- A dinuclear biomimetic Cu complex derived from l-histidine: synthesis and stereoselective oxidations
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A dinuclear copper(ii) complex derived from the chiral N6 ligand (2S,2′S)-N,N′-(ethane-1,2-diyl)bis(2-((1-methyl-1H-imidazol-4-ylmethyl)-amino)-3-(1-trityl-1H-imidazol-4-yl)propanamide) (EHI) was synthesized and studied as a catalyst in stereoselective oxidation reactions. The ligand contains two sets of tridentate binding units, each of them giving rise to a coordination set consisting of a pair of 5- and 6-membered chelate rings, connected by an ethanediamide linker. Stereoselectivity effects were studied in the oxidations of a series of chiral l/d biogenic catechols and the pair of l/d-tyrosine methyl esters, in this case as their phenolate salts. The oxidation of β-naphthol has also been studied as a model monooxygenase reaction. The catechol oxidation was investigated in a range of substrate concentrations at slightly acidic pH and exhibited a marked dependence on the concentration of the [Cu2EHI]4+ complex. This behavior has been interpreted in terms of an equilibrium between a monomeric and a dimeric form of the catalyst. Binding studies of l- and d-tyrosine were performed as a support for the interpretation of the stereoselectivity effects observed in the reactions. In general, [Cu2EHI]4+ exhibits a binding preference for the l- rather than the d-enantiomer of the substrates, but it appears that in the catecholase reaction the oxidation of the d-isomer occurs at a faster rate than for the l counterpart. The same type of enantio-discriminating behavior is observed in the oxidation of l-/d-tyrosine methyl esters. In this case the reaction produces a complex mixture of products; the main product consisting of a trimeric compound, likely formed by radical coupling reactions, has been isolated and characterized. The oxidation of β-naphthol yields an additional product of the expected quinone but labeling experiments with 18-O2 show no oxygen incorporation into the product, confirming that the oxidation likely proceeds through a radical mechanism.
- Perrone, Maria L.,Salvadeo, Elena,Lo Presti, Eliana,Pasotti, Luca,Monzani, Enrico,Santagostini, Laura,Casella, Luigi
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- Stabilized 111In-labeled sCCK8 analogues for targeting CCK2-receptor positive tumors: Synthesis and evaluation
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Radiolabeled cholecystokinin-8 (CCK8) peptide analogues can be used for peptide receptor radionuclide imaging and therapy for tumors expressing CCK2/gastrin receptors. Earlier findings indicated that sulfated CCK8 (sCCK8, Asp-Tyr(OSO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2) may have better characteristics for peptide receptor radionuclide therapy (PRRT) than gastrin analogues. However, sCCK8 contains an easily hydrolyzable sulfated tyrosine residue and two methionine residues which are prone to oxidation. Here, we describe the synthesis of stabilized sCCK8 analogues, resistant to hydrolysis and oxidation. Hydrolytic stability was achieved by replacement of the Tyr(OSO3H) moiety by a robust isosteric sulfonate, Phe(p-CH 2SO3H). Replacement of methionine by norleucine (Nle) or homopropargylglycine (HPG) avoided undesired oxidation side-reactions. The phenylalanine analogue Phe(p-CH2SO3H) of l-tyrosine, synthesized by a modification of known synthetic routes, was incorporated in three peptides: sCCK8[Phe2(p-CH2SO3H),Met 3,6], sCCK8[Phe2(p-CH2SO3H),Nle 3,6], and sCCK8[Phe2(p-CH2SO 3H),HPG3,6]. All peptides were N-terminally conjugated with the macrocyclic chelator DOTA (1,4,7,10-tetraazacyclododecane-N,N,N,N- tetraacetic acid) and radiolabeled with In-111. In vitro binding assays on CCK2R-expressing HEK293 cells revealed that all three peptides showed specific binding and receptor-mediated internalization, with binding affinity values (IC50) in the nanomolar range. In vitro oxidation studies demonstrated that peptides with Nle or HPG indeed were resistant to oxidation. In vivo targeting studies in mice with AR42J tumors showed that tumor uptake was highest for 111In-DOTA-sCCK8 and 111In-DOTA- sCCK8[Phe2(p-CH2SO3H),Nle3,6] (4.78 ± 0.64 and 4.54 ± 1.15%ID/g, respectively, 2 h p.i.). The peptide with the methionine residues replaced by norleucine (111In-DOTA- sCCK8[Phe2(p-CH2SO3H), Nle3,6]) showed promising in vivo characteristics and will be further investigated for radionuclide imaging and therapy of CCK2R-expressing tumors.
- Roosenburg, Susan,Laverman, Peter,Joosten, Lieke,Eek, Annemarie,Oyen, Wim J. G.,De Jong, Marion,Rutjes, Floris P. J. T.,Van Delft, Floris L.,Boerman, Otto C.
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- An auxin-tyrosine derivative based biocompatible supergelator: A template for fabrication of nanoparticles for sustained release of model drugs
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Bioinspired self-assembling peptides serve as powerful building blocks in the manufacturing of nanomaterials with tailored features. Inspired by the supergelating ability of naphthyl-Phe-OH (hydrogelator I), we synthesized naphthyl-Tyr-OH (hydrogelator II) and naphthyl-Trp-OH (hydrogelator III) with the objective of exploring the propensities of the phenolic OH of Tyr and the NH of the indole for controlling the gelation process. However, our experimental investigation reveals that hydrogelator II, containing Tyr as the aromatic core, shows an excellent gelation ability. But the Trp analogue fails to do so under similar conditions. To validate our results we performed MD simulation in an aqueous environment which significantly justifies that hydrogelator II exhibits a better hydrogelation ability than hydrogelators I and III. The characterisation of hydrogelator II was then performed in detail using various analytical and microscopic techniques and its biocompatibility was tested using an MTT assay. To examine the potentiality of hydrogelator II in drug delivery we developed hydrogel nanoparticles (HNPs) using the concept of self-assembly entirely governed by an ecofriendly approach i.e. weak interactions (like H-bonding, π-π and hydrophobic interactions). Our hydrogel nanoparticles display good release kinetics of the model drugs 5-fluorouracil and curcumin from the hydrogel matrix depending on their chemical structure, molecular weight and hydrophobicity. Thus our research shows that the choice of the core residue has a profound impact on the self-assembly process and thus on the gelation properties. Moreover, nanoparticles generated from our novel biocompatible hydrogelator II hold promise for future drug delivery applications.
- Tiwari, Priyanka,Basu, Anindya,Sahu, Sonu,Gound, Sadhna,Christman, Ryann M.,Tiwari, Amit K.,Trivedi, Piyush,DuttKonar, Anita
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- Synthesis, characterization and in vitro antimicrobial and biodegradability study of pseudo-poly(amino acid)s derived from N,N′-(pyromellitoyl)-bis- l-tyrosine dimethyl ester as a chiral bioactive diphenolic monomer
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In this investigation N,N′-(pyromellitoyl)-bis-l-tyrosine dimethyl ester (7) as a chiral bioactive diphenolic monomer was prepared in three steps. The aim of this work was to obtain novel optically and biologically active pseudo-poly(amino acid)s (PAA)s that are more soluble in common organic solvents while maintaining their high thermal stability. Thus, several new, highly soluble, thermally stable, optically active and biodegradable PAAs containing different amino acid moieties in the main chain were prepared with moderate molecular weights via direct polycondensation using tosyl chloride, pyridine and N,N′-dimethylformamide as a condensing agent. The resulting novel polymers were characterized with FT-IR, 1H-NMR, elemental and thermogravimetric analysis techniques. In addition, in vitro toxicity and biodegradability behavior of the diphenolic monomer 7, different synthetic diacids (3a-3e) and obtained PAAs, which were investigated in culture media, showed that the synthesized compounds and polymers derived from them are biologically active and biodegradable under a natural environment.
- Mallakpour, Shadpour,Tirgir, Farhang,Sabzalian, Mohammad R.
