Tetramethyl Ester Research Articles

Exploitation of porphyrin-based titanium-rich porous organic polymers for targeted phosphopeptide enrichment from the serum of colorectal cancer individuals.

Aporphyrin-based titanium-rich porous organic polymer (Th-PPOPs@Ti4+) was designed based on immobilized metal ion affinity chromatography technique and successfully applied to phosphopeptide enrichment with 5,10,15,20-tetrakis(4-carboxyphenyl) porphine tetramethyl ester (TCPTE), 2,3-dihydroxyterephthalaldehyde (DHTA), and 2,3,4-trihydroxybenzaldehyde (THBA) as raw materials. Th-PPOPs@Ti4+ exhibited remarkable sensitivity (0.5 fmol),highselectivity (β-casein: BSA = 1:2000, molar ratio), outstanding recovery (95.0 ± 1.9%), reusability (10 times), and superior loading capacity (143mg·g-1). In addition, Th-PPOPs@Ti4+ exhibited excellent ability to specifically capture phosphopeptides from the serum of colorectal cancer (CRC) individuals and normal subjects. Sixty phosphopeptides assigned to 35 phosphoproteins were obtained from the serum of CRC individuals, and 43 phosphopeptides allocated to 28 phosphoproteins were extracted in the serum of healthy individuals via nano-LC-MS/MS. Gene ontology assays revealed that the detected phosphoproteins may be inextricably tied to CRC-associated events, including response to estrogen, inflammatory response, and heparin binding, suggesting that it is possible that these correlative pathways may be implicated in the pathogenesis of CRC.

Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications

The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redox flow batteries. Herein, three tetrathiofulvalene (TTF) derivatives with different substitution groups, namely TTF diethyl ester (TTFDE), TTF tetramethyl ester (TTFTM), and TTF tetraethyl ester (TTFTE), are prepared and their energy storage properties are evaluated. It has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester groups. The battery with a catholyte of 0.2 mol L−1 of TTFTE delivers a specific capacity of more than 10 Ah L−1 at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V vs. Li/Li+. Its capacity retention can be improved from 2.34 Ah L−1 to 3.60 Ah L−1 after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF species. The excellent cycling stability of the TIF esters is supported by their well-delocalized electrons, as revealed by the density function theory calculations. Therefore, the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active materials for non-aqueous redox flow batteries.

Ytterbium porphyrins complexes for NIR-luminescent diagnostics and magneto-luminescent theranostics of tumours

Promising ytterbium porphyrins complexes (YbPC) and nanocomposites on its base for NIR-luminescent diagnostics and magneto-luminescent cancer theranostics are presented. The considered complexes are very promising substances for the cancer luminescent diagnostics (LD) in the NIR spectrum region (800–1100 nm). For LD of malignant tumors of the skin and mucous membranes, a pharmaceutical composition of the «Fluroscan» type was developed. It has been established that YbPC can also be used as one of the main components of the nanocomposites created for cancer theranostics, including magneto-luminescent theranostics (MLT). For the purposes of MLT, a 3-component nanocomposite was developed, consisting of a polymer matrix (Lexan type), a diagnostic substance based on the ytterbium complex of hematoporphyrin IX tetramethyl ester, and a therapeutic FeOx component.

Chirogenesis and Pfeiffer Effect in Optically Inactive EuIII and TbIII Tris(β-diketonate) Upon Intermolecular Chirality Transfer From Poly- and Monosaccharide Alkyl Esters and α-Pinene: Emerging Circularly Polarized Luminescence (CPL) and Circular Dichroism (CD).

