- Novel thermo- and pH-responsive hydroxypropyl cellulose- and poly (l-glutamic acid)-based microgels for oral insulin controlled release
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Novel smart microgel particles made of poly (l-glutamic acid-2-hydroxylethyl methacrylate) (PGH) and hydroxypropyl cellulose-acrylic acid (HPC-AA) have been successfully prepared via emulsion polymerization. The dynamic light scattering measurement reveals that the average hydrodynamic radius 〈Rh〉 and hydrodynamic radius distributions f (R h) of the microgel particles depend on the temperature and pH value thus the microgel particles exhibit both pH- and temperature-sensitivity. In vitro release study shows that the amount of insulin released from microgels in the gastric juice (at pH 1.2) is significantly less than that in the intestinal fluid (at pH 6.8). These results indicate that the resultant microgels are of potential for use in intelligent oral drug delivery systems.
- Bai, Yunyan,Zhang, Zhe,Zhang, Aiping,Chen, Li,He, Chaoliang,Zhuang, Xiuli,Chen, Xuesi
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- The Synthesis of β-Benzyl L-Aspartate and γ-Benzyl L-Glutamate by Enzyme-Catalyzed Hydrolysis
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The enzyme-catalyzed hydrolysis of dibenzyl ester of aspartic acid and glutamic acid in α-position to give better yield of β-benzyl aspartate and γ-benzyl glutamate than the chemical method is reported.
- Chen, Shui-Tein,Wang, Kung-Tsung
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- BOROXAZOLIDONES AS SIMULTANEOUS PROTECTION OF THE AMINO AND CARBOXYL GROUP IN α-AMINO ACIDS
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The synthesis of boroxazolidones 1 from a variety of α-amino acids is given.These compounds 1 show a strong intramolecular coordination between B and the amino group.These heterocycles can serve as protected α-amino acids in which the α-amino and the carboxyl function are simultaneously blocked, while the side chain remains free for further reactions.The boroxazolidines were reconverted into α-amino acids under mild acid conditions.Using this methodology aspartic acid was converted into β-benzyl aspartate and glutamic acid into γ-benzyl glutamate.
- Nefkens, G. H. L.,Zwanenburg, B.
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- Cellular uptake and transfection activity of DNA complexes based on poly(ethylene glycol)-poly(l-glutamine) copolymer with PAMAM G2
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Poly(ethylene glycol)-poly(l-glutamine) (PEG-PLGA) copolymer EA-G2 (or EA-G1) was prepared by aminolysis of poly(ethylene glycol)-poly(l-benzyl glutamate) (PEG-PBLG) using PAMAM G2 (or G1). The chemical structure of PEG-PLGA was confirmed by FT-IR, 1H-NMR, DSC and GPC. The performances of the EA-G2 (or EA-G1) were assayed by enzyme degradation, MTT method and agarose gel electrophoresis. The particle size, zeta potential and morphology of EA-G2 (or EA-G1)/pDNA complexes were inspected by DLS and AFM. The cellular uptake mechanism was evaluated by endocytic inhibiting test, cell uptake test and observation of CLSM. The transfection activity was measured by flow cytometry. The EA-G2 (or EA-G1) exhibited good biodegradability, low cytotoxicity and great ability to combine with pDNA. The EA-G2 (or EA-G1) complexes exhibited particle sizes in the range 120-180 nm and zeta potentials in the range 20-40 mV, which were suitable for cell uptake. The cellular uptake of the EA-G2 complexes occurred mainly through clathrin-dependent and caveolin-mediated endocytosis, and at 6 h in 10% FBS and in serum-free media, the percentages of complex uptake reached 89.0% or 72.7%, respectively. EA-G2 complexes could efficiently mediate pEGFP-Cl into the cell nuclei. EA-G2 complexes displayed enhancing transfection efficiency and better serum tolerance. The results suggest that the EA-G2 has potential to be used as a biodegradable, efficient and serum-resistant gene vector.
