Esterification Of Maleic Acid Research Articles

Unlocking the potential of dimethyl fumarate: enhancing oncolytic HSV-1 efficacy for wider cancer applications.

Immunotherapy and specifically oncolytic virotherapy has emerged as a promising option for cancer patients, with oncolytic herpes simplex virus-1 (oHSV-1) expressing granulocyte macrophage colony stimulating factor being the first OV to be approved by the FDA for treatment of melanoma. However, not all cancers are sensitive and responsive to oncolytic viruses (OVs). Our group has demonstrated that fumaric and maleic acid esters (FMAEs) are very effective in sensitizing cancer cells to OV infection. Of note, these FMAEs include dimethyl fumarate (DMF, also known as Tecfidera®), an approved treatment for multiple sclerosis and psoriasis. This study aimed to assess the efficacy of DMF in combination with oncolytic HSV-1 in preclinical cancer models. We demonstrate herewith that pre-treatment with DMF or other FMAEs leads to a significant increase in viral growth of oHSV-1 in several cancer cell lines, including melanoma, while decreasing cell viability. Additionally, DMF was able to enhance ex vivo oHSV-1 infection of mouse-derived tumor cores as well as human patient tumor samples but not normal tissue. We further reveal that the increased viral spread and oncolysis of the combination therapy occurs via inhibition of type I IFN production and response. Finally, we demonstrate that DMF in combination with oHSV-1 can improve therapeutic outcomes in aggressive syngeneic murine cancer models. In sum, this study demonstrates the synergistic potential of two approved therapies for clinical evaluation in cancer patients.

Enhanced Modification of Fast-Growing Wood: Application and Evaluation of Castor Oil-Based Unsaturated Polyester Resin.

A type of multifunctional maleic acid ester monomer (COEGMA) was synthesized using castor oil as raw material, and green wood-plastic composites were prepared by chemically impregnating and curing the monomer into wood. The structure of the synthesized products at various stages was determined by FT-IR spectroscopy, 1H NMR, and GPC, and the curing experimental conditions were optimized. The results show that the water absorption of wood-plastic composites treated with COEGMA is reduced from the original 167.3% to less than 20%. The compressive strength has increased from 35.7 to 86.1 MPa, and the thermal stability has also increased by 40 °C. This research provides promising prospects for the development of environmentally friendly wood-plastic composites, especially as fossil resources become scarce and environmental pollution becomes more severe.

Mechanical and thermal properties of poly(lactic acid) plasticized with dibutyl maleate and fumarate isomers: Promising alternatives as biodegradable plasticizers

The use of plasticizers, polymer blends and composites have been reported as effective strategies to overcome the rigidity and brittleness of PLA, drawbacks that commonly limits its application. In this study poly(lactic acid) was plasticized with 7 and 12 wt% of dibutyl esters of maleic or fumaric acid. The choice of plasticizer was motivated by recent studies reporting the biodegradability of maleic and fumaric esters and their efficiency as green plasticizers. This current study evaluates how the chemical structure, specifically the cis–trans isomerism of the plasticizer, can affect the plasticizing properties on PLA. The thermal and mechanical properties of the plasticized specimens were evaluated by DSC, DMA, Stress-Strain and Relaxation tests. The results indicated that samples plasticized with dibutyl fumarate exhibited a lower glass transition temperature (Tg), lower Young’s modulus, and higher elongation at break than specimens plasticized with dibutyl maleate.

Kinetics of ultrasound‐assisted esterification of maleic acid and butanol using heterogeneous catalyst

AbstractThe present research investigates the kinetics of ultrasound‐assisted synthesis of dibutyl maleate using a heterogeneous catalyst (Amberlyst‐15) in solvent‐free system. Reaction parameters were optimized based on conversion by varying the various parameters such as n‐butanol to maleic acid mole ratio, temperature, molecular sieves, catalyst loading, power, and duty cycle. Optimization of parameters resulted in 56.2% yield at 343 K, alcohol to acid mole ratio as 4:1, catalyst loading of 4%, molecular sieves of 4% with an ultrasound power input of 100 W with 60% duty cycle and 22 kHz frequency. In the presence of ultrasound, the reaction time reduced to 120 min in comparison with 240 min of the conventional process. The experimental kinetic data were correlated using Pseudo‐Homogeneous model as well as heterogeneous models like Eley‐Rideal model and Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) model based on single as well as dual‐site mechanisms. LHHW (reactants and products) model was found to be the best fit. The results proved that the reaction follows second‐order kinetics. The activation energy of the reaction was calculated as 14.64 kJ/mol.