We report emerging circularly polarized luminescence (CPL) at 4f-4f transitions when lanthanide (EuIII and TbIII) tris(β-diketonate) embedded to cellulose triacetate (CTA), cellulose acetate butyrate (CABu), D-/L-glucose pentamethyl esters (D-/L-Glu), and D-/L-arabinose tetramethyl esters (D-/L-Ara) are in film states. Herein, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate (fod) and 2,2,6,6-tetramethyl-3,5-heptanedione (dpm) were chosen as the β-diketonates. The glum value of Eu(fod)3 in CABu are +0.0671 at 593 nm (5F1) and −0.0059 at 613 nm (5F2), respectively, while those in CTA are +0.0463 and −0.0040 at these transitions, respectively. The glum value of Tb(fod)3 in CABu are −0.0029 at 490 nm (5F6), +0.0078 at 540 nm (5F5), and −0.0018 at 552 nm (5F5), respectively, while those in CTA are −0.0053, +0.0037, and −0.0059 at these transitions, respectively. D-/L-Glu and D-/L-Ara induced weaker glum values at 4f-4f transitions of Eu(fod)3, Tb(fod)3, and Tb(dpm)3. For comparison, Tb(dpm)3 in α-pinene showed clear CPL characteristics, though Eu(dpm)3 did not. A surplus charge neutralization hypothesis was applied to the origin of attractive intermolecular interactions between the ligands and saccharides. This idea was supported from the concomitant opposite tendency in upfield 19F-NMR and downfield 1H-NMR chemical shifts of Eu(fod)3 and the opposite Mulliken charges between F-C bonds (fod) and H-C bonds (CTA and D-/L-Glu). An analysis of CPL excitation (CPLE) and CPL spectra suggests that (+)- and (–)-sign CPL signals of EuIII and TbIII at different 4f-4f transitions in the visible region are the same with the (+)-and (–)-sign exhibited by CPLE bands at high energy levels of EuIII and TbIII in the near-UV region.

Композитные наночастицы на основе лексанполимерной матрицы, иттербиевых комплексов порфиринов и оксида железа для БИК-люминесцентной диагностики и тераностики новообразований

Описаны методика синтеза и спектрально-люминесцентные свойства наночастиц, содержащих иттербиевый комплекс диметилового эфира протопорфирина IX в полимерной матрице на основе лексана, перспективных для использования в диагностике новообразований. Наночастицы обладают увеличенным временем жизни люминесценции в ближней инфракрасной области 700–1100 нм и практически полным отсутствием флуоресценции свободного основания порфирина в красной области спектра, что показывает перспективность использования полученных наночастиц для диагностических целей. Для целей тераностики проведен синтез многофункциональных наночастиц, содержащих ядро оксидов железа и лексан-полимерную оболочку, включающую в себя иттербиевый комплекс тетраметилового эфира гематопорфирина IX. Предполагается, что наночастицы оксидов железа ответственны за проведение процедуры локальной гипертермии.

Composite Nanoparticles Based on the Lexan Polymer Matrix, Ytterbium Complexes of Porphyrins, and Iron Oxide for NIR Luminescent Diagnostics and Neoplasm Theranostics

The synthesis procedure and the spectral luminescent properties of nanoparticles containing the ytterbium complex of protoporphyrin IX dimethyl ester in a Lexan-based polymer matrix, promising for application in neoplasm diagnostics, are described. Nanoparticles have an increased luminescence lifetime in the 700–1100 nm near infrared region and almost no porphyrin free base fluorescence in the red spectral region, which shows promise in using the nanoparticles for diagnostic purposes. For theranostic purposes, the synthesis of multifunctional nanoparticles with a core of iron oxides and a Lexan-polymer shell containing the ytterbium complex of hematoporphyrin IX tetramethyl ester was carried out. We assume iron oxide nanoparticles are responsible for the local hyperthermia procedure.

Photophysical properties and photodynamic therapy activity of ameso-tetra(4-carboxyphenyl)porphyrin tetramethyl ester–graphene quantum dot conjugate

Ameso-tetra(4-carboxyphenyl)porphyrin tetramethyl ester and the Zn and GaCl derivatives were π–π stacked with graphene quantum dots to form conjugates and their photophysical and photodynamic therapy properties were investigated.

