and mechanism of cell death induction of cyanomethyl vinyl ethers derivatives against Trypanosoma cruzi

Chagas disease causes a problematic pathology that can lead to megacolon and heart disease, and can even cause the death of the patient. Current therapies for this disease are the same as they were 50 years ago, are not fully effective and have strong side effects. The lack of a safe and effective therapy makes it necessary to search for new, less toxic and totally effective compounds against this parasite. In this work, the antichagasic activity of 46 novel cyanomethyl vinyl ether derivatives was studied. In addition, to elucidate the type of cell death that these compounds produce in parasites, several events related to programmed cell death were studied. The results highlight four more selective compounds, E63, E64, E74 and E83, which also appear to trigger programmed cell death, and are therefore postulated as good candidates to use in future therapeutics for Chagas disease.

Increasing the Hydrophilicity of Cyclic Ketene Acetals Improves the Hydrolytic Degradation of Vinyl Copolymers and the Interaction of Glycopolymer Nanoparticles with Lectins.

Radical ring-opening polymerization (rROP) of cyclic ketene acetals (CKAs) with traditional vinyl monomers allows the synthesis of degradable vinyl copolymers. However, since the most commonly used CKAs are hydrophobic, most degradable vinyl copolymers reported so far degrade very slowly by hydrolysis under physiological conditions (phosphate-buffered saline, pH 7.4, 37 °C), which can be detrimental for biomedical applications. Herein, to design advanced vinyl copolymers by rROP with high CKA content and enhanced degradation profiles, we reported the copolymerization of 2-methylene-1,3,6-trioxocane (MTC) as a CKA with vinyl ether (VE) or maleimide (MI) derivatives. By performing a point-by-point comparison between the MTC/VE and MTC/MI copolymerization systems, and their counterparts based on 2-methylene-1,3-dioxepane (MDO) and 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), we showed negligible impact on the macromolecular characteristics and similar reactivity ratios, suggesting successful substitution of MDO and BMDO by MTC. Interestingly, owing to the hydrophilicity of MTC, the obtained copolymers exhibited a faster hydrolytic degradation under both accelerated and physiological conditions. We then prepared MTC-based glycopolymers, which were formulated into surfactant-free nanoparticles, exhibiting excellent colloidal stability up to 4 months and complete degradation under enzymatic conditions. Importantly, MTC-based glyconanoparticles also showed a similar cytocompatibility toward two healthy cell lines and a much stronger lectin affinity than MDO-based glyconanoparticles.

A facile synthesis of ferrocene functionalized vinyl ethers and their application as optical sensors for Cu2+ ions detection

In this note, facile synthesis of ferrocenyl vinyl ethers has been reported through a NaOHassisted CO bond-forming reaction of various primary alcohol and ferrocene chlorovinyl derivatives. The presented method is high yielding and delivers the products substantially in a quite instant time. Functionalised ferrocenyl chlorovinyl derivatives (CHO, CN and C(CN)2) were found to be well tolerated for a wide range of primary alcohols. All the ferrocenated vinyl ethers are novel and not reported earlier. The vinyl ether derivatives formed through the reactions of 1,2- and 1,3-diols were tested for the optical metal sensing capabilities, and selectivity was observed for Cu2+ ions. The ferrocenated malenonitrile contaning vinyl ether showed a high sensitivity and selectivity towards Cu2+ among all the other tested metal ions. Upon interaction with Cu2+, the yellow color of this vinyl ether change into colourless and make the naked eye detection of Cu2+ ion under mild condition and very low concentrations. The receptor (vinyl ether) was created with a detection limit of 8.18 µM, for the highly selective, specific, and sensitive detection of Cu2+. To improve the applicability of this sensing system for onsite quantitation, TLC silica strips soaked in the compound solution was performed. Moreover, the application was further extended by incorporating mobile phone-based sensing studies.

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.

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

Unmasking the Hidden Carbonyl Group Using Gold(I) Catalysts and Alcohol Dehydrogenases: Design of a Thermodynamically-Driven Cascade toward Optically Active Halohydrins

A concurrent cascade combining the use of a gold(I) N-heterocyclic carbene (NHC) and an alcohol dehydrogenase (ADH) is disclosed for the synthesis of highly valuable enantiopure halohydrins in an aqueous medium and under mild reaction conditions. The methodology consists of the gold-catalyzed regioselective hydration of easily accessible haloalkynes, followed by the stereoselective bioreduction of the corresponding α-halomethyl ketone intermediates. Thus, a series of alkyl- and aryl-substituted haloalkynes have been selectively converted into chloro- and bromohydrins, which were obtained in good to high yields (65–86%). Remarkably, the use of stereocomplementary commercial or made-in-house overexpressed alcohol dehydrogenases in Escherichia coli has allowed the synthesis of both halohydrin enantiomers with remarkable selectivities (98 → 99% ee). The outcome success of this method was due to the thermodynamically driven reduction of the ketone intermediates, as just a small excess of the hydrogen donor (2-propanol, 2-PrOH) was necessary. In the cases that larger quantities of 2-PrOH were applied, higher amounts of other by-products (e.g., a vinyl ether derivative) were detected. Finally, as an extension of this cascade transformation and exploration of the synthetic potential of chiral halohydrins, the synthesis of both enantiomers of styrene oxide has been developed in a one-pot sequential manner in very high yields (88–92%) and optical purities (97 → 99% ee).