- Pan, Shirong,Cao, Duanwen,Fang, Rong,Yi, Wu,Huang, Huan,Tian, Shouqin,Feng, Min
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- Synthesis and self-assembly of thermoresponsive amphiphilic biodegradable polypeptide/poly(ethyl ethylene phosphate) block copolymers
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We report the design and synthesis of new fully biodegradable thermoresponsive amphiphilic poly(γ-benzyl L-glutamate)/poly(ethyl ethylene phosphate) (PBLG-b-PEEP) block copolymers by ring-opening polymerization of N-carboxy-γ-benzyl L-glutamate anhydride (BLG-NCA) with amine-terminated poly(ethyl ethylene phosphate) (H2N-PEEP) as a macroinitiator. The fluorescence technique demonstrated that the block copolymers could form micelles composed of a hydrophobic core and a hydrophilic shell in aqueous solution. The morphology of the micelles as determined by transmission electron microscopy (TEM) was spherical. The size and critical micelle concentration (CMC) values of the micelles showed a decreasing trend as the PBLG segment increased. However, UV/Vis measurements showed that these block copolymers exhibited a reproducible temperature-responsive behavior with a lower critical solution temperature (LCST) that could be tuned by the block composition and the concentration.
- Wu, Qiuhua,Zhou, Dan,Kang, Renyu,Tang, Xiuping,Yang, Qi,Song, Ximing,Zhang, Guolin
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- Orientational properties of poly-γ-benzyl-L-glutamate: Influence of molecular weight and solvent on order parameters of the solute
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Residual dipolar couplings (RDCs) have recently become increasingly important in organic structure determination due to their unique information content. One main limitation for the use of RDCs in organic compounds, however, is that the compound in question needs to be oriented with respect to the magnetic field in order to measure RDCs. So far, there are very few possibilities for modulating the induced degree of orientation. The situation is even worse when chiral orienting media are considered, which could allow absolute configuration determination in the future. We have conducted a systematic investigation into modulating the orientation induced by one chiral orienting medium, namely organic solutions of PBLG (poly-γ-benzyl-L- glutamate), as a function of its molecular weight and the organic co-solvent used, and have obtained significant insights into factors that influence the order induced. With increasing molecular weight of the polypeptide the orientation of the solutes decreases, leading to well-resolved spectra with improved line shapes. This can be attributed exclusively to the fact that the critical concentration of the liquid-crystalline phase decreases with increasing molecular weight (pure dilution effect). Any influence of increasing flexibility on the orientation can be ruled out.
- Marx, Andreas,Thiele, Christina
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- Highly stable polyglutamate derivatives/siRNA polyplex efficiently down-relegate survivin expression and augment the efficacy of cisplatin
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RNA interfere (RNAi)-based technology holds great promise in cancer treatment. The use of small interfering RNA (siRNA), however, is hampered by its low delivery efficiency in vivo when they are diluted in blood biofluids and in the presence of serum and salt. In this study, we developed the polyglutamate derivative polymer brush, poly(ethyleneglycol) monomethyl ether-b-polyglutamate-g-spermine (mPEG-b-PG-g-spermine, PPGS), which could efficiently deliver survivin-siRNA under ultra-high dilution and in the presence of salt (NaCl 150 mM) and serum (10% FBS), most likely due to its PEG-shelled polymer brush structure. On the contrary, aggregation occurred when PEI/siRNA polyplex dispersed in saline and serum-containing media and PEI polyplex dissociated after making a 256-fold dilution. PPGS/si-survivin polyplex exhibited high cellular uptake efficiency and efficiently down-regulated the expression of survivin mRNA in the cisplatin-resistance of non-small cell human lung adenocarcinoma (A549/DDP) cells in the presence of serum. However, either PEI polyplex or Lipofectmine 2000 complex was unstable in serum and salt-containing media and at high dilution rates, which resulted in their dramatical decrease of cellular uptake and gene-silencing efficiency in these conditions. The PPGS/si-survivin polyplex also exhibited synergistic effects of killing the cancer cells by combination treatment with cisplatin. Therefore, the PPGS gene carrier showed great potential in systemic siRNA delivery, and its combination with chemotherapeutic drug is promising in treating drug resistant cancers.
- Wang, Zhongjuan,Zou, Haijuan,Wang, Zirui,Wu, Jiamin,Xia, Zhongsheng,Feng, Min
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- Microwave assisted synthesis and antimicrobial study of Schiff base vanadium(IV) complexes of phenyl esters of amino acids
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Schiff base vanadium(IV) complexes of phenyl esters of the two acidic amino acids, i.e., aspartic and glutamic acid, were synthesized. The phenyl esters of these amino acids were synthesized by conventional method whereas the Schiff base vanadium(IV) complexes were synthesized using microwave irradiation. The complexes were characterized by spectroscopic tools such as IR, 1H NMR, mass (ES), ESR, and UV visible spectroscopy. All the complexes were studied for antibacterial and antifungal activity and found to be moderately active. Copyright Taylor & Francis Group, LLC.
