- Novel chiral stationary phases based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin combining cinchona alkaloid moiety
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Novel chiral selectors based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5-dimethyl phenylcarbamoylated β-cyclodextrin (β-CD) chiral stationary phase (CSP) and 9-O-(tert-butylcarbamoyl)-QN-based CSP (QN-AX). Fmoc-protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD-based CSP and QN/QD-based CSPs have broader application range than β-CD-based CSP or QN/QD-based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc-amino acids accompanied by the synergistic effect of β-CD moiety, which lead to the different enantioseparation of β-CD-QN-based CSP and β-CD-QD-based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin-based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β-CD-based CSP for certain samples.
- Zhu, Lunan,Zhu, Junchen,Sun, Xiaotong,Wu, Yaling,Wang, Huiying,Cheng, Lingping,Shen, Jiawei,Ke, Yanxiong
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p. 1080 - 1090
(2020/05/25)
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- Repurposing the Pummerer Rearrangement: Determination of Methionine Sulfoxides in Peptides
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The reversible oxidation of methionine residues in proteins has emerged as a biologically important post-translational modification. However, detection and quantitation of methionine sulfoxide in proteins is difficult. Our aim is to develop a method for specifically derivatizing methionine sulfoxide residues. We report a Pummerer rearrangement of methionine sulfoxide treated sequentially with trimethylsilyl chloride and then 2-mercaptoimidazole or pyridine-2-thiol to produce a dithioacetal product. This derivative is stable to standard mass spectrometry conditions, and its formation identified oxidized methionine residues. The scope and requirements of dithioacetal formation are reported for methionine sulfoxide and model substrates. The reaction intermediates have been investigated by computational techniques and by 13C NMR spectroscopy. These provide evidence for an α-chlorinated intermediate. The derivatization allows for detection and quantitation of methionine sulfoxide in proteins by mass spectrometry and potentially by immunochemical methods.
- Woodroofe, Carolyn C.,Ivanic, Joseph,Monti, Sarah,Levine, Rodney L.,Swenson, Rolf E.
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p. 508 - 516
(2019/11/13)
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- Diethyl Selenodiglycolate: An Eco-Friendly Synthetic Antioxidant with Potential Application to Inflammatory Disorders
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This study describes a single step, high yield and purity, ecofriendly and scalable procedure to prepare a selenium derivative (diethyl selenodiglycolate). Diethyl selenodiglycolate rapidly reduces hypochlorous acid (HOCl, second-order rate constant of 7 × 107 M?1 s?1) to generate its corresponding selenoxide. In activated HL-60 cells, diethyl selenodiglycolate selectively reacted with HOCl (half maximal inhibitory concentration (IC50) = 23.07 μM) but not with superoxide anion radical or hydrogen peroxide without any cytotoxicity. These results show that this synthetically simple selenide reacts in a very efficient and specific way with the harmful pro-oxidant HOCl being a promising compound to be applied in oxidative inflammatory-related conditions.
- Archilha, Marcos V. L. R.,Giroldo, Lilian,Kuznetsov, Aleksey E.,Meotti, Flávia C.,Pinatto-Botelho, Marcos F.,da Silva, Railmara P.,dos Santos, Alcindo A.
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p. 1239 - 1248
(2020/10/14)
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- Determination of Chemical and Enantiomeric Purity of α-Amino Acids and their Methyl Esters as N-Fluorenylmethoxycarbonyl Derivatives Using Amylose-derived Chiral Stationary Phases
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Liquid chromatographic enantiomer separation and simultaneous determination of chemical and enantiomeric purity of α-amino acids and their methyl esters as N-fluorenylmethoxycarbonyl (FMOC) derivatives was performed on three covalently bonded type chiral stationary phases (CSPs) derived from amylose derivatives. The enantiomer separation of α-amino acid esters as N-FMOC derivatives was better than that of the corresponding acids, especially for CSP 1 and 2. Chemical impurities as the corresponding racemic acids present in several commercially available racemic amino acid methyl esters were observed to be 0.49–17.50%. Enantiomeric impurities of several commercially available L-amino acid methyl esters were found to be 0.03–0.58%, whereas chemical impurities as the corresponding racemic acids present in the same analytes were found to be 0.13–13.62%. This developed analytical method will be useful for the determination of chemical and enantiomeric purity of α-amino acids and/or esters as N-FMOC derivatives using amylose-derived CSPs.