Towards Dual-Metal Catalyzed Hydroalkoxylation of Alkynes

Poly (vinyl ethers) are compounds with great value in the coating industry due to exhibiting properties such as high viscosity, soft adhesiveness, resistance to saponification and solubility in water and organic solvents. However, the main challenge in this field is the synthesis of vinyl ether monomers that can be synthetized by methodologies such as vinyl transfer, reduction of vinyl phosphate ether, isomerization, hydrogenation of acetylenic ethers, elimination, addition of alcohols to alkyne species etc. Nevertheless, the most successful strategy to access to vinyl ether derivatives is the addition of alcohols to alkynes catalyzed by transition metals such as molybdenum, tungsten, ruthenium, palladium, platinum, gold, silver, iridium and rhodium, where gold-NHC catalysts have shown the best results in vinyl ether synthesis. Recently, the hydrophenoxylation reaction was found to proceed through a digold-assisted process where the species that determine the rate of the reaction are PhO-[Au(IPr)] and alkyne-[Au(IPr)]. Later, the improvement of the hydrophenoxylation reaction by using a mixed combination of Cu-NHC and Au-NHC catalysts was also reported. DFT studies confirmed a cost-effective method for the hydrophenoxylation reaction and located the rate-determining step, which turned out to be quite sensitive to the sterical hindrance due to the NHC ligands.

Synthesis of glucosamine vinyl ether derivative and its deuterated analog

The use of calcium carbide (in the presence of H2O) as a source of acetylene in the reaction with methyl 2-amino-4,6-O-benzylidene-2-deoxy-β-d-glucopyranoside under superbasic conditions (KF, KOH, DMSO, 130 °C, 3 h) led to the corresponding vinyl ether in 78% yield. The vinylation does not affect other reaction centers. Replacement of water with deuterium oxide in the reaction mixture gave a stable deuterated analog of this vinyl ether in 72% yield. The one-step isotopic enrichment was practically quantitative (isotopic purity >96%). Introduced deuterium atoms can be used as a convenient label in further transformations.

An exceptionally mild synthetic strategy using cascade reaction for 3,4‐dihydronaphthyridinones having aliphatic substituent on amide nitrogen

AbstractA facile synthetic procedure for 3,4‐dihydronaphthyridinone derivatives is described. This synthetic route involves the cascade reaction of methyl nicotinate having an ethoxyvinyl group with various amines. The desired cyclization products were obtained using pyridylacetaldehyde formation and subsequent reductive amination/cyclization with amines. For the preparation of vinyl ether derivatives, we employed the coupling reaction, and the method would be applicable to various related substrates. Furthermore, all the reactions to N‐alkyl products proceeded rapidly at ambient temperature in good yields using simple and safe protocols. This strategy allows the generation of dihydronaphthyridinone derivatives containing various amines.

Cationic copolymerization of isosorbide towards value-added poly(vinyl ethers)

Biomass-derived isosorbide (IS) was converted into a mono-glycal (i.e. vinyl ether) derivative (Gly-IS) to investigate its efficacy for cationic polymerization.

The 9H-Fluoren Vinyl Ether Derivative SAM461 Inhibits Bacterial Luciferase Activity and Protects Artemia franciscana From Luminescent Vibriosis.

Vibrio campbellii is a major pathogen in aquaculture. It is a causative agent of the so-called “luminescent vibriosis,” a life-threatening condition caused by bioluminescent Vibrio spp. that often involves mass mortality of farmed shrimps. The emergence of multidrug resistant Vibrio strains raises a concern and poses a challenge for the treatment of this infection in the coming years. Inhibition of bacterial cell-to-cell communication or quorum sensing (QS) has been proposed as an alternative to antibiotic therapies. Aiming to identify novel QS disruptors, the 9H-fluroen-9yl vinyl ether derivative SAM461 was found to thwart V. campbellii bioluminescence, a QS-regulated phenotype. Phenotypic and gene expression analyses revealed, however, that the mode of action of SAM461 was unrelated to QS inhibition. Further evaluation with purified Vibrio fischeri and NanoLuc luciferases revealed enzymatic inhibition at micromolar concentrations. In silico analysis by molecular docking suggested binding of SAM461 in the active site cavities of both luciferase enzymes. Subsequent in vivo testing of SAM461 with gnotobiotic Artemia franciscana nauplii demonstrated naupliar protection against V. campbellii infection at low micromolar concentrations. Taken together, these findings suggest that suppression of luciferase activity could constitute a novel paradigm in the development of alternative anti-infective chemotherapies against luminescent vibriosis, and pave the ground for the chemical synthesis and biological characterization of derivatives with promising antimicrobial prospects.

Pentannulation Reaction by Tandem Gold(I)-Catalyzed Propargyl Claisen Rearrangement/Nazarov Cyclization of Enynyl Vinyl Ethers.