- Wazalwar, Sachin S.,Bhave, Narayan S.,Dikundwar, Amol G.,Ali, Parvez
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Read Online
- Design, synthesis, and biological evaluation of desmuramyl dipeptides modified by adamantyl-1,2,3-triazole
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Muramyl dipeptide (MDP) is the smallest peptidoglycan fragment able to trigger the immune response. Structural modification of MDP can lead to the preparation of analogs with improved immunostimulant properties, including desmuramyl peptides (DMPs). The aim of this work was to prepare the desmuramyl peptide (L-Ala-D-Glu)-containing adamantyl-triazole moiety and its mannosylated derivative in order to study their immunomodulatory activities in vivo. The adjuvant activity of the prepared compounds was evaluated in a murine model using ovalbumin as an antigen, and compared to the reference adjuvant ManAdDMP. The results showed that the introduction of the lipophilic adamantyl-triazole moiety at the C-terminus of L-Ala-D-Glu contributes to the immunostimulant activity of DMP, and that mannosylation of DMP modified with adamantyl-triazole causes the amplification of its immunostimulant activity.
- ?kalamera, Dani,Antica, Mariastefania,Car, ?eljka,Dra?enovi?, Josip,Milkovi?, Lidija,Perokovi?, Vesna Petrovi?,Ribi?, Rosana,Stojkovi?, Ranko,Tomi?, Sr?anka
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supporting information
(2021/11/01)
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- Preparation method of N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid
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The invention provides a preparation method of N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid. The preparation method mainly solves the technical problems of complexity, long period, high cost, and low yield of an original process, and comprises the following steps: (1) preparing N-fluorenylmethoxycarbonyl-L-glutamic acid; (2) preparing N-fluorenylmethoxycarbonyl-L-glutamic acid-1-benzyl ester; (3) preparing S-triphenylmethyl cysteamine; (4) preparing N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid-alpha-benzyl ester; and (5) preparing N-fluorenylmethoxycarbonyl-gamma-(S-triphenylmethyl-cysteamine)-L-glutamic acid. The method is rapid, high in yield and simple in separation and purification, and the used solvent is environment-friendly and is suitable for mass production.
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Paragraph 0061
(2020/10/05)
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- Rhamnolipid inspired lipopeptides effective in preventing adhesion and biofilm formation of Candida albicans
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Rhamnolipids are biodegradable low toxic biosurfactants which exert antimicrobial and anti-biofilm properties. They have attracted much attention recently due to potential applications in areas of bioremediation, therapeutics, cosmetics and agriculture, however, the full potential of these versatile molecules is yet to be explored. Based on the facts that many naturally occurring lipopeptides are potent antimicrobials, our study aimed to explore the potential of replacing rhamnose in rhamnolipids with amino acids thus creating lipopeptides that would mimic or enhance properties of the parent molecule. This would allow not only for more economical and greener production but also, due to the availability of structurally different amino acids, facile manipulation of physico-chemical and biological properties. Our synthetic efforts produced a library of 43 lipopeptides revealing biologically more potent molecules. The structural changes significantly increased, in particular, anti-biofilm properties against Candida albicans, although surface activity of the parent molecule was almost completely abolished. Our findings show that the most active compounds are leucine derivatives of 3-hydroxy acids containing benzylic ester functionality. The SAR study demonstrated a further increase in activity with aliphatic chain elongation. The most promising lipopeptides 15, 23 and 36 at 12.5 μg/mL concentration allowed only 14.3%, 5.1% and 11.2% of biofilm formation, respectively after 24 h. These compounds inhibit biofilm formation by preventing adhesion of C. albicans to abiotic and biotic surfaces.
- Jovanovic, Milos,Radivojevic, Jelena,O'Connor, Kevin,Blagojevic, Stevan,Begovic, Biljana,Lukic, Vera,Nikodinovic-Runic, Jasmina,Savic, Vladimir
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supporting information
p. 209 - 217
(2019/03/23)
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- SPIRO-LACTAM NMDA RECEPTOR MODULATORS AND USES THEREOF
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Disclosed are compounds having potency in the modulation of NMDA receptor activity. Such compounds can be used in the treatment of conditions such as depression and related disorders as well as other disorders.