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- Fabrication of biodegradable poly(ester-amide)s based on tyrosine natural amino acid
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N,N'-Bis[2-(methyl-3-(4-hydroxyphenyl)propanoate)] isophthaldiamide (5), a novel diol monomer containing chiral group, was prepared by the reaction of S-tyrosine methyl ester (3) with isophthaloyl dichloride (4a). A new family of optically active and potentially biodegradable poly(ester-amide)s (PEAs) based on tyrosine amino acid were prepared by the polycondensation reaction of diol monomer 5 with several aromatic diacid chlorides. The resulting new polymers were obtained in good yields with inherent viscosities ranging between 0.25 and 0.42 dL/g and are soluble in polar aprotic solvents. They showed good thermal stability and high optical purity. The synthetic compounds were characterized and studied by FT-IR, 1H-NMR, specific rotation, elemental and thermogravimetric analysis (TGA) techniques and typical ones by 13C-NMR, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) analysis. Soil burial test of the diphenolic monomer 5, and obtained PEA6a, and soil enzymatic assay showed that the synthesized diol and its polymer are biologically active and probably biodegradable in soil environment. Springer-Verlag 2011.
- Abdolmaleki, Amir,Mallakpour, Shadpour,Borandeh, Sedigheh,Sabzalian, Mohammad R.
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- New 1,4-anthracene-9,10-dione derivatives as potential anticancer agents
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The amino-substituted anthracene-9,10-dione (9,10-anthraquinone) derivatives represent one of the most important classes of potential anticancer agents. To better understand the basic rules governing DNA sequence specificity, we have recently synthesized a new class of d- and l- aminoacyl-anthraquinone derivatives. We have tested these new compounds as cytotoxic agents, and we have correlated their activity with the configuration of the chiral aminoacyl moiety. Molecular modeling studies have been performed to compare the test drugs in terms of steric overlapping. (C) 2000 Elsevier Science S.A.
- Zagotto,Supino,Favini,Moro,Palumbo
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- Differentiation of natural and synthetic phenylalanine and tyrosine through natural abundance 2H nuclear magnetic resonance
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The natural abundance deuterium NMR characterization of samples of the amino acids tyrosine (1) and phenylalanine (2), examined as the acetylated methyl esters 4 and 6, has been performed with the aim to identify by these means the contribution in animals of the hydroxylation of the diet L-phenylalanine (2) to the formation of L-tyrosine (1), a feature previously revealed on the same samples through the determination of the phenolic δ18O values. The study, which includes also the NMR examination of benzoic acid (5) from 2 and of tyrosol (7) from 1, substantially fails in providing the required information because the mode of deuterium labeling of tyrosine samples of different origins is quite similar but indicates a dramatic difference in the deuterium labeling pattern of the two amino acids 1 and 2. The most relevant variation is with regard to the deuterium enrichments at the CH2 and CH positions, which are inverted in the two amino acids of natural derivation. Moreover, whereas the diastereotopic benzylic hydrogen atoms of L-tyrosine (1) appear to be equally deuterium enriched, in L-phenylalanine (2) the (D/H)3R > (D/H)3S. Similarly, benzoic acid (5) shows separate signals for the aromatic deuterium nuclei, which are quite indicative of the natural or synthetic derivation. The mode of deuterium labeling of the side chain of 1 and 2 is tentatively correlated to the different origins of the two amino acids, natural from animal sources for L-tyrosine and biotechnological probably from genetically modified microorganisms for L-phenylalanine.
- Brenna, Elisabetta,Fronza, Giovanni,Fuganti, Claudio,Pinciroli, Matteo
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- New Type of Aldol Condensations Catalyzed by Metal(II) Complexes of α-Amino Acid Esters and that with Cyclodextrin System
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The aldol condensation of p-nitrobenzaldehyde with acetone catalyzed by metal ccomplexes of α-amino acid esters proceeded under mild and neutral conditions to afford an enantiomeric excess aldol-type products, 4-hydroxy-4-(4-nitrophenyl)-2-butanone, along with same dehydrated products without any by-product.The most effective catalyst system was a zinc(II) complex of the tyrosine ethyl ester, Zn(II)-(TyrOEt)2 in MeOH.Complexes of the second-row transition metals were inadeguate for the reactions.Reactions at 30-40 deg C for 24 h were fovorable regarding the asymmetric induction.An H2O solvent was the best for aldol-type product formation without asymmetric induction.An assistand effect of cyclodextrins(especially, β-CD) on the catalysis of the Zn(II)-TyrOEt complex were thought to be observed.
- Watanabe, Ken-ichi,Yamada, Yoichi,Goto, Katsuhisa
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- Synthesis of d,l-amino acid derivatives bearing a thiol at the β-position and their enzymatic optical resolution
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Amino acids bearing a thiol group at the β-position are useful for native chemical ligation. Phenylalanine and tyrosine derivatives bearing a thiol group at the β-position were synthesized. Racemic phenylalanine and tyrosine were selected as starting materials and were introduced a bromo atom at the β-position by photoreaction. Subsequent substitution reaction of the bromo atom with p-methoxybenzylmercaptan yielded the corresponding amino acids bearing a thiol group at the β-position. Enzymatic optical resolution using l-aminoacylase and subsequent chemical conversion gave the corresponding optically pure l- and d-phenylalanine and tyrosine derivatives bearing a thiol group at the β-position.
- Morishita, Yasuhito,Kaino, Tomoka,Okamoto, Ryo,Izumi, Masayuki,Kajihara, Yasuhiro
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- Optimisation of conditions for O-benzyl and N-benzyloxycarbonyl protecting group removal using an automated flow hydrogenator
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A versatile, fully automated flow hydrogenator has been developed that is able to perform sequential flow optimisation experiments, flow library hydrogenation, or iterative scale-up hydrogenation. The behaviour of a palladium catalyst in effecting removal of O-benzyl and N-benzyloxycarbonyl protecting groups has been investigated. Significant observations relating to maintaining optimal throughput are reported. A small library of peptidic derivatives has been deprotected in high yield and purity.
- Knudsen, Kristian Rahbek,Holden, John,Ley, Steven V.,Ladlow, Mark
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- Enantioselective Aza-Diels Alder reaction catalyzed by clay supported Schiff base complex?
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Clay supported catalysts based on 2- hydroxy naphthaldehyde and amino acids, their copper and titanium complexes have been described. The catalysts were found to be active toward the synthesis of pyrano-, furanoquinolines through Aza-Diels Alder reaction. The catalysts gave good yield and high enantioselectivity. The catalysts were environmentally friendly, economical, synthetically robust and reusable.
- Kannan,Sreekumar
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- Phenylalanine and tyrosine methyl ester intramolecular interactions and conformational analysis by 1H NMR and infrared spectroscopies and theoretical calculations
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Amino acid conformational analysis in solution are scarce, since these compounds present a bipolar zwitterionic structure (+H 3NCHRCOO-) in these media. Also, intramolecular hydrogen bonds have been classified as the sole interactions governing amino acid conformational behavior in the literature. In the present work we propose phenylalanine and tyrosine methyl ester conformational studies in different solvents by 1H NMR and infrared spectroscopies and theoretical calculations. Both experimental and theoretical results are in agreement and suggest that the conformational behavior of the phenylalanine and tyrosine methyl esters are similar and are dictated by the interplay between steric and hyperconjugative interactions.
- Cormanich, Rodrigo A.,Ducati, Lucas C.,Tormena, Cláudio F.,Rittner, Roberto
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- L-O-(2-malonyl)tyrosine (L-OMT) a new phosphotyrosyl mimic suitably protected for solidphase synthesis of signal transduction inhibitory peptides
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A new phosphotyrosyl (pTyr) mimic L-O-(2-malonyl)tyrosine (L-OMT, 4) utilizes a malonyl structure in place of the parent phosphate group. This compound is stable to protein-tyrosine phosphatases and has advantages over phosphonate-based pTyr mimics in that protection of the malonyl group as its diester allows passage of the OMT across cell membranes, with subsequent esterase-mediated liberation of the free diacid once inside cells. Herein is reported the synthesis of Nα-Fmoc-L-OMT-O,O-(ferf-butyl)2 (5) for the solid-phase synthesis of L-OMT containing peptides as modulators of cellular signal transduction. Additionally included is the preparation of Nα-Fmoc-L-OMT-O,O-(n-butyl)2 (6) for the direct solid-phase synthesis of OMT-peptide diester prodrugs for use in cell-based studies.
- Ye, Bin
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- Stereostructure Clarifying Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone B. A Highly Acid-Labile N-Protecting Group for Amides ?
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The 5S, 8′R, and 10′R configurations of militarinone B (3), which is a natural product from Paecilomyces militaris, should equal those in its biosynthetic precursor, militarinone C. The configuration at C-1′ emerged from syntheses of the militarinone B candidates 1′′S- and 1′′R-(5S,8′R,10′R)-3 from the building blocks 9, 11, 14, and 15a while introducing TMB as a more acid-labile N-protecting group for β-ketoamides than DMB. Comparisons of 1′′S- and 1′′R-(5S,8′R,10′R)-3 with natural militarinone B (3; reisolated from Nature) revealed identity versus distinctness.