Graphene oxide promoted synthesis of p-phenylenediamine antioxidants

Three p-phenylenediamine antioxidants (p-phenylenediamine-N,N,N′,N′-tetrapropionic acid tetramethyl ester, p-phenylenediamine-N,N,N′-tripropionic acid trimethyl ester, and p-phenylenediamine-N, N′-dipropionic acid dimethyl ester) were successfully synthesized via atom-economic aza-Michael addition of pphenylenediamine to methyl acrylate p-romoted by graphene oxide in water. The synthesized compounds were characterized by NMR, ESI-MS spectra, and elemental analyses. The effects of the solvent and graphene oxide on the reaction were investigated.

Efficient Esterification of Oxidized l-Glutathione and Other Small Peptides

Oxidized l-glutathione was esterified to the tetra methyl ester using thionyl chloride in methanol solvent. Other alcohols were tested and the reaction progress was monitored via ESI-MS. This procedure proved to be compatible with other small peptides not containing serine and cysteine residues. In contrast to previously reported methods this procedure provided convenient access to esterified peptides requiring no purification, extended reaction times, or complicated reaction setups.

The synthesis of bisphosphonate analogues of nucleotides – derivatives of (α-phenyl)(α-fluoro)methylenebisphosphonic acids

The synthetic methods of fluorine-containing mimetics of nucleozide-diphosphates based on the derivatives of (α-fluoro)(α-phenyl) methylenebisphosphonic acid containing the residues of 2-{1-[4-(toluene-4-sulfonyl)-5-per-fluoroalkyl-[1,2,3]triazol-2-yl]-ethoxy}-ethelene and {2,2-dimethyl-6-[4(toluene-4-sulfonyl)-5-pentafluoroethyl-[1,2,3] triazol-2-yl]-tetrahyro-furo[3,4-d][1,3]dioxol-4-yl}-methylene as ester groups have been developed. Selective mono-and bisdealkylation of methoxy-groups in the tetramethyl ester of (α-fluoro)(α-phenyl)methylenebisphosphonic acid allows to prepare in high yields the corresponding trimethyl or symmetrical dimethyl esters containing one or two free reactive phosphonic acids groups. These compounds are convenient starting materials for the synthesis of mixed esters of (α-fluoro)(α-phenyl)methylenebisphosphonic acid by esterefication of acidic functionalities using simple aliphatic alcohols (n-butanol) and such analogues of nucleosides as 2-{1-[4-(toluene-4-sulfonyl)-5-perfluoroalkyl-[1,2,3]triazol-2-yl]-ethoxy}-ethanols and {2,2-dimethyl-6-[4(toluene-4-sulfonyl)-5-pentafluoroethyl-[1,2,3]triazol-2-yl]-tetrahyro-furo[3,4-d][1,3]dioxol-4-yl}-methanol. The structure of the compounds obtained has been proven using the methods of IR, NMR (1H, 13C, 19F, 31P) spectroscopy, mass-spectra, and elemental analysis. The cytotoxicity and antiviral activity of the compounds synthesized have been studied on the model of the Epstein-Barr virus. The compound possessing a significant inhibitory effect on the Epstein-Barr virus reproduction has been found.

Synthesis of triple-bond-containing 1-hydroxy-1,1-bisphosphonic acid derivatives to be used as precursors in "click" chemistry: two examples.

The synthesis of novel (ω-alkynyl-1-hydroxy-1,1-diyl)bisphosphonic acid tetramethyl esters (1a-c), their P,P'-dimethyl esters (2a-c), and two trimethyl ester derivatives (3a and 3b) is reported. The prepared compounds can be attached to many kinds of molecules containing azide (-N3) functionalities using a "click" chemistry approach. As an example, bisphosphonate trimethyl ester 3a and P,P'-dimethyl ester 2b were attached to triethylene glycol to form triethylene glycol-bisphosphonate conjugates 4 and 5 as model compounds for further studies in, for example, nanoparticle targeting.