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Page/Page column 36
(2019/08/26)
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- DIPEPTIDE MIMETICS OF NGF AND BDNF NEUROTROPHINS
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The invention relates to compounds having either agonist or antagonist activities for the neurotrophins NGF and BDNF and represented by monomeric or dimeric substituted dipeptides that are analogs of the exposed portions of loop 1 or loop 4 regions of these neurotrophins near or at a beta-turn of the respective loop. N-acylated substituents of these dipeptides are biostereoisomers of the amino acid residues preceding these dipeptide sequences in the neurotrophin primary structure. The dimeric structure is produced advantageously by using hexatnethylenediaanine to which dipeptides are attached via their carboxyl groups. The claimed compounds displayed neuroprotective and differentiation-inducing activities in cellular models and enhanced the amount of phosphorylated tyrosine kinase A and the heat shock proteins Hsp32 and Hsp70 in the concentration range of 10 -9 to 10 -5 M. They also displayed neuroprotective, anti-parkinsonian, anti-stroke, anti-ischemic, anti-depressant and anti-amnestic activities in animal models and were active in experimental models of Alzheimer's disease. These in vivo effects of the claimed compounds are displayed in the dose range of 0.01 to 10 mg/kg when administered intraperitoneally.
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Paragraph 0077
(2019/04/16)
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- A method for preparation of hybrid amphiphilic star copolymer nano micelles
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Hybrid amphiphilic star copolymer nano micelles are prepared in the invention. Cage shaped octa(γ-aminopropyl) silsesquioxanes is selected as the inorganic part, and L-glutamic benzyl ester-five membered ring anhydride is ring-opening polymerized by the initiation of amino groups on the surface of cage shaped octa(γ-aminopropyl) silsesquioxanes, producing copolymers with cage shaped octa(γ-aminopropyl) silsesquioxanes as nucleus and poly (L-glutamic-benzyl ester) as arms. The copolymers reacts with monomethoxy poly (ethylene glycol) carboxylic acid by condensation. Finally, the benzyl groups in the side chains of poly (L-glutamic acid-benzyl ester) are converted into hydrazine groups by acylhydrazination to obtain hybrid amphiphilic star copolymer nano micelles. The micelles can load doxorubicin, they are safe to human body and have good application prospects.
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Paragraph 0029
(2019/04/30)
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- NOVEL MURAMYL PEPTIDE DERIVATIVE COMPOUND, SYNTHESIS AND USES THEREOF
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The invention relates to novel Muramyl Dipeptide (MDP) derivative compound of structural Formula-VIII, a process for synthesis, intermediates used in the synthesis and use thereof; wherein R1 and R2 both are hydrogen; or R1 is hydrogen and R2 is alkyl or aryl; or R1 is alkyl or aryl and R2 is hydrogen; or R1 and R2 both are alkyl or aryl (same or different groups); wherein alkyl group constitute C1-C6 alkyl or higher (both linear and branched) with or without heteroatoms; and aryl group constitute phenyl, substituted phenyl, heteraryl, arylalkyl and polynuclear aromatics. These compounds possess excellent pharmacological properties, in particular immunomodulating properties for use as adjuvant in vaccine formulations. These compounds are, particularly useful as adjuvants in vaccines.
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Paragraph 0163; 0165
(2019/01/04)
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- NOVEL MURAMYL PEPTIDE DERIVATIVE COMPOUND, SYNTHESIS AND USES THEREOF
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The invention relates to novel Muramyl Dipeptide (MDP) derivative compound of structural Formula-VIII, a process for synthesis, intermediates used in the synthesis and use thereof. R = alkyl (both linear and branched), aryl, substituted aryl, alkoxy alkyl Wherein, R can be both linear and branched alkyl, aryl, substituted aryl and alkoxy alkyl. These compounds possess excellent pharmacological properties, in particular immunomodulating properties for use as adjuvant in vaccine formulations. These compounds are, particularly useful as adjuvants in vaccines.