Development of biobased waterborne coatings containing Ecomer®: An alkyl polyglucoside maleic acid ester monomer

Partially biodegradable waterborne coatings with bio-contents ranging from 30 % to 65% have been developed using Ecomer®, an alkyl polyglucoside maleic acid ester functional comonomer, by seeded semibatch emulsion polymerization. The composition of the commercial monomer was characterized and its copolymerization was carried out analyzing its incorporation degree. Thereafter, waterborne coating systems containing 2-Octyl acrylate and isobornyl methacrylate as main comonomers were developed and fully analyzed. The caramelization process allowed to incorporate the free Ecomer® content as well as to improve both mechanical and coating properties. IR, TGA and DMTA analysis shed light about this process and its correlation with the final properties. The incorporation of sugar moieties resulted in partial biodegradability of the coatings films, being less biodegradable the caramelized ones.

Role of moisture in esterification of wood and stability study of ultrathin lignocellulose nanofibers

Esterification of wood with maleic anhydride assists its mechanical fibrillation to realize ultrathin lignocellulose nanofibers (LCNFs) with thicknesses of 3 nm. We investigated the effects of the moisture content of raw wood and the esterification reaction time on the properties of the LCNFs. Increasing the moisture content of raw wood decreases both the amount of maleic acid ester and the lignin content in esterified wood. Moisture is required not only for a high degree of esterification but also for the removal of lignin to prepare ultrathin LCNFs suitable for mechanical fibrillation. 2D HSQC-NMR analysis reveals that cellulose, hemicellulose, and lignin are esterified. The maleic acid ester introduced on the LCNF surface tends to be hydrolyzed, resulting in the detachment of the maleic acid ester. Ester hydrolysis, which is facilitated under alkaline and high temperature conditions, converts the LCNF suspension into a gel. Finally, the stability against ultra violet (UV) light irradiation is examined. Since lignin absorbs UV light, the reduction in the viscosity of the LCNF suspension is lower than that of the pure cellulose nanofiber suspension. These results should contribute to the effective utilization of wood, which is the most abundant biomass.

Eco-friendly synthesis of maleate ester: A comparison between solid acid and enzyme-catalyzed esterification

In this study, two different eco-friendly methods were investigated for the synthesis of a dicarboxylic acid ester, dimethyl maleate (DMM). One method involves application of molybdate sulfuric acid (MSA) as a solid acid catalyst in the esterification of maleic acid with methanol. The effects of three parameters namely, temperature, time, and catalyst amount on the product synthesis were determined. By using response surface methodology (RSM) based on central composite rotatable design (CCRD), maximum conversion of the maleic acid (87.6%) was obtained at reaction conditions of 120 °C, 0.27 g MSA, and 103 min. In the other method, DMM was synthesized by enzymatic esterification using immobilized Candida antarctica lipase B as the catalyst. Maximum conversion was 72.3%, at the optimal conditions of 62.5 °C, 0.27 g enzyme, and 249 min. The reusability study showed that MSA lost its catalytic activity after five cycles. However, the immobilized enzyme maintained its activity and stability. The results indicated that both employed methods were efficient for the synthesis of DMM. A higher conversion could be obtained using MSA as the catalyst, which could be compensated by better reusability of the enzyme. The enzyme-catalyzed reaction was more energy efficient but it took a longer time to obtain maximum reaction yield.

Dimethyl fumarate potentiates oncolytic virotherapy through NF-κB inhibition.

Resistance to oncolytic virotherapy is frequently associated with failure of tumor cells to get infected by the virus. Dimethyl fumarate (DMF), a common treatment for psoriasis and multiple sclerosis, also has anticancer properties. We show that DMF and various fumaric and maleic acid esters (FMAEs) enhance viral infection of cancer cell lines as well as human tumor biopsies with several oncolytic viruses (OVs), improving therapeutic outcomes in resistant syngeneic and xenograft tumor models. This results in durable responses, even in models otherwise refractory to OV and drug monotherapies. The ability of DMF to enhance viral spread results from its ability to inhibit type I interferon (IFN) production and response, which is associated with its blockade of nuclear translocation of the transcription factor nuclear factor κB (NF-κB). This study demonstrates that unconventional application of U.S. Food and Drug Administration-approved drugs and biological agents can result in improved anticancer therapeutic outcomes.