The Rational Synthesis of Fenidronate

The synthesis of the disodium salt of fenidronate by the reaction of benzoic acid with phosphorus trichloride and phosphorous acid in methanesulfonic acid was investigated and optimized. It was enough to use 3.2 equivalents of phosphorus trichloride and there was no need to apply phosphorous acid. Both the one-step and two-step versions led to similar results giving the product in ca. 45% yield and in high purity. It was also possible to start directly from benzoyl chloride or ethyl benzoate. The work-up included in all cases hydrolysis and pH adjustment followed by purification. The fenidronic acid standard that was necessary for the analysis of our samples was prepared by another approach, by the addition of dimethyl phosphite to the carbonyl group of the -oxophosphonate, followed by hydrolysis of the tetramethyl ester so formed. Keywords: Dronic acid, dronate, synthesis, intermediate, optimization, titration.

Thermolysis of trifluoromethyl-containing vinyldiazocarbonyl compounds and X-ray crystal structure analysis of unexpected reaction products

Two unusual compounds, 1,3a,6,6a-tetrahydro-3a,6a-bis(trifluoromethyl)-cyclopenta[c]pyrazol-3,4,5,6-tetracarboxylic acid tetramethyl ester (C16H14N2O8F6) (3) and 2-acetyl-5,7-bis(trifluoromethyl)-4-methyl-3-methoxy-2,4,6-cycloheptatrienecarboxylic acid methyl ester (C14H11F6O3) (4), were obtained from thermolysis of 3-trifluoromethyl-substituted vinyldiazocarbonyl compounds. The crystal structures of the products were determined as part of a larger comparison study on the thermal and Rh(II)-catalyzed reactions of F- and H-vinyldiazocarbonyl compounds. The resulting structures provide the first crystallographic characterization of bis(trifluoromethyl)substituted compounds of this kind. The pure compounds with all-carbon (4) and half-heterocyclic (3) skeletons are composed of a seven- and two-annulated five-membered rings in folded butterfly and envelope conformations, respectively.

Simple Route to Adducts of (Amino)(aryl)carbene with Phosphorus Pentafluoride

AbstractThe tetramethyl ester of (hydroxy)(phenyl)methylenebis(phosphonic acid) reacts with morpholinosulfur trifluoride (MOST) to provide, along with the expected product of the substitution of a hydroxy group by fluorine, the adduct of (morpholino)(phenyl)carbene with PF5, compound 3a. Fluorination of dimethyl α‐aroylphosphonates with MOST yields adducts of (amino)(aryl)carbene with PF5 (p‐XC6H4)(Morph)C:→PF5 [3a–f, where Morph is morpholyl, X = H (a), Me (b), OEt (c), F (d), Cl (e), CF3 (f)] as the major reaction products. The reaction mechanism proposed is based on experimental data and DFT calculations. The structure of adduct 3a was determined by X‐ray studies. Hydrolysis of compounds 3e and 3f, bearing substituents Cl and CF3 on the phenyl ring, respectively, yields previously unknown benzoylpentafluorophosphates [p‐XC6H4–C(=O)PF5]–MorphH+.

Mass spectrometry of polycyclic tetracarboxylic ('ARN') acids and tetramethyl esters

Polycyclic C(80) tetracarboxylic (so-called 'ARN') acids are found as calcium salts in deposits which form in certain oilfield pipelines and equipment. Characterisation of these acids is important for improving the prediction and hence avoidance or minimisation of oilfield deposition problems. Although several of the acids have been isolated and characterised (as regioisomeric mixtures) by nuclear magnetic resonance spectroscopy, mass spectrometric methods are likely to be much more useful for the routine analysis of oils and deposits containing the acids. A publication summarising the mass spectra of the purified acids and major derivatives might thus be a very useful source of reference for scientists and technologists studying these unusual compounds. We now report the characterisation of several of the purified acids and of the tetramethyl esters by electrospray ionisation mass spectrometry (ESI-MS) in both positive ion and negative ion modes, by multistage ESI-MS with a suggested rationalisation of the ions produced, by positive ion atmospheric solids analysis probe (ASAP) atmospheric pressure chemical ionisation (APCI), and by positive ion electron ionisation (EI)-MS. Tentative identifications of C(80) acyclic, mono-, bi- and tricylic tetraacids and the δ(13)C isotope values of a mixture of the semi-pure acids determined by MS are also reported for the first time.