- Islam, Md. Fokhrul,Adhikari, Suraj,Paik, Man-Jeong,Lee, Wonjae
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p. 332 - 338
(2019/04/13)
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- Preparation method of methionine derivative corrosion inhibitor
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The invention discloses a preparation method of a methionine derivative corrosion inhibitor. The method comprises the following steps: synthesis of Fmoc-methionine: adding methionine and Fmoc-OSu into a DMF (N,N-dimethylformamide) solvent to react, and adding NaHCO3 to remove the solvent and residual amine compounds, thereby obtaining the product, wherein the yield is 78%; synthesis of Fmoc-methionine acyl chloride: adding the Fmoc-methionine into 25ml of CH2Cl2, and refluxing to react for 4 hours; and synthesis of Fmoc-methionine amide: after the acyl-chlorination reaction, directly adding into an equal mole of octadecylamine CH2Cl2 solution to obtain a yellow solid, and purifying the product by a chromatographic column separation process, wherein the eluting solution is composed of dichloromethane and methanol in a volume ratio of 20:1. According to the preparation method, the Fmoc- protective group is connected to the methionine molecule by amidation, and the adsorption site formed by the pi-electron-containing benzene ring enhances the adsorptivity of the corrosion inhibitor molecule. The hydrophobic long chain is connected to the methionine molecule to resist the attack of water molecules, so that a protective film is formed on the steel surface, thereby achieving the goal of corrosion inhibition.
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Paragraph 0019; 0020
(2016/10/31)
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- Caged xanthones: Potent inhibitors of global predominant MRSA USA300
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Total of 22 caged xanthones were subjected to susceptibility testing of global epidemic MRSA USA300. Natural morellic acid showed the strongest potency (MIC of 12.5 μM). However, its potent toxicity diminishes MRSA therapeutic potential. We synthetically modified natural morellic acid to yield 13 derivatives (3a-3m). Synthetically modified 3b retained strong potency in MRSA growth inhibition, yet the toxicity was 20-fold less than natural morellic acid, permitting the possibility of using caged xanthones for MRSA therapeutic.
- Chaiyakunvat, Pongkorn,Anantachoke, Natthinee,Reutrakul, Vichai,Jiarpinitnun, Chutima
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supporting information
p. 2980 - 2983
(2016/06/13)
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- A mild method for the cleavage of the 4-picolyloxy group with magnesium under neutral conditions
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A mild and efficient method for the selective hydrolysis of 4-picolyl esters with magnesium in methanol or water in the presence of other esters and sensitive protecting groups is described. 4-Picolyl aryl ethers and thioethers are also smoothly deprotected to give the corresponding phenols and thiophenols. Georg Thieme Verlag Stuttgart. New York.
- Zhu, Jianwei,Miao, Wenjun,Bao, Lingling,Ji, Tao,Tang, Guo,Xu, Pengxiang,Zhao, Yufen
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supporting information; experimental part
p. 142 - 144
(2012/02/04)
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- Benzotriazole reagents for the syntheses of Fmoc-, Boc-, and Alloc-protected amino acids
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Stable Fmoc-, Boc-, and Alloc-benzotriazoles react with various amino acids including unprotected serine and glutamic acid, in the presence of triethylamine at 20° as reagents to introduce -amino protecting groups to afford Fmoc-, Boc-, and Alloc-protected amino acids (77-94%) free of dipeptide and tripeptide impurities. Fmoc-, and Alloc-Gly-Gly-OH dipeptides were prepared in 90% yields by N-acylation of glycylglycine with Fmoc- and Alloc-benzotriazoles in the presence of triethylamine. Synthesized N-protected amino acids were greater than 99% pure, analyzed by HPLC. Georg Thieme Verlag Stuttgart - New York.
- Ibrahim, Tarek S.,Tala, Srinivasa R.,El-Feky, Said A.,Abdel-Samii, Zakaria K.,Katritzky, Alan R.
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p. 2013 - 2016
(2011/10/08)
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- Liquid-chromatography quantitative analysis of 20 amino acids after derivatization with FMOC-CI and its application to different origin Radix isatidis
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We developed a simple, rapid and reliable method for determination of 20 common amino acids based on derivatization with 9-fluorenylmethyl chloroformate (FMOC-CI) and RP-LC/UV, this method was first introduced into quantitative analysis of amino acids. The amino groups of amino acids were trapped with FMOC-CI to form amino acid-FMOC-Cl adducts which can be suitable for LC-UV. Chromatographic separation was performed on a C18 column with a mobile phase gradient consisting of acetonitrile and sodium acetate solution. This method was shown to be sensitive for 20 common amino acids. In the intra-day precisions assay, the range of RSDs was 3.21-7.67% with accuracies of 92.34-102.51%; for the inter-day precisions assay, the range of RSDs was 5.82-9.19% with accuracies of 90.25-100.63%. The results also indicated that solutions of amino acids-FMOC-Cl can be kept at room temperature for at least 24 h without showing significant losses in the quantified values. The validated method was successfully applied to the determination of major four kinds of amino acids in R. isatidis samples (Arg, Pro, Met and Val). The total content of amino acids in different origin R. isatidis was 13.32-19.16 mg/g. The differences between R. isatidis samples were large using HCA.