- Drescher, Christian,Brückner, Reinhard
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- Palladium-catalyzed oxalyl amide assisted direct ortho-alkynylation of arylalkylamine derivatives at δ and ε positions
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Palladium-catalyzed oxalyl amide directed ortho-alkynylation of arylalkylamine derivatives is reported for the first time. A wide variety of β-arylethamine and γ-arylpropamine derivatives are compatible with this protocol. This method provides a general means to synthesize substituted alkynylarylalkylamine derivatives, highlighting the ability of oxalyl amide in promoting C-H functionalization at unique δ and ε positions.
- Guan, Mingyu,Chen, Changpeng,Zhang, Jingyu,Zeng, Runsheng,Zhao, Yingsheng
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- Step-Up Synthesis of Periodic Mesoporous Organosilicas with a Tyrosine Framework and Performance in Horseradish Peroxidase Immobilization
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New amino-acid-bridged periodic mesoporous organosilicas (PMOs) were constructed by hydrolysis and condensation reactions under acid conditions in the presence of a template. The tyrosine bissilylated organic precursor (TBOS) was first prepared through a multistep reaction by using tyrosine (a natural amino acid) as the starting material. PMOs with the tyrosine framework (Tyr-PMOs) were constructed by simultaneously using TBOS and tetraethoxysilane as complex silicon sources in the condensation process. All the Tyr-PMOs materials were characterized by XRD, FTIR spectroscopy, N2 adsorption–desorption, TEM, SEM, and solid-state 29Si NMR spectroscopy to confirm the structure. The horseradish peroxidase (HRP) enzyme was first immobilized on these new Tyr-PMOs materials. Optimal conditions for enzyme adsorption included a temperature of 40 °C, a time of 8 h, and a pH value of 7. Furthermore, the novel Tyr-PMOs materials could store HRP for approximately 40 days and maintained the enzymatic activity, and the Tyr-PMOs–10 % HRP with the best immobilization effect could be reused at least eight times.
- Wang, Jianqiang,Zhang, Wenqi,Gu, Changqing,Zhang, Wenpei,Zhou, Man,Wang, Zhiwei,Guo, Cheng,Sun, Linbing
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- 12-Hydroxy stearic acid appended new amphiphilic scaffolds for selective capture of hydrogen halides through supramolecular hydrogelation
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12-Hydroxystearic acid (12-HSA) appended new amphiphilic scaffolds reveal excellent hydrogelation propensity in the presence of aqueous acids and vapors of HCl/HBr. This selective entrapment efficiency towards hydrogen halides demonstrates an unprecedented route for the successful removal of toxic chemicals, thus providing a safe and easy protocol for environment management. We anticipate that the halide derivative of the amphiphile plays a vital role in driving the self-assembly mechanism and eventually the hydrogelation phenomena.
- Sharma, Ankita,Gupta, Arindam,Tiwari, Priyanka,Basu, Anindya,Duttkonar, Anita
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- Bis(diamido)-bridged basket resorcin[4]arenes as enantioselective receptors for amino acids and amines
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On the research avenue opened by the rigidified double-spanned resorcin[4]arene 1, we have synthesized both enantiomers of the two chiral basket resorcin[4]arenes 3 and 4, each containing two 1,2-diaminocyclohexane and 1,2-diphenylethylenediamine bridges, respectively. In the new compounds, the aromatic rims assume the expected flattened cone arrangement, whereas two different conformations, tentatively designated as "open wings" and "folded wings", were attributed to the bridge substituents according to molecular modeling studies. In MSn (ESI) experiments, the proton-bonded diastereomeric [4·H·A]+ complexes with amino acidic guests (A) exhibited a pronounced selectivity towards the enantiomers of tyrosine methyl ester (tyrOMe) and amphetamine (amph), whereas the chirality of tryptophan (trp) was ineffective. Moreover, a kinetic study on the base-induced displacement of the guest revealed that the L-tyr OMe (and L-amph) enantiomer is faster displaced from the heterochiral [4·H·L-tyrOMe]+ (or [ent- 4·H·L-amph]+) complex than from the homochiral [ent-4·H·L-tyrOMe]+ (or [4·H· L-amph]+) one. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Botta, Bruno,D'Acquarica, Ilaria,Nevola, Laura,Sacco, Fabiola,Lopez, Zara Valbuena,Zappia, Giovanni,Fraschetti, Caterina,Speranza, Maurizio,Tafi, Andrea,Caporuscio, Fabiana,Letzel, Matthias C.,Mattay, Jochen
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- A small molecule peptidomimetic of spider silk and webs
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A peptidomimetic compound containing leucine, tyrosine and malonic acid self-assembles through various noncovalent interactions to form spider silk-like fibers at ambient temperature. From the high-density liquid, a liquid-solid phase transition is initiated at 20 °C and solidification occurs upon contact with air. The fiber has comprehensive mechanical strength and optical properties similar to spider silk, and can be used to mimic a natural spider web. This journal is
- Maji, Krishnendu,Sarkar, Rajib,Bera, Santu,Haldar, Debasish
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- In search of bioinspired hydrogels from amphiphilic peptides: A template for nanoparticle stabilization for the sustained release of anticancer drugs
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The development of potent stimuli-responsive hydrogels has rapidly expanded in the last decades due to their diversified applications in the field of biomedicines. In accordance with this drift, herein, we aimed at modulating a series of amphiphilic peptide analogues with the general formula Me-(CH2)14-CO-NH-CH(X)-COOH, where X = CH2Ph in hydrogelators I (l-Phe) and II (d-Phe) and X = CH2Ph(OH) in hydrogelator III (l-Tyr), which displayed an excellent propensity to immobilize water at room temperature with a minimum gelation concentration of 0.04%/0.05%/0.02% w/v for hydrogelators I-III, respectively, regardless of their configuration at the C-terminal centre. To validate this threshold concentration difference, we performed computational analysis that demonstrated the ability of the side-chains of hydrogelators I and III to remain highly planar with the methylene units of the amphiphile and aromatic rings, promoting favourable correspondence through van der Waals forces and pi-pi stacking. Consequently hydrogelators I and III self-assembled in an ordered organisation superior to hydrogelator II. Furthermore, the spectroscopic and microscopic experiments revealed that the hydrogelators manifested a β-sheet conformation and nanofibrous morphology at the supramolecular level. As observed visually and additionally confirmed by differential scanning calorimetry (DSC) and rheological measurements, the hydrogels exhibited thermo-reversibility, injectability and high mechanical strength. Importantly, these biomaterials were also found to be resistant towards proteolytic degradation and non-cytotoxic in the cell line HEK 293 using a dose-dependant cell viability assay. To date, the development of a structured approach for the release of drugs in a predictable manner from an optimised formulation, using peptide-based hydrogel nanoparticles as a delivery system remains in its infancy. Hence, we developed hydrogel nanoparticles (HNPs) with our fabricated amphiphilic peptides that exploited the weak noncovalent interactions for their fabrication, unlike other cross-linked polymers that require strong covalent or ionic bonds for their formation. Interestingly, the as-synthesized nanoparticles showed an unprecedented ability to release the anticancer drugs 5-fluoro uracil/doxorubicin at physiological conditions depending on the physico-chemical parameters of the drugs. We believe that the reported injectable, biocompatible, amphiphilic peptide-based hydrogels hold future promise as a potential tool to transport drugs to a targeted site at a greater concentration, thus relieving the patient from surgical injury and simultaneously aiding in a faster recovery.
- Mehra, Radha Rani,Tiwari, Priyanka,Basu, Anindya,Duttkonar, Anita
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- (4S)-p-hydroxybenzyl-1,3-oxazolidin-2-one as a solid-supported chiral auxiliary in asymmetric 1,3-dipolar cycloadditions
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Evans' chiral auxiliary was grafted onto both Merrifield and Wang resins and, after functionalisation, they were used as chiral dipolarophiles in a 1,3-dipolar cycloaddition involving both a nitrile oxide and a nitrone. The cycloadducts were cleaved and analysed by chiral HPLC: the recovered supported chiral oxazolidinone was functionalised and reused in further cycloadditions. The stereochemical results as well as the possibility of recycling the chiral linker supports the applicability of solid-supported chiral auxiliaries. (C) 2000 Elsevier Science Ltd.