Сравнительный кинетический анализ термической деструкции гидрогеля на основе полиметилвинилового эфира малеиновой кислоты сшитого полипропиленгликолем

Kinetic analysis was made applying TG/DTG/HF data in nitrogen and air atmospherefor thermal decomposition of hydrogel of polymethylvinyl maleic acid ester, linked with polypropylene glycol, at different heating rates. TG/DTG/HF data were processed according to the followingkinetic models: Friedman, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, Coates-Redfern and nonparametric kinetic method (NPK) was used, to obtain the following kinetic parameters: activationenergy and pre-exponential factor.According to the attained values of activation energy, the mechanism of degradation of the hydrogel was suggested. Values of kinetic parameters attained by different methods, are compliant to eachother. Isoconversion method is one of the methods for definition of activation energy; this methoddoes not require knowledge on analytical form of conversion function, and gives the possibility todefine the activation energy against conversion degree as well.To obtain full kinetic analysis it is necessary to process the data using non-parametric kineticmethod. Non-parametric kinetics method (NPK) of Serra, Nomen and Sempere is based upon thesuggestion that reaction velocity may be expressed as multiplication of two independent functions,f (α) and k (T). Reaction model f (α) considers the dependence of conversion degree, and k (T)considers the temperature dependence.

Esterification of maleic acid and butanol using cationic exchange resin as catalyst

Dibutyl maleate is a perfumery ester used as an intermediate in the production of paints, adhesives, and copolymers. Esterification of maleic acid and butanol was studied in presence of acidic cation exchange resin as a catalyst. The objective of this work was to test the suitability and efficacy of heterogeneous catalysts such as Indion 225H and Amberlyst-15 in the synthesis of dibutyl maleate. Various parameters deciding the conversion of reaction such as mole ratio, catalyst loading, molecular sieves, speed of agitation and effect of temperature were optimized for the maximum rate and conversion. The activation energy was calculated as 71.5 kcal/mol. Diffusivity value $$\hbox {D}_{\mathrm{AB}}$$ (maleic acid in n-butanol) at $$80\,^{\circ }\hbox {C}$$ was calculated as $$5.08\times 10^{-10}~\hbox {m}^{2}/\hbox {s}$$ and effective diffusivity ( $$\hbox {D}_{{\text {e-A}}})$$ was calculated as $$5.08\times 10^{-11}\,\hbox {m}^{2}/\hbox {s}$$ . Solid–liquid mass transfer coefficient ( $$\hbox {k}_{{\text {sl-A}}}$$ ) was calculated as $$6.77\times 10^{-6}\,\hbox {m/s}$$ for the particle size of Amberlyst-15 as 0.5 mm. Synopsis. Synthesis of dibutyl maleate was carried out using ion exchange resin as a catalyst. Effect of various parameters on the conversion of reaction like mole ratio, catalyst loading, molecular sieves, the speed of agitation and effect of temperature was studied.

USE OF SURFACE MODIFIED BENTONITE CLAY CATALYST FOR ESTERIFICATION OF MALEIC ACID WITH ETHANOL

Inorganic clays are being exploited as solid catalysts support for vide verity of organic reactions. Surface modified (SM) clay was synthesized by sulfuric acid treatment of raw bentonite clay. Acid treated clay was characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The esterification of maleic acid with ethanol using SM clay catalyst was carried out to study an effect of various parameters viz. speed of agitation, catalyst loading, mole ratio of reactants and temperature. SM bentonite shows better catalytic activity towards maleic acid-ethanol esterification. A Pseudo-homogeneous kinetic model was used to validate the experimental data. Kinetic parameter such as rate constant and activation energy was estimated for the reaction.