- Zhou, Wei,Zhang, Xiao-Yan,Duan, Geng-Li
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experimental part
p. 509 - 515
(2012/01/04)
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- Efficient procedure for the preparation of oligomer-free N-fmoc amino acids
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A two-step method is presented for the peptide-free, high-purity, and high-yield synthesis of N-Fmoc amino acids. The first step involves the preparation of stable dicyclohexylammonium-amino acid ionic adduct in acetone. Subsequently, the ionic adducts, on reaction with Fmoc-Nosu under mild alkaline conditions, give dipeptide-free N-Fmoc amino acids. The positive charge of the dicyclohexylammonium counterion in the ionic salt has a longer radius, moderating the nucleophilicity of the carboxylate ion of the amino acid and preventing by-products by arresting the formation of mixed anhydrides, the precursors of oligopeptide impurities.
- Nowshuddin, Shaik,Rao,Reddy, A. Ram
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experimental part
p. 2022 - 2031
(2009/11/30)
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- A novel and efficient method for cleavage of phenacylesters by magnesium reduction with acetic acid
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(Equation Presented) In the present study, we use magnesium turnings as a new deprotection reagent for the phenacyl group during orthogonal organic synthesis in the presence of other esters and sensitive protecting groups. By applying the new magnesium turnings/acetic acid deprotection method, phenacyl group can be more easily combined with other protecting groups that are not compatible with the zinc/acetic acid method.
- Kokinaki, Stella,Leondiadis, Leondios,Ferderigos, Nikolas
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p. 1723 - 1724
(2007/10/03)
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- Antiangiogenic peptides
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Mammalian kringle 5 fragments and kringle 5 fusion proteins are disclosed as a compounds for treating angiogenic diseases. Methods and compositions for inhibiting angiogenic diseases are also disclosed.
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- GLP-2 compounds, formulations, and uses thereof
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The present invention relates to novel human glucagon-like peptide-2 (GLP-2) peptides and human glucagon-like peptide-2 derivatives which have a protracted profile of action as well as polynucleotide constructs encoding such peptides, vectors and host cells comprising and expressing the polynucleotide, pharmaceutical compositions, uses and methods of treatment.
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- Alternative and chemoselective deprotection of the α-amino and carboxy functions of N-Fmoc-amino acid and N-Fmoc-dipeptide methyl esters by modulation of the molar ratio in the AlCl3/N,N-dimethylaniline reagent system
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The amino and carboxy functions in N-Fmoc-α-amino acid and N-Fmoc-peptide methyl esters can be alternatively and chemoselectively deprotected by treatment with the reagent system AlCl3/N,N- dimethylaniline (DMA). The chemoselectivity of the process is controlled by modulating the relative molar ratio of the Lewis acid and DMA. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Di Gioia, Maria Luisa,Leggio, Antonella,Le Pera, Adolfo,Liguori, Angelo,Perri, Francesca,Siciliano, Carlo
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p. 4437 - 4441
(2007/10/03)
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- Apparatus and methods for detecting antibodies
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A single, unitary, solid phase support apparatus having a planar surface divided into a plurality of separate zone functions to detect antibodies. Each zone has bonded to it, a different peptide through its C-terminal end. The zones are incubated with the analyte sample and observed for reaction, indicating the virus-specific or bacteria specific presence or absence.
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- 9-Fluorenylmethyl Pentafluorophenyl Carbonate as a Useful Reagent for the Preparation of N-9-Fluorenylmethyloxycarbonylamino Acids and their Pentafluorophenyl Esters
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9-Fluorenylmethyl pentafluorophenyl carbonate is a useful reagent for the efficient, side reaction-free introduction of N-9-fluorenylmethyloxycarbonyl protecting group into amino acids and for the subsequent preparation of their pentafluorophenyl esters.Some new compounds of both types are described.
- Schoen, Istvan,Kisfaludy, Lajos
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p. 303 - 305
(2007/10/02)
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