- Faita, Giuseppe,Paio, Alfredo,Quadrelli, Paolo,Rancati, Fabio,Seneci, Pierfausto
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- Development of L-3-aminotyrosine suitably protected for the synthesis of a novel nonphosphorylated hexapeptide with low-nanomolar Grb2-SH2 domain-binding affinity
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Synthesis of orthogonally protected (2S)-2-amino-3-(3-amino-4-hydroxy- phenyl)-propionic acid (10) suitable for solid phase peptide synthesis and its first use for the preparation of nonphosphorylated Grb2-SH2 domain antagonists (4a-c) are reported. The 3-aminotyrosine containing sulfoxide-cyclized hexapeptide (4b) exhibited potent Grb2-SH2 domain binding affinity with IC 50=50nM, which represents the highest affinity yet reported for a peptide inhibitor against Grb2-SH2 domain with only 6 residues free of phosphotyrosine or phosphotyrosine mimics. This potent small peptidomimetic 4b may be representative of a new class of therapeutically relevant Grb2-SH2 domain-directed agents, and acts as a chemotherapeutic lead for the treatment of erbB2-related cancers.
- Song, Yan-Li,Roller, Peter P.,Long, Ya-Qiu
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- Synthesis of amphiphilic meso -tetrasubstituted porphyrin-L-amino acid and -heterocyclic conjugates based on m -THPP
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Two series of amphiphilic meso-tetrasubstituted porphyrin conjugates based on 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (m-THPP) covalently linked to L-amino acids and heterocycles were synthesized efficiently in the context of a program targeting new photosensitizers for PDT. 5,10,15-Tris(3-hydroxyphenyl)-20-(3-oxyacetic acid)phenyl]porphyrin and the respective trihexyl ether derivatives were conjugated with polar and non-polar natural L-amino acids such as glycine, L-proline, and L-tyrosine via an amide bond linker using N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uroniumhexafluorophosphate in diisopropylethylamine (HBTU/DIPEA). m-THPP was also conjugated with heterocyclic systems such as indole 3-acetic acid, 4-methylthiazole-5-carboxylic acid, and thiophene-2-carboxylic acid via ester linker using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride in N-hydroxysuccinamide or 1-hydroxybenzotriazole (EDCI, NHS or HOBt). The members of the two series were obtained in good yields and characterized by UV-vis, HRMS MALDI-TOF, 1H NMR and 13C NMR spectroscopy.
- Sweed, Ayman M. K.,Senge, Mathias O.,Atta, Sanaa M. Sh.,Farrag, Dalia S.,Abdel-Rahman, Abdel-Rahman H.,Shaker, Yasser M.
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- Novel PCU cage diol peptides as potential targets against wild-type CSA HIV-1 protease: Synthesis, biological screening and molecular modelling studies
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We have synthesized a series of novel pentacycloundecane cage diol diacid (PCU diol diacid) incorporated C 2-symmetric peptides. Their activity against the resistance-prone wild-type C-South African (C-SA) HIV protease (HIV PR) is reported. These compounds were obtained in moderate yields of 42-72 %. Amongst the nine compounds reported herein only compound 6, 7, 10 and 11 showed moderate IC50 values of 5-10 μM. Peptides 7 and 10 contain two phenylglycine and two tryptophan amino acids, respectively as side arms to the cage diol. Phenylglycine is a non-natural amino acid. Docking and molecular dynamics (MD) studies were carried out to understand the binding mode of the PCU moiety at the active site of the HIV PR enzyme. The computational results show that the cage diol peptide fits quite comfortably inside the active site of the enzyme. Not much movement is observed during the MD simulation and the hydrogen bonds that develop between the inhibitor and the enzyme pocket suggest that the inhibitor/HIV PR complex is stable at room temperature.
- Karpoormath, Rajshekhar,Sayed, Yasien,Govender, Thavendran,Kruger, Hendrik G.,Soliman, Mahmoud E. S.,Maguire, Glenn E. M.
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- Gas-phase enantioselectivity of chiral amido[4]resorcinarene receptors
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Diastereomeric proton-bound [1LHA]+ complexes between selected amino acids (A = phenylglycine (Phg), tryptophan (Trp), tyrosine methyl ester (TyrOMe), threonine (Thr), and allothreonine (AThr)) and a chiral amido[4]resorcinarene receptor (1L) display a significant enantioselectivity when undergoing loss of the amino acid guest A by way of the enantiomers of 2-aminobutanes (B) in the gas phase. The enantioselectivity of the B-to-A displacement is ascribed to a combination of thermodynamic and kinetic factors related to the structure and the stability of the diastereomeric [1LHA]+ complexes and of the reaction transition states. The results of the present and previous studies allow classification of the [1LHA]+ complexes in three main categories wherein: i) guest A does not present any additional functionalities besides the amino acid one (alanine (Ala), Phg, and phenylalanine (Phe)) ; ii) guest A presents an additional alcohol function (serine (Ser), Thr, and AThr); and iii) guest A contains several additional functionalities on its aromatic ring (tyrosine (Tyr), TyrOMe, Trp, and 3,4-dihydroxyphenylalanine (DOPA)). Each category exhibits a specific enantioselectivity depending upon the predominant [1 LHA]+ structures and the orientation of the 2-aminobutane reactant in the relevant adducts observed. The results may contribute to the understanding of the exceptional selectivity and catalytic properties of enzyme mimics towards unsolvated biomolecules.
- Botta, Bruno,Caporuscio, Fabiana,D'Acquarica, Ilaria,Delle Monache, Giuliano,Subissati, Deborah,Tafi, Andrea,Botta, Maurizio,Filippi, Antonello,Speranza, Maurizio
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- Site-Specific Incorporation of a Photoactivatable Fluorescent Amino Acid
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Photoactivatable fluorophores are emerging optical probes for biological applications. Most photoactivatable fluorophores are relatively large in size and need to be activated by ultraviolet light; this dramatically limits their applications. To introduce photoactivatable fluorophores into proteins, recent investigations have explored several protein-labeling technologies, including fluorescein arsenical hairpin (FlAsH) Tag, HaloTag labeling, SNAPTag labeling, and other bioorthogonal chemistry-based methods. However, these technologies require a multistep labeling process. Here, by using genetic code expansion and a single sulfur-for-oxygen atom replacement within an existing fluorescent amino acid, we have site-specifically incorporated the photoactivatable fluorescent amino acid thioacridonylalanine (SAcd) into proteins in a single step. Moreover, upon exposure to visible light, SAcd can be efficiently desulfurized to its oxo derivatives, thus restoring the strong fluorescence of labeled proteins.
- Tang, Juan,Yu, Chenfei,Loredo, Axel,Chen, Yuda,Xiao, Han
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p. 501 - 504
(2020/11/03)
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- Synthesis and Bioactivity of a Macrocidin B Stereoisomer
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A stereoisomer of macrocidin B, a presumed metabolite of the fungus Phoma macrostoma, was synthesized in 18 steps and 2.7% yield from protected l-tyrosine that was N-β-ketoacylated with a fully functionalized octanoyl Meldrum's acid. Dieckmann condensation gave a 3-acyltetramic acid, which was macrocyclized via Williamson etherification between the phenol and epi-bromohydrin termini. This macrocidin B stereoisomer showed a weaker herbicidal effect than macrocidin A and no similar inhibitory effect on biofilms of Staphylococcus aureus.
- Weber, Stefanie E.,Ga?, Juliane,Zeng, Haoxuan,Erb-Brinkmann, Maike,Schobert, Rainer
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supporting information
p. 8273 - 8276
(2021/10/25)
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- Transition Metal-Free N-Arylation of Amino Acid Esters with Diaryliodonium Salts
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A transition metal-free approach for the N-arylation of amino acid derivatives has been developed. Key to this method is the use of unsymmetric diaryliodonium salts with anisyl ligands, which proved important to obtain high chemoselectivity and yields. The scope includes the transfer of both electron deficient, electron rich and sterically hindered aryl groups with a variety of different functional groups. Furthermore, a cyclic diaryliodonium salt was successfully employed in the arylation. The N-arylated products were obtained with retained enantiomeric excess.