Synthesis of a glucose-based surfmer and its copolymerization with n-butyl acrylate for emulsion pressure sensitive adhesives

A glucose-based vinyl surfmer, i.e. butyl polyglucoside maleic acid ester (BGMAH), was synthesized and characterized. Macroemulsion copolymerization of BGMAH with n-butyl acrylate (n-BA) was investigated. The structure of the synthesized BGMAH was confirmed using Fourier transform infrared spectroscopy and a series of 2-D homo- and heteronuclear NMR spectra. Its surfactant properties were confirmed by determination of the critical micelle concentration. The semi-batch emulsion copolymerization was monitored in situ using FTIR spectroscopy. The particle size and its distribution of the emulsions and the gel phase of the polymers were determined. The glass transition temperatures were assessed using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The obtained emulsions were tested for potential application in pressure sensitive adhesives by measuring the adhesion properties of copolymer films (peel strength, tack and shear resistance). It was found that synthetic acrylates could be replaced by the modified glucose in the emulsion polymerization recipe. The adhesion properties were improved when 25wt% of BGMAH was added in reaction mixture.

Comparative studies of thiol-sensitive fluorogenic probes for HAT assays

Histone acetyltransferases (HATs) catalyze the acetylation of specific lysine residues in histone and nonhistone proteins. Recent studies showed that acetylation is widely distributed among cellular proteins, suggestive of diverse functions of HATs in cellular pathways. Nevertheless, currently available assays for HAT activity study are still quite limited. Here, we evaluated a series of thiol-sensitive fluorogenic compounds for the detection of the enzymatic activities of different HAT proteins. Upon conjugation to the thiol group of HSCoA, these molecules gain enhanced quantum yields and strong fluorescence, permitting facile quantitation of HAT activities. We investigated and compared the assay performances of these fluorogenic compounds for their capability as HAT activity reporters, including kinetics of reaction with HSCoA, influence on HAT activity, and fluorescence amplification factors. Our data suggest that CPM and coumarin maleic acid ester are excellent HAT probes owing to their fast reaction kinetics and dramatic fluorescence enhancement during the HAT reaction. Further, the microtiter plate measurements show that this fluorescent approach is robust and well suited for adaption to high-throughput screening of small molecule inhibitors of HATs, highlighting the value of this assay strategy in new drug discovery.

Detection of Long Alkyl Esters of Succinic and Maleic Acid Using TLC-MALDI-MS

Four esters of succinic and maleic acid were synthesized, separated by thin-layer chromatography (TLC), and identified using matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). A comparison of matrix materials showed that 2,6-dihydroxybenzoic acid (2,6-DHB) yielded a greater ionization efficiency than 2,5-DHB prior to TLC separation. The location of each ester sample on the TLC plate was estimated by comparing the developed plate with a duplicate plate that had been visualized by immersion in a <TEX>$KMnO_4$</TEX> solution. Generally, mass spectra obtained from the <TEX>$KMnO_4$</TEX>-visualized plate were relatively poor. Reproducible mass spectra with high peak abundance were difficult to obtain using the 2,6-DHB matrix from crude synthetic esters extracted from the TLC plates. Significant improvements in both reproducibility and sensitivity were realized by using pencil lead as the MALDI matrix. The current methodology will be beneficial to organic chemists since it can provide a guideline for simple and rapid characterization of small organic compounds.

Waterborne polyesters partially based on renewable resources

AbstractA new experimental approach for preparing biobased, water‐soluble polyesters (PEs) via titanium(IV) n‐butoxide‐catalyzed bulk polycondensation is presented. In the described method polymers were obtained from isosorbide, maleic anhydride and poly(ethylene glycol) (PEG). The chemical structure of the synthesized PEs was confirmed using 2D NMR spectroscopy and by titration methods. Careful analysis of 2D NMR spectra viz. correlation spectra (COSY), heteronuclear single quantum correlation spectra (HSQC) and heteronuclear multiple‐bond correlation spectra (HMBC) allowed to accomplish the complete proton assignment of isosorbide, PEG, and unsaturated acid residues in the PEs. Moreover, by using NMR spectroscopy the transformation of maleic anhydride into fumaric acid ester and the absence of maleic acid ester units in the final polymer were proven. However, during polycondensation part of the unsaturated bonds has reacted in a Michael addition with isosorbide or PEG. Gel permeation chromatography measurements revealed that the unsaturated PEs have Mn values in the range 3000–5000 g/mol. These PEs, with a low content of carboxylic acid end groups, exhibited sufficient thermal resistance for practical applications, for example, as free radical curable coatings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Micelle dyeing with low liquor ratio for reactive dyes using dialkyl maleic acid ester surfactants