The tandem gold(I)-catalyzed propargyl Claisen rearrangement/Nazarov cyclization of propargyl vinyl ether derivatives, followed by in situ reduction of the resulting carbonyl group, provides functionalized cyclopentadienes fused with various N-hetero- and carbacycles, including indoles, in good to excellent yields. The reaction occurs with high regioselectivity, with the position of the double bonds in the five-membered ring depending on the type of (hetero)cycle bearing the propargylic moiety and the side chain on the latter.

Facile transformation of 2H,3H-decafluoropentane (HFC-4310mee) into (Z)-2H-nonafluoropent-2-ene and its application to the synthesis of polyfluorinated homoallylic ketones by Claisen rearrangement

The dehydrofluorination of 2H,3H-decafluoropentane (HFC-4310mee) using 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) selectively gave (Z)-2H-nonafluoropent-2-ene as a bench-stable volatile liquid. Nucleophilic substitution reactions of (Z)-2H-nonafluoropent-2-ene with allylic alcohols gave the corresponding polyfluorinated allylic vinyl ether derivatives. The Claisen rearrangement of the polyfluorinated allylic vinyl ethers smoothly proceeded under ambient conditions to give polyfluorinated homoallylic ketones quantitatively. These results indicate the potential of 2H,3H-decafluoropentane as an inexpensive and easy-to-handle chemical feedstock for the syntheses of densely functionalized polyfluorinated organic compounds.

Diversifying Complexity by Domino Benzannulation of Polycyclic Natural Products.

Herein we describe a salicylaldehyde-annulation reaction as a plug and play toolkit to diversify the complexity of naturally occurring ketones. The protocol entails the transformation of the polycyclic natural ketone into its propargyl vinyl ether derivative (two synthetic steps) and its microwave-assisted imidazole-catalyzed domino rearrangement to generate the salicylaldehyde ring. This annexed unit allows further synthetic transformations: e.g., the installation of a pharmacophore module to generate natural product-pharmacophore hybrids endowed with unknown biological (pharmaceutical) annotations.

Lewis‐Base‐Catalyzed Alkylation Reaction of 4‐Hydroxycoumarins with Allenoates: Regioselective Synthesis of 2H‐[3,2‐c] Furocoumarins and 4‐Hydroxycoumarin Vinyl Ether Derivatives

AbstractA milder, more regioselective and practical approach to C3 or O‐alkylation reaction of 4‐hydroxycoumarins has been established. Both 2H‐[3,2‐c] furocoumarins and 4‐hydroxycoumarin vinyl ether derivatives could be efficiently prepared by alkylating 4‐hydroxycoumarins with electron‐deficient allenoates catalyzed by PPh3 and DBU, respectively. The reaction outcomes can be controlled by changing the catalysts, starting with the same reaction substrates. Possible reaction mechanisms have also been proposed

Accumulation of long-chain bases in yeast promotes their conversion to a long-chain base vinyl ether

Long-chain bases (LCBs) are the precursors to ceramide and sphingolipids in eukaryotic cells. They are formed by the action of serine palmitoyl-CoA transferase (SPT), a complex of integral membrane proteins located in the endoplasmic reticulum. SPT activity is negatively regulated by Orm proteins to prevent the toxic overaccumulation of LCBs. Here we show that overaccumulation of LCBs in yeast results in their conversion to a hitherto undescribed LCB derivative, an LCB vinyl ether. The LCB vinyl ether is predominantly formed from phytosphingosine (PHS) as revealed by conversion of odd chain length tracers C17-dihydrosphingosine and C17-PHS into the corresponding LCB vinyl ether derivative. PHS vinyl ether formation depends on ongoing acetyl-CoA synthesis, and its levels are elevated when the LCB degradative pathway is blocked by deletion of the major LCB kinase, LCB4, or the LCB phosphate lyase, DPL1. PHS vinyl ether formation thus appears to constitute a shunt for the LCB phosphate- and lyase-dependent degradation of LCBs. Consistent with a role of PHS vinyl ether formation in LCB detoxification, the lipid is efficiently exported from the cells.

Conjugation of Bioactive Molecules to a Fluorescent Dithiomaleimide by Photoin­duced and BEt3‐Initiated Thio‐Click Reactions

AbstractTwo versions of the free‐radical thiol–ene addition, a photoinduced reaction in the presence of 2,2‐dimethoxy‐2‐phenylacetophenone, and a UV‐light‐free hydrothiolation using triethylborane as the initiator, were studied for the conjugation of fluorescent dithiomaleimide to biologically active compounds. A dithiomaleimide derivative bearing a vinyl ether functionality was prepared as the alkene partner. This was coupled with a range of thiols, including thiosugars, captopril, N‐acetyl‐L‐cysteine, and sodium 2‐sulfonatoethanethiol. The Et3B‐initiated method was superior to the photoinduced reaction, as it minimized decomposition of the sensitive maleimide group. The vinyl ether derivative and the addition products showed green light emission in tetrahydrofuran. The compounds all showed almost identical absorption and emission spectra, proving that the structure of the thiols has no influence on the fluorescence properties of the maleimide part of the molecules. The hydrothiolation products showed relatively high quantum yields.