HS-SPME GC/MS를 이용한 젤펜잉크의 휘발성 성분

젤펜잉크 중 휘발성 성분을 스크리닝하여 개체특성자료를 확보하고자 3개국에서 생산된 16종의 흑색 젤펜잉크 카트리지를 시료로 분석하였다. 검출된 성분은 총 20종으로 isopropylalcohol, 2-methyl-2-propanol, 2-butanone, hydrazinecarbothioamide, benzeneacetic acid (ethyl ester), benzeneacetic acid, dimethoxymethy-silane, 2,2-dimethoxybutane, tetrahydro-2-methyl-furan, 1,2-ethanediol, silicic acid (tetramethyl ester), 1,2-propanediol, propyleneglycol, 3-ethyl-3-hexanol, 1,1-dipropoxy-propane, 2-butoxy-ethanol, 2,2'-oxybisethanol, 1-butyl-benzene, 2-pyrrolidinone, 2-(2-butoxyethoxy)-ethanol이었다. 그중 2,2-dimethoxybutane은 3.02~47%의 비율범위로 16종 젤펜 모든 시료에서 검출되었으며 tetrahydro-2-methyl-furan의 경우 1.19~52.19%로 GP1을 제외한 15종의 시료에서 검출되었다. 특히 일본산 제품 5종에서는 1,2-ethanediol가 52.83~95.84%의 범위, 한국산 동아제품 3종에서는 76.17~93.51%의 범위로 1,2-propanediol가 높은 함유율로 나타나 생산국에 따른 특성과 제조사별 특정성분의 함유분포를 알 수 있어서 잉크 휘발성 성분으로 개체특성을 확인하였다. In this study, VOCs of black gel pen inks was screening to identify individual characteristic of gel pen inks. Detected VOCs was total 20 species(isopropylalcohol, 2-methyl-2-propanol, 2-butanone, hydrazinecarbothioamide, benzeneacetic acid (ethyl ester), benzeneacetic acid, dimethoxymethy-silane, 2,2-dimethoxybutane, tetrahydro-2-methyl-furan, 1,2-ethanediol, silicic acid (tetramethyl ester), 1,2-propanediol, propyleneglycol, 3-ethyl-3-hexanol, 1,1-dipropoxy-propane, 2-butoxy-ethanol, 2,2'-oxybisethanol, 1-butyl-benzene, 2-pyrrolidinone, 2-(2-butoxyethoxy)-ethanol). We detected 2,2-dimethoxybutane (3.02~47% ratio) and tetrahydro-2-methyl-furan (1.19~52.19% ratio), 1,2-ethanediol (52.83~95.84% ratio). In case of manufacturer, manufactured ink was able to discriminate between Japan and Korea by distinct characteristics (Japan: 1,2-ethanediol, 52.83~95.84%, Korea: 1,2-propanediol, 76.17~93.51%). The results of this study indicated that distinct characteristic about manufacturers and brands could make a classifring tool of inks for identification of between gel pen inks.

Luminescence properties of heterodinuclear Pt–Eu complexes from unusual nonadentate ligands