- Kervefors, Gabriella,Kersting, Leonard,Olofsson, Berit
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p. 5790 - 5795
(2021/03/08)
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- Highly Stable Zr(IV)-Based Metal-Organic Frameworks for Chiral Separation in Reversed-Phase Liquid Chromatography
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Separation of racemic mixtures is of great importance and interest in chemistry and pharmacology. Porous materials including metal-organic frameworks (MOFs) have been widely explored as chiral stationary phases (CSPs) in chiral resolution. However, it remains a challenge to develop new CSPs for reversed-phase high-performance liquid chromatography (RP-HPLC), which is the most popular chromatographic mode and accounts for over 90% of all separations. Here we demonstrated for the first time that highly stable Zr-based MOFs can be efficient CSPs for RP-HPLC. By elaborately designing and synthesizing three tetracarboxylate ligands of enantiopure 1,1′-biphenyl-20-crown-6, we prepared three chiral porous Zr(IV)-MOFs with the framework formula [Zr6O4(OH)8(H2O)4(L)2]. They share the same flu topological structure but channels of different sizes and display excellent tolerance to water, acid, and base. Chiral crown ether moieties are periodically aligned within the framework channels, allowing for stereoselective recognition of guest molecules via supramolecular interactions. Under acidic aqueous eluent conditions, the Zr-MOF-packed HPLC columns provide high resolution, selectivity, and durability for the separation of a variety of model racemates, including unprotected and protected amino acids and N-containing drugs, which are comparable to or even superior to several commercial chiral columns for HPLC separation. DFT calculations suggest that the Zr-MOF provides a confined microenvironment for chiral crown ethers that dictates the separation selectivity.
- Jiang, Hong,Yang, Kuiwei,Zhao, Xiangxiang,Zhang, Wenqiang,Liu, Yan,Jiang, Jianwen,Cui, Yong
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supporting information
p. 390 - 398
(2021/01/13)
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- Guanidine-containing compound as well as preparation method and application thereof
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The invention discloses a cyanoguanidine-containing compound as well as a preparation method and application thereof. The invention also discloses a composition containing the cyanoguanidine-structured compound (I) or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier. The invention also discloses application thereof in preparation of analgesic drugs. The compounds of the invention are useful in the treatment of various pain.
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Paragraph 0038-0041; 0092-0094
(2021/11/26)
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- Structure-Elucidating Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone C §
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The (polyenoyl)tetramic acid militarinone C (1) heads a family of seven members. Before our work, the configuration of C-5 was unknown whereas the configurations of C-8′ and C-10′ were either (R,R) or (S,S). We synthesized the four stereoisomers of constitution 1, which conform with these insights. This included cross-coupling both enantiomers of the western building block (8) with both enantiomers of the eastern building block (9). The specific rotations of the resulting 1 isomers suggested that natural 1 is configured like the coupling partners (S)-8 and (R,R)-9. This conclusion was corroborated by degrading natural 1 to alcohol 35 and by proving its configurational identity with synthetic (R,R)-35.
- Brückner, Reinhard,Drescher, Christian,Hamburger, Matthias,Keller, Morris,Potterat, Olivier
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supporting information
(2020/03/30)
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- Preparation method of rosastat key intermediate
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The invention provides a preparation method of a rosastat key intermediate. The intermediate I is 4-hydroxy-1-methyl-7-phenoxy isoquinoline-3-carboxylic ester. The preparation method comprises the following steps: with tyrosine as an initial raw material, sequentially carrying out esterification, acylation, etherification, cyclization, aromatization and oxidation rearrangement reaction to preparethe rosastat key intermediate. The preparation method has the advantages of cheap and easily available raw materials, environmental protection, avoiding of use of phosphorus oxychloride, polyphosphoric acid and other environmentally unfriendly reagents in the cyclization reaction, simple process, simple operation and mild reaction conditions; and the method has the advantages of less three wastesand higher product yield and purity, and is suitable for industrial production.
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Paragraph 0045-0048
(2020/09/09)
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- CALPAIN MODULATORS AND THERAPEUTIC USES THEREOF BACKGROUND
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Disclosed herein are small molecule calpain modulators, pharmaceutical compositions, preparation methods and their use as therapeutic agents. The therapeutic agents can be used for treating fibrotic disease or a resulting secondary disease state or condition. The small molecules can inhibit calpain through contact with CAPN1, CAPN2, and/or CAPN9 enzymes.
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Paragraph 0235; 0237
(2019/11/28)
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- [...] his preparation method
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The invention discloses a preparation method of Roxadustat. The preparation steps are as follows: the Roxadustat is prepared from tyrosine through esterification, etherification, cyclization, dehydrogenation, oxidative rearrangement and acylation reaction. The preparation method has the advantages that the raw materials are easily obtained; the process is simple; and the preparation method is economic and environmental-friendly, and is suitable for industrialized production.
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Paragraph 0038-0039
(2018/05/24)
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- Tyrosine methyl ester modified N-(8-quinolyl)acetamide compound and synthetic method and application thereof
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The invention discloses a tyrosine methyl ester modified N-(8-quinolyl)acetamide compound and a synthetic method and application thereof as well as a method for detecting the concentration of copper ions and iron ions. The structural formula of the compound is as shown in the description.
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Paragraph 0054; 0057; 0061
(2018/07/30)
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- Exciton-Coupled Circular Dichroism Characterization of Monotopically Binding Guests in Host?Guest Complexes with a Bis(zinc porphyrin) Tweezer
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A stiff-stilbene-linked bisporphyrin tweezer with inherent helicity was used for exciton-coupled circular dichroism (ECCD) characterization of a series of monotopically binding amine guest molecules. CD signals were observed for a variety of monoamines at relatively low tweezer/amine (host/guest) ratios between 1 : 10 to 1 : 70. For the amines producing the most intense CD signals, a binding stoichiometry of 1 : 2 was found. A likely explanation is the presence of guest-guest interactions in the complexes. This is supported by the correlation observed between CD signal intensity and magnitude of possible noncovalent binding between the guests, which can be divided into three groups showing no, moderate and strong response, respectively. Further support for this rationalization comes from molecular modelling.
- Olsson, Sandra,Sch?fer, Clara,Blom, Magnus,Gogoll, Adolf
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p. 1169 - 1178
(2019/01/04)
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- Elucidating the Reaction Pathway of Decarboxylation-Assisted Olefination Catalyzed by a Mononuclear Non-Heme Iron Enzyme
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Installation of olefins into molecules is a key transformation in organic synthesis. The recently discovered decarboxylation-assisted olefination in the biosynthesis of rhabduscin by a mononuclear non-heme iron enzyme (P.IsnB) represents a novel approach in olefin construction. This method is commonly employed in natural product biosynthesis. Herein, we demonstrate that a ferryl intermediate is used for C-H activation at the benzylic position of the substrate. We further establish that P.IsnB reactivity can be switched from olefination to hydroxylation using electron-withdrawing groups appended on the phenyl moiety of the analogues. These experimental observations imply that a pathway involving an initial C-H activation followed by a benzylic carbocation species or by electron transfer coupled β-scission is likely utilized to complete C=C bond formation.
- Yu, Cheng-Ping,Tang, Yijie,Cha, Lide,Milikisiyants, Sergey,Smirnova, Tatyana I.,Smirnov, Alex I.,Guo, Yisong,Chang, Wei-Chen
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supporting information
p. 15190 - 15193
(2018/11/23)
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- A Bioinspired Synthesis of Polyfunctional Indoles
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Polyfunctional indoles bearing substituents at C5 and C6 are prevalent in natural products, pharmaceuticals, agrochemicals, and materials. Owing to the remoteness of the C5 and C6 positions, indoles of this family can be difficult to prepare, and often require multistep syntheses. Herein, we describe a concise process that converts simple derivatives of tyrosine into 5,6-difunctionalized indoles by direct oxidation of C?H, N?H, and O?H bonds. Our work draws inspiration from the biosynthetic polymerization of tyrosine to make melanin pigments, but makes an important departure to provide well-defined indole heterocycles.