Micelle dyeing with low liquor ratio is novel fabric dyeing method for cleaner production. Preparation and interaction of dye-surfactant micelles using dibutyl maleic acid ester sodium sulfate surfactant were investigated by UV–Vis spectra. Dyeing properties of cellulose fabrics using micelle dyeing with low liquor ratio were discussed by color yields ( K/ S), color differences (Δ E), exhaustion ( E), fixation ( F) and reactivity ( R) of three reactive dyes. The results show that reactive dye molecules could be solved in surfactant micelles and form stable dye-surfactant micelles. Micelles formed by dibutyl maleic acid ester sodium sulfate had good anti-agglomeration effect on dye solutions. Liquor ratio of micelle dyeing for cellulose fabrics could be reduced from 1:15 to 1:5. Leveling properties of three reactive dyes using micelle dyeing were good. The exhaustion, fixation and reactivity of all three dyes using micelle dyeing were similar with the conventional dyeing technology. Wet rubbing, washing and perspiration fastnesses of dyed samples using micelle dyeing were also good. Micelle dyeing with low liquor ratio can save a large amount of water and energy.

N-Glycosylhydroxylamines as Masked Polyhydroxylated Chiral Nitrones in Cycloaddition Reactions: An Access to Pyrrolizidines

- N-glycosylhydroxylamines undergo 1,3-dipolar cycloadditions via their tautomeric open chain nitrones. Cycloadditions to maleic acid esters occur with high diastereoselectivity and the products can be converted into highly functionalized pyrrolizidines.

Synthesis and characterization of biodegradable polymer: Poly (ethene maleic acid ester- co- d, l-lactide acid)

A novel biodegradable polymer—poly (ethene maleic acid ester- co- d, l-lactide acid) was synthesized by copolymerizing lactide and prepolymer, which was prepared by the condensation of maleic anhydride and glycol, using p-toluene sulphonic acid as a catalyst, attempting to improve the hydrophilicity, increase flexibility and modulate the degradation rate. FTIR, 1H NMR, MALLS and DSC were employed to characterize these polymers.

Synthesis, structure, and thermolysis of (fullerene)(toluene)dicarbonylchromium

Fullerene C 60 has 30 essentially localized double bonds and can form η 2 complexes with transition metals. Molybdenum and tungsten π complexes of dihaptocoordinated fullerene with different ligands, such as CO, phenanthroline, α , α -dipyridyl, triphenylphosphine, and maleic and fumaric acid esters, have been prepared and structurally characterized [1–4]. The η 2 -C 60 complex with the (diphosphine)tricarbonylchromium moiety has been characterized by spectral methods [5]. As is known, (arene)tricarbonylchromium complexes can exchange the CO group for alkenes when exposed to UV irradiation [6]. Therefore, we studied the interaction of C 60 with (toluene)tricarbonylchromium under UV irradiation.

Model Studies Towards Alternative Cross-Linking of Unsaturated Polyesters

Abstract: Fumaric and maleic acid esters are functionalised with propargylamine. A subsequent Pd/Cu-catalysed oxidative homo-coupling of two alkyne moieties yields the corresponding dimers. Hence, a model ofan unsaturated polyester chain is cross-linked in a well-defined, metal-mediated reaction in a very high yield. Keywords : Unsaturated polyester, cross-linking, catalytic, alkyne coupling. INTRODUCTION Unsaturated polyester resins are heterochain polymers,containing repeating ester groups and aliphatic double bondsin the backbone [1]. These chains are generally co-polymerised in a free-radical chain-growth process, with avinyl monomer, usually styrene, to yield the final product, athree-dimensional cross-linked network [1, 2]. Sinceenvironmental legislation becomes more and more stringentconstantly reducing the amount of monomeric components,which can be used in unsaturated polyester products, thedevelopment of alternative cross-linking methods, reducingor completely avoiding possible emissions of harmful,volatile compounds, e.g. of styrene, is of particular interest.Radical cross-linking processes do not yield very welldefined products, instead they give rise to different chainlengths of the linkages, irregular, incomplete consumptionof the double bonds of the polyester heterochain and directlinking of the latter. In addition, side-reactions such ashomopolymerisation of styrene occur [3]. So, we opted for awell-defined metal-mediated reaction that could circumventthese problems. Further considering an unsaturation in thelinkage a desirable feature, since it provides the possibilityfor additional cross-linking if demanded to alter theproperties of the final product, the metal-catalysed couplingof alkynes is highly attractive for its wide scope [4]. Here wereport a model reaction for an alternative cross-linking ofunsaturated polyesters