The synthesis of ligand L(1), based on the tetramethyl ester of [4'-ethynyl-(6,6''-bis(aminomethyl))-2,2':6',2''-terpyridine]tetrakisacetate, and its acidic form L(2), are described. Using a Cu-assisted coupling reaction, L(1) was connected to the Pt atom of a [(tpy)Pt] precursor (tpy = 2,2':6',2''-terpyridine) to afford the [(tpy)PtL(1)](BF(4)) metallosynthon, from which a hydrolysis reaction gave Na(3)[(tpy)PtL(2)]. The photophysical properties of the metallosynthons were studied by means of absorption and steady state emission spectroscopic techniques in various solvents, which revealed a dramatic impact of the solvent polarity. DFT and TDDFT calculations (B3LYP) were used to investigate the absorption and emission properties of the [(tpy)PtL(1)](+) system both in vacuo and in different solvents. Spectrophotometric titrations of [(tpy)PtL(1)](+) with EuCl(3) x 6 H(2)O in acetonitrile revealed the formation of complicated mixtures of complexes with different [(tpyPt(1))(x)Eu(y)] stoichiometries, all of which display the typical Eu(III) centred luminescence upon excitation into the Pt centred (1)MLCT absorption band. The energy transfer from the Pt subunit of [(tpy)PtL(2)](3-) to Eu(III) is inefficient in polar solvents, but it is restored in a TFA-CH(2)Cl(2) mixture, together with the observation of a new emission band at 684 nm, likely arising from a charge transfer process involving reduction of Eu(III).

Electric field evolution of charge and energy transfer in molecule-doped polymer light-emitting diodes

The electroluminescence (EL) from tetramethyl ester of perylene-3,4,9,10-tetracarboxylic acid (TMEP)-doped poly(vinylcarbazole) (PVK) light-emitting diodes and their current-voltage characteristics were investigated. The results indicated that field-emission tunneling injection predominated in the ITO/TMEP:PVK/Al diodes at high applied voltages. With increasing the TMEP dopant density, the injection barrier for holes was slightly reduced. Under injection-limited conditions, the possible kinetic processes were discussed in view of the field evolution of the EL spectra and the energy level alignment in the diode configuration. With increasing the field intensity, different emission components varying their intensities in EL spectra indicates that both charge transfer and energy transfer occurred in TMEP-doped PVK layer. These transfer processes are influenced by varying the concentration of TMEP dopants as electron traps. The results indicate that the dynamic equilibrium among carrier recombination, charge transfer and energy transfer, can be adjusted by dopant concentration and external bias. This information helps to establish a design framework for host–dopant systems.

Excitation mechanism in polymer layers doped with tetra-methylester of perylene tetracarboxylicacid: influences of doping concentration and external bias

A spin-coated layer of poly(N-vinylcarbazole) (PVK) doped with tetra-methyl ester of perylene-3,4,9,10-tetracarboxylicacid (TMEP) is prepared, and the effects of dopant concentration and bias voltages on excitation mechanisms are studied through analyzing its emission characteristics. The investigation indicates that in photoluminescence (PL) cases energy and charge transfers between PVK and TMEP are cooperated for low dopant concentration, whereas the electroluminescence (EL) spectra imply that energy transfer is more important than charge trapping and transfer in these devices. For high dopant concentration, charge transfer is dominated in PL spectra but has a minor effect on EL spectra, and the external bias has less influence on the EL characteristics. A kinetic analysis is given to rationalize the experiment results.

Multiple Interactions in the Self-Association of Porphyrin Discotic Mesogens

The conformational preferences and the self-associational behaviors of two hemin-derived porphyrin compounds, a tetramethyl ester and a liquid crystalline tetrakis(3,5-didodecyloxyphenyl)ester, have been studied by UV/vis and (1)H NMR spectroscopy in solution. Results indicate that the 3,5-didodecyloxyphenyl units play an important role in both the conformational and the self-associational behaviors of the mesomorphic tetraester. In the monomeric, nonassociated species, the two propionic 3,5-didodecyloxyphenyl esters establish mutual CH/pi interactions that restrict the fluctuative behavior of the chains. In the dimeric, self-associated species, intermolecular CH/pi interactions occur in addition to the pi-pi stacking of the porphyrin cores. The temperature-dependent addition of side CH/pi interactions to the pi-pi stacking of the porphyrin rings accounts for the observed tightening and for the slower dynamics of the dimeric structure. The relationship between the self-associational behavior and the mesomorphism of the hemin-derived porphyrin tetraesters is also discussed.