- Huang, Zheng,Kwon, Ohhyeon,Huang, Haiyan,Fadli, Aziz,Marat, Xavier,Moreau, Magali,Lumb, Jean-Philip
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supporting information
p. 11963 - 11967
(2018/09/11)
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- Novel thiazolidinedione-5-acetic-acid-peptide hybrid derivatives as potent antidiabetic and cardioprotective agents
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Thiazolidinediones (TZDs) are one of the important clinically established antidiabetic agents. Amino-acid and peptides have an advantage of better target selectivity and specificity. As hybrids, they also improved absorption and showed better bioavailability, which in turn makes them safer. Hence, here an effort has been made to synthesize hybrids of thiazolidinedione with amino-acids and peptides and evaluate their antidiabetic and cardioprotective effect in streptozotocin-nicotinamide (STZ-NA) induced Type 2 diabetes mellitus (T2DM) rat models. A series of 14 thiazolidinedione-5-acetic acid hybrids with of different amino-acids and peptide combinations were synthesized, characterized and further screened for antidiabetic and cardioprotective activity. Among all, six compounds T1 (SSDMA1), T4 (SSDMA4), T5 (SSDMA5), T7 (SDMA13), T9 (SSDMA15) and T13 (SSDMA49) showed better antioxidant activity and comparable % glucose uptake by yeast cells. Hence, the in vivo antidiabetic screening was done for these six compounds. Among all six T1, T7, T13 showed significant blood glucose level decrease compared to standard pioglitazone HCl. Also T1, T7 and T13 showed better antioxidant activity with lower IC50 value than standard ascorbic acid, and hence in vivo cardioprotective studies were done for these. The ECG studies showed that T1 (SSDMA1) and T7 (SSDMA13) were better effective than SDMA49 (T13) in restoring the normal functioning of the heart, thus may help in preventing the development of diabetic cardiomyopathy (DCM) and controlling T2DM.
- Maji,Samanta
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p. 1163 - 1172
(2017/02/23)
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- The impact of sugar and fatty acid on the bioactivity of N-fatty acyl-L-tyrosine aglycone
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Abstract: In the present study, a series of fatty acids-based (short, medium and long unsaturated chains) glycosylated N-fatty acyl-L-tyrosines and N-lipoyl-L-tyrosine methyl esters were synthesized and evaluated for their cytotoxic and antimicrobial activities. The aglycone moiety was synthesized using different chemical reagents. The glycosylation of aglycone moiety with different carbohydrates was performed using the Lewis acid, BF 3.Et 2O. All the synthesized compounds were tested against a panel of four cancer cell lines. The glycosylated N-fatty acyl-L-tyrosines showed moderate activity against all the cell lines and the IC 50 values were in the range of 15.6-45.6μM. However, the oleic acid analogues (10a, 10d) exhibited IC 50 values of 15.6, 17.6μM, respectively, against MDA-MB-231 cell line. Glycosylated N-lipoyl-L-tyrosine methyl esters (6b–6d) showed promising activity against all the tested cell lines and the IC 50 values ranged between 9.4-13.8μM. The compound 6d exhibited significant cytotoxicity and IC 50 values were 10.5, 9.4, 10.9 and 12.1μM against A549, PC3, MDA-MB-231 and HepG2 cell lines, respectively. Moreover, the non-glycosylated N-fatty acyl-L-tyrosine and methyl N-fatty acyl-L-tyrosinate derivatives showed excellent and moderate antimicrobial activity against some of the tested bacterial strains. Graphical Abstract: The glycosylated N-fatty acyl-L-tyrosines with short, medium and long chain unsaturated fatty acids and glycosylated N-lipoyl-L-tyrosine methyl esters were synthesized and further evaluated for their biological activities to examine the impact of sugar and fatty acid on the bioactivity of N-fatty acyl-L-tyrosine derivatives. [Figure not available: see fulltext.].
- Vudhgiri, Srikanth,Prasad,Poornachandra,Ganesh Kumar,Anjaneyulu,Sirisha,Jala, Ram Chandra Reddy
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p. 663 - 677
(2017/06/29)
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- Improving target amino acid selectivity in a permissive aminoacyl tRNA synthetase through counter-selection
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The amino acid acridon-2-ylalanine (Acd) can be a valuable probe of protein dynamics, either alone or as part of a F?rster resonance energy transfer (FRET) or photo-induced electron transfer (eT) probe pair. We have previously reported the genetic incorporation of Acd by an aminoacyl tRNA synthetase (RS). However, this RS, developed from a library of permissive RSs, also incorporates N-phenyl-aminophenylalanine (Npf), a trace byproduct of one Acd synthetic route. We have performed negative selections in the presence of Npf and analyzed the selectivity of the resulting AcdRSs by in vivo protein expression and detailed kinetic analyses of the purified RSs. We find that selection conferred a ~50-fold increase in selectivity for Acd over Npf, eliminating incorporation of Npf contaminants, and allowing one to use a high yielding Acd synthetic route for improved overall expression of Acd-containing proteins. More generally, our report also provides a cautionary tale on the use of permissive RSs, as well as a strategy for improving selectivity for the target amino acid.
- Sungwienwong, Itthipol,Hostetler, Zachary M.,Blizzard, Robert J.,Porter, Joseph J.,Driggers, Camden M.,Mbengi, Lea Z.,Villegas, José A.,Speight, Lee C.,Saven, Jeffery G.,Perona, John J.,Kohli, Rahul M.,Mehl, Ryan A.,Petersson, E. James
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supporting information
p. 3603 - 3610
(2017/07/07)
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- Unveiling and tackling guanidinium peptide coupling reagent side reactions towards the development of peptide-drug conjugates
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Peptide coupling reagents and especially uronium/guanidinium salts have been extensively utilized in solid-phase peptide synthesis. However, the impact of these reagents in solution phase synthesis, normally used in the formation of peptide-drug conjugates (PDCs), has not been fully explored. Herein, we identified that when guanidinium salts are used in classical peptide coupling conditions, besides leading to the formation of amide bonds, a uronium derivative can also be installed on specific amino acid scaffolds. The formation of this side product depends on the reaction conditions, as also on the nucleophilicity of the susceptible groups. Conditions to avoid this side product formation and a putative reaction mechanism describing its formation are reported.
- Vrettos, Eirinaios I.,Sayyad, Nisar,Mavrogiannaki, Eftychia M.,Stylos, Evgenios,Kostagianni, Androniki D.,Papas, Serafim,Mavromoustakos, Thomas,Theodorou, Vassiliki,Tzakos, Andreas G.
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p. 50519 - 50526
(2017/11/10)
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- Method for synthesizing tyrosine framework type periodic mesoporous organosilicas materials
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The invention relates to a method for preparing tyrosine framework type periodic mesoporous organosilicas materials. The method for synthesizing the tyrosine framework type periodic mesoporous organosilicas materials includes esterifying tyrosine in methanol by the aid of thionyl chloride; carrying out acrylation on the tyrosine by the aid of hydrazine hydrate and carrying out reaction on the tyrosine and isocyanic acid propyltriethoxysilane to obtain tyrosine organosilicas precursors; hydrolyzing the tyrosine organosilicas precursors and surfactants under acidic conditions to form PMO (periodic mesoporous organosilicas) materials; removing the surfactants from the PMO materials by means of extraction to ultimately form PMO materials with specific morphological structures. The tyrosine is used as a substrate. The methanol is used as a solvent. The method has the advantages synthesis reaction raw materials are simple and are easily available, synthesis operation is simple and convenient and is easy to implement, and the method is high in yield and low in energy consumption and is safe and inexpensive; the tyrosine framework type periodic mesoporous organosilicas materials prepared by the aid of the method have important application prospects in the fields of biosensors, catalyst carriers, adsorbents, sustained-release medicine capsules, chromatographic separation and the like.
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Paragraph 0024
(2017/08/29)
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- Sulfotyrosine dipeptide: Synthesis and evaluation as HIV-entry inhibitor
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Human immunodeficiency virus type 1 (HIV-1) is responsible for the worldwide AIDS pandemic. Due to the lack of prophylactic HIV-1 vaccine, drug treatment of the infected patients becomes essential to reduce the viral load and to slow down progression of the disease. Because of drug resistance, finding new antiviral agents is necessary for AIDS drug therapies. The interaction of gp120 and co-receptor (CCR5/CXCR4) mediates the entry of HIV-1 into host cells, which has been increasingly exploited in recent years as the target for new antiviral agents. A conserved co-receptor binding site on gp120 that recognizes sulfotyrosine (sTyr) residues represents a structural target to design novel HIV entry inhibitors. In this work, we developed an efficient synthesis of sulfotyrosine dipeptide and evaluated it as an HIV-1 entry inhibitor.
- Ju, Tong,Hu, Duoyi,Xiang, Shi-Hua,Guo, Jiantao
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p. 105 - 111
(2016/08/02)
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- STEAROYL AMINO ACID SALT AND PREPARATION METHOD AND APPLICATION THEREOF
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A stearoyl amino acid salt having a structural formula of the general formula (I), wherein R1 is H or an aromatic base capable of being substituted by one or more substituents, or a C1-4 straight chain or an alkyl with a branched chain, the substituent being an alcoholic hydroxyl group or a phenolic hydroxyl group; and R2 is a C11-25 saturated or unsaturated aliphatic group. Also provided are methods of preparing the stearoyl amino acid salt, and methods of using the stearoyl amino acid salt. Compared to a prototype drug stearoyl amino acid, the stearoyl amino acid salt described herein has excellent physicochemical properties, good stability, high relative bioavailability, a strong drug effect and a high safety factor. It is thus expected to become a candidate for clinical treatment of neurodegenerative diseases and acute brain injury, and a clinical drug for weight loss, thus having broad application prospects.
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Paragraph 0066; 0067; 0068
(2016/11/24)
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- GLYCOAMINO ACID AND USE THEREOF
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An object of the present invention is to provide glycoamino acid as an amino acid precursor with improved properties (particularly water-solubility, stability in water, bitter taste etc.). The present invention relates to a compound represented by the formula (I): wherein each symbol is as defined in the DESCRIPTION, or a salt thereof.
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Page/Page column 12
(2016/08/17)
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- BISAMIDE COMPOUNDS AS ALLOSTERIC EFFECTORS FOR REDUCING THE OXYGEN-BINDING AFFINITY OF HEMOGLOBIN
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This invention relates to compounds of Formula (I) and pharmaceutically acceptable salts thereof, which are allosteric effectors that reduce the oxygen-binding affinity of hemoglobin, which can enhance the efficacy of radiation therapy for cancer and which are useful for the treatment of ischemia and other conditions.
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Paragraph 0239-0240
(2016/12/01)
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- SAR of sponge-inspired hemibastadin congeners inhibiting blue mussel phenoloxidase
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Hemibastadin derivatives, including the synthetically-derived 5,5′-dibromohemibastadin-1 (DBHB), are potent inhibitors of blue mussel phenoloxidase (PO), which is a key enzyme involved in the firm attachment of this invertebrate to substrates and, thus, a promising molecular target for anti-fouling research. For a systematic investigation of the enzyme inhibitory activity of hemibastadin derivatives, we have synthesized nine new congeners, which feature structural variations of the DBHB core structure. These structural modifications include, e.g., different halogen substituents present at the aromatic rings, different amine moieties linked to the (E)-2-(hydroxyimino)-3-(4-hydroxyphenyl)propionic acid, the presence of free vs. substituted aromatic hydroxyl groups and a free vs. methylated oxime group. All compounds were tested for their inhibitory activity towards the target enzyme in vitro, and IC50 values were calculated. Derivatives, which structurally closely resemble sponge-derived hemibastadins, revealed superior enzyme inhibitory properties vs. congeners featuring structural moieties that are absent in the respective natural products. This study suggests that natural selection has yielded structurally-optimized antifouling compounds.
- Niemann, Hendrik,Hagenow, Jens,Chung, Mi-Young,Hellio, Claire,Weber, Horst,Proksch, Peter
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p. 3061 - 3071
(2015/06/08)
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- Synthesis, bioactivity, docking and molecular dynamics studies of furan-based peptides as 20s proteasome inhibitors
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Proteasome inhibitors are promising compounds for a number of therapies, including cardiovascular and eye diseases, diabetes, and cancers. We previously reported a series of furanbased peptidic inhibitors with moderate potencies against the proteasome b5 subunit, hypothesizing that the C-terminal furyl ketone motif could form a covalent bond with the catalytic residue, threonine 1. In this context, we describe further optimizations of the furan-based peptides, and a series of dipeptidic and tripeptidic inhibitors were designed and synthesized, aiming at improved potency and better solubility. Most of the tripeptidic inhibitors demonstrated improved potency and selectivity as b5 subunit inhibitors in both enzymatic and cellular assays, and good antineoplastic activities in various tumor cell lines were also observed. However, no inhibitory effects were observed for the dipeptidic compounds, which led us to presume that a noncovalent binding mode is adopted. Docking studies and molecular dynamics simulations were carried out to verify this presumption, with results showing that the distance between the furyl ketone motif and Thr1 is slightly too long to form covalent bond.
- Sun, Qi,Xu, Bo,Niu, Yan,Xu, Fengrong,Liang, Lei,Wang, Chao,Yu, Jiapei,Yan, Gang,Wang, Wei,Jin, Hongwei,Xu, Ping
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p. 498 - 510
(2015/03/18)
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- BISAMIDE COMPOUNDS AS ALLOSTERIC EFFECTORS FOR REDUCING THE OXYGEN-BINDING AFFINITY OF HEMOGLOBIN
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This invention relates to compounds of Formula (I) and pharmaceutically acceptable salts thereof, which are allosteric effectors that reduce the oxygen-binding affinity of hemoglobin, which can enhance the efficacy of radiation therapy for cancer and which are useful for the treatment of ischemia and other conditions.
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Page/Page column 43
(2015/07/23)
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- Biotinylated amphiphile-single walled carbon nanotube conjugate for target-specific delivery to cancer cells
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The present work reports the specific targeting of cancerous cells using a non-covalently water dispersed nanoconjugate of biotinylated amphiphile-single walled carbon nanotube (SWNT). The fundamental approach involves incorporation of the biotin into the architecture of the carbon nanotube (CNT) dispersing agent to develop a multifaceted delivery vehicle having a high colloidal stability, substantial cell viability and targeted specificity towards cancer cells. A three way functionalization strategy was employed to introduce a C-16 hydrophobic segment, polyethylene glycol hydrophilic fragment and biotin as the target-specific unit at the -OH, -COOH and -NH2 terminals of l-tyrosine, respectively. The newly developed neutral amphiphile exhibited an efficient SWNT dispersion (72%) in water, significant viability of different mammalian cells (Hela, HepG2, CHO and HEK-293) up to 48 h and also media stability. Most importantly, the biotinylated amphiphile-SWNT dispersion successfully transported the fluorescently labelled Cy3-oligoneucleotide (loaded on the surface of CNT) inside the cancerous Hela, HepG2 cells after 3 h of incubation, in contrast to CHO and HEK-293 cells (devoid of overexpressed biotin receptors). The presence of the biotin moiety in the cellular transporters facilitated the internalization of cargo due to the overexpressed biotin receptors in the cancer cells. Importantly, this nanohybrid was also capable of specifically transporting the anticancer drug doxorubicin to cancer cells, which led to the significant killing of Hela cells compared to the normal CHO cells. Thus, the receptor-mediated specific transportation of cargo into cancer cells was possible only due to the biotinylated CNT dispersing agent. To the best of our knowledge this is the first reported amino acid based biotinylated small amphiphilic molecule that non-covalently dispersed SWNTs and the corresponding nanoconjugate showed excellent cell viability, antibiofouling properties and the desired target-specific drug delivery.
- Brahmachari, Sayanti,Ghosh, Moumita,Dutta, Sounak,Das, Prasanta Kumar
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p. 1160 - 1173
(2014/03/21)
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- Effect of the 4′-substituted phenylalanine moiety of sansalvamide A peptide on antitumor activity
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Eight sansalvamide A peptide analogues with 4′-fluoride, 4′-chloride, 4′-bromide, 4′-iodide, and 4′- methoxyphenylalanine moieties were synthesized. The effect of these para-substitutions of sansalvamide A peptide on their cytotoxicity was evaluated using HCT-116, MDA-MB-231, HT-29, HCT-15, K562, HeLa, and A549 cell lines. The 4′-methoxyphenylalanine analog of sansalvamide A peptide was found to be a promising antitumor agent.
- Liu, Shouxin,Yang, Yihua,Zhao, Cuiran,Huang, Jing,Han, Chunyu,Han, Jianrong
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p. 463 - 467
(2014/04/17)
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- Asymmetric synthesis of fortucine and reassignment of its absolute configuration
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A convergent and enantioselective synthesis of fortucine was achieved from the starting materials tyrosine methyl ester and 3-hydroxy-4- methoxybenzaldehyde. The synthesis is based on two key steps mediated by a hypervalent iodine reagent. This work has enabled us to reassign the absolute configuration of the natural product reported in the literature. A multi-tool for total synthesis: A convergent and enantioselective synthesis of fortucine was achieved from the starting materials tyrosine methyl ester and 3-hydroxy-4-methoxybenzaldehyde. The synthesis is based on two key steps mediated by a 'multi-tool' hypervalent iodine reagent (see scheme).
- Beaulieu, Marc-Andre,Ottenwaelder, Xavier,Canesi, Sylvain
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supporting information
p. 7581 - 7584
(2014/07/07)
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- The synthesis of 13C9-15N-labeled 3,5-diiodothyronine and thyroxine
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Thyroid hormones undergo extensive metabolism to regulate hormone activity. A labeled thyroid hormone would be useful to track hormone metabolism through various pathways. While radiolabeled thyroid hormones have been synthesized and used for in vivo studies, a stable isotope labeled form of thyroid hormone is required for studying thyroid hormone metabolism by LC-MS/MS, an analytical technique that has certain advantages without the complications of radioactivity. Here we report the synthesis of 13C9- 15N-T2 and 13C9-15N- T4, two labeled thyroid hormone derivatives suitable for in vivo LC-MS/MS studies. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Hackenmueller, Sarah A.,Scanlan, Thomas S.
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p. 1439 - 1446
(2013/05/22)
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- Two modes of asymmetric polymerization of phenylacetylenes having an L -amino alcohol residue and two hydroxy groups
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Four novel chiral phenylacetylenes having an L-amino alcohol residue and two hydroxymethyl groups were synthesized and polymerized by an achiral catalyst ((nbd)Rh+[η6-(C6H5)B -(C6H5)3]) or a chiral catalytic system ([Rh(nbd)Cl]2/(S)- or (R)-phenylethylamine ((S)- or (R)-PEA)). The two resulting polymers having an L-valinol or L-phenylalaninol residue showed Cotton effects at wavelengths around 430 nm. This observation indicated that they had an excess of one-handed helical backbones. Positive and negative Cotton effects were observed only for the polymers having an L-valinol residue produced by using (R)- and (S)-PEA as a cocatalyst, respectively, although the monomer had the same chirality. Even when the achiral catalyst was used, the two resulting polymers having an L-valinol or L-phenylalaninol residue showed Cotton effects despite the long distance between the chiral groups and the main chain. We have found the first example of a new type of chiral monomer, that is, a chiral phenylacetylene monomer having an L-amino alcohol residue and two hydroxy groups that was suitable for both modes of asymmetric polymerization, that is, the helix-sense-selective polymerization (HSSP) with the chiral catalytic system and the asymmetric-induced polymerization (AIP) with the achiral catalyst. The other two monomers having L-alaninol and L-tyrosinol were found to be unsuitable to neither HSSP nor AIP because of their polymers' low solubility.
- Jia, Hongge,Li, Jun,Zang, Yu,Aoki, Toshiki,Teraguchi, Masahiro,Kaneko, Takashi
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p. 5134 - 5143
(2013/01/15)
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- The use of novel biodegradable, optically active and nanostructured poly(amide-ester-imide) as a polymer matrix for preparation of modified ZnO based bionanocomposites
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A novel biodegradable and nanostructured poly(amide-ester-imide) (PAEI) based on two different amino acids, was synthesized via direct polycondensation of biodegradable N,N′-bis[2-(methyl-3-(4-hydroxyphenyl)propanoate)] isophthaldiamide and N,N′-(pyromellitoyl)-bis-l-phenylalanine diacid. The resulting polymer was characterized by FT-IR, 1H NMR, specific rotation, elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) analysis. The synthesized polymer showed good thermal stability with nano and sphere structure. Then PAEI/ZnO bionanocomposites (BNCs) were fabricated via interaction of pure PAEI and ZnO nanoparticles. The surface of ZnO was modified with two different silane coupling agents. PAEI/ZnO BNCs were studied and characterized by FT-IR, XRD, UV/vis, FE-SEM and TEM. The TEM and FE-SEM results indicated that the nanoparticles were dispersed homogeneously in PAEI matrix on nanoscale. Furthermore the effect of ZnO nanoparticle on the thermal stability of the polymer was investigated with TGA and DSC technique.
- Abdolmaleki, Amir,Mallakpour, Shadpour,Borandeh, Sedigheh
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scheme or table
p. 1123 - 1129
(2012/06/15)
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- Synthesis and biological evaluation of tyrosine modified analogues of the α4β7 integrin inhibitor biotin-R8ERY
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The α4β7 integrin is a well-known target for the development of drugs against various inflammatory disease states including inflammatory bowel disease, type 1 diabetes and multiple sclerosis. The synthesis of a small library of cell-permeable β7 integrin inhibitors based on the peptide biotin-R8ERY is reported, in which the tyrosine residue has been modified by using the Suzuki-Miyaura cross-coupling reaction. The synthesised peptidomimetics were evaluated in a cell adhesion assay and shown to inhibit Mn2+-activated adhesion of mouse TK-1 T cells to mouse MAdCAM-1. All of the synthesised peptidomimetics are more active than our previously reported lead compound biotin-R8ERY with two of the analogues, 6 and 7, exhibiting IC50 values of 15 μM.
- Papst, Stefanie,Noisier, Anais F.M.,Brimble, Margaret A.,Yang, Yi,Krissansen, Geoffrey W.
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supporting information
p. 5139 - 5149
(2012/11/07)
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- METHODS AND SYSTEMS FOR PREPARING IRREVERSIBLE INHIBITORS OF PROTEIN TYROSINE PHOSPHATASES
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Described herein are the preparation and use of novel bromo- phosphonomethylphenylalanine amino acid derivatives (BrPmp) and BrPmp-containing peptides as specific, irreversible protein tyrosine phosphatase inhibitors, which are suitable for application in peptide synthesis. These derivatives are particularly advantageous since their synthesis is both easy and scalable, and they are suitable for peptide synthesis. The BrPmp derivatives described herein can be appropriately protected to allow for solid phase peptide synthesis (SPPS) and incorporation into peptides for preparation of protein tyrosine phosphatase inhibitors and inhibitor libraries. The peptides and peptide libraries can be used to identify new protein tyrosine phosphatase specific sequences and profile protein tyrosine phosphatase activity in cell lysates, diagnostic samples and biopsy samples.
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Page/Page column 19
(2011/10/03)
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- Synthesis, hydrolysis studies and phamacodynamic profiles of amide prodrugs of dexibuprofen with amino acids
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The present investigation deals with the synthesis of novel prodrugs of dexibuprofen with amino acids with an aim to achieve potent anti-inflammatory activity and less gastrointestinal toxicity. Structures of synthesized compounds were confirmed by spectral and elemental analyses. In vitro hydrolytic studies in simulated intestinal fluid, 80% plasma and rat faecal matter showed satisfactory release of dexibuprofen due to enzymatic cleavage. The synthesized prodrugs were evaluated for anti-inflammatory activity, analgesia, ulcerogenicity and histopathology. The anti-inflammatory activity of dexibuprofen was 43.3% whereas an improved value of 73.4, 77.3, 72.8 and 64.5% was observed for the synthesized prodrugs. The percentage analgesia of the prodrugs increased, whereas a decrease in the mean ulcer index values than dexibuprofen was observed. The histopathological studies revealed less ulceration in the gastric region when treated with prodrugs. Thus, the prodrugs were proved to be better in action as compared with the parent drug.
- Rasheed, Arun,Kumar, C. K. Ashok,Mishra, Ashutosh
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experimental part
p. 688 - 695
(2012/04/10)
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- Tyrosine-based poly(m-phenyleneethynylene-p-phenyleneethynylene)s. Helix folding and responsiveness to a base
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The Sonogashira-Hagihara polymerization of 3',5'-diiodo-N-α-tert-butoxycarbonyl-l-tyrosine methyl ester (1) and 3',5'-diiodo-N-α-tert-butoxycarbonyl-O-methyl-l-tyrosine methyl ester (2) with para-diethynylbenzene (3) was carried out to obtain optically active poly(m-phenyleneethynylene-p-phenyleneethynylene)s [poly(1) and poly(2)] with Mn's ranging from 9900 to 15,000 in 80-87% yields. Poly(1) exhibited intense CD signals in DMSO and THF, but did not in CH2Cl2, indicating that it took a predominantly one-handed helical conformation in the former two solvents. On the other hand, there was no evidence for poly(2) to take a helical structure in these solvents. Poly(1) turned the CD sign at 390 nm from plus to minus in DMSO/H2O = 9/1 (v/v) by the addition of NaOH. Alkaline hydrolysis of ester moieties of poly(1) and poly(2) gave the corresponding polymers having carboxy groups [poly(1a) and poly(2a)]. Poly(1a) and poly(2a) increased the CD intensity by the addition of NaOH.
- Liu, Ruiyuan,Sogawa, Hiromitsu,Shiotsuki, Masashi,Masuda, Toshio,Sanda, Fumio
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experimental part
p. 2255 - 2263
(2011/10/05)
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