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Page/Page column 18; 32
(2017/06/30)
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- CHEMICAL SYNTHESIS AND ANTI-TUMOR AND ANTI-METASTATIC EFFECTS OF DUAL FUNCTIONAL CONJUGATE
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The present invention discloses chemical synthesis, anti-tumor and anti-metastatic effects of a dual functional conjugate as showed by formula I. In detail, paclitaxel or docetaxol is linked with muramyl dipeptide derivative to form a conjugate, thus dual anti-tumor and anti-metastatic effects are achieved by combination of chemotherapy and immunotherapy. The present invention also discloses that paclitaxel or docetaxol and muramyl dipeptide derivative conjugate is synthesized by combination of solid-phase and solution-phase synthesis, and said conjugate can be used in manufacture of anti-tumor medicaments as proved by reliable bioassays.
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Paragraph 0119; 0120; 0121-0122
(2017/10/24)
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- Tetrapeptide Copper Catalysts Capable Of Oxidizing Hydrocarbons At Room Temperature
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The present invention relates to peptide copper catalysts capable of oxidizing hydrocarbons at room temperature.
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Paragraph 0163
(2016/08/03)
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- Preparation method of glutamic acid-5-benzyl ester-1-tert-butyl ester hydrochloride
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A preparation method of glutamic acid-5-benzyl ester-1-tert-butyl ester hydrochloride mainly solves the problem of operation difficulty in the synthesis method of the prior arts. A technical scheme is as below: the preparation method of glutamic acid-5-benzyl ester-1-tert-butyl ester hydrochloride comprises the steps of: esterifying a starting material of glutamic acid with benzyl alcohol, and purifying to obtain glutamic acid 5-benzyl ester; conducting a transesterification reaction on glutamic acid 5-benzyl ester and tert-butyl acetate under catalysis to obtain glutamic acid-5-benzyl ester-1-tert-butyl ether; and finally controlling the atmosphere with ether hydrochloric acid to an acidic state to obtain the glutamate 5-benzyl-1-t-butyl ester hydrochloride. The product can be used for the field of peptide synthesis.
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Paragraph 0014
(2016/11/24)
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- Chemical synthesis and anti-tumor and anti-metastatic effects of dual functional conjugate
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The present invention discloses chemical synthesis, anti-tumor and anti-metastatic effects of a dual functional conjugate as shown by formula I. Specifically, paclitaxel or docetaxol is linked with muramyl dipeptide derivative to form a conjugate, thus dual anti-tumor and anti-metastatic effects are achieved by combination of chemotherapy and immunotherapy. The present invention also discloses that paclitaxel or docetaxol and muramyl dipeptide derivative conjugate is synthesized by combination of solid-phase and solution-phase synthesis, and said conjugate can be used in manufacture of anti-tumor medicaments as proved by reliable bioassays.
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(2015/07/27)
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- High selective autocatalytic esterification of glutamic acid by benzyl alcohol with CuCl2 promoting
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We found that the esterification of l-glutamic acid by benzyl alcohol is greatly promoted by CuCl2 even in H2O solvent, and the selectivity and yield of γ-benzyl ester of l-glutamic acid achieved 100% and 95.31%. Metal cation coordin
- Ma, Yinggai,Li, Zhenhuan,Su, Kunmei,Cheng, Bowen
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- Synthesis and characterization of ultrathin metal coordination Prussian blue nanoribbons
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Ultrathin metal coordination Prussian blue (PB) nanoribbons with tunable width have been successfully synthesized. The morphology and microstructure of PB nanoribbons are characterized using UV-vis, FT-IR, AFM, TEM and XRD. PB nanoribbons synthesized possess an ultrathin thickness of approximately 1 nm and narrow width. The width of PB ribbons can be tuned by varying the chain length of polymeric precursors. The PB hybrid nanoribbons synthesized exhibit enhanced thermal stability and electrochemical activity. The merit of narrow and tunable width as well as ultrathin thickness of PB hybrid nanoribbons along with enhanced thermal stability and electrochemical activity makes them potentially useful in nano-devices, biosensors and so on.
- Bao, Suping,Qin, Wangping,Wu, Qihua,Liang, Guodong,Zhu, Fangming,Wu, Qing
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p. 5242 - 5246
(2013/05/21)
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- Solution-phase synthesis of a muramyl dipeptide analogue MDA
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The solution-phase synthesis of a muramyl dipeptide (MDP) analogue of Nα-[4-chlorocinnamoyl-l-alanyl-d-isoglutaminyl]-l-lysine (MDA, 2) is reported that possesses the features of easy feasibility, safety and low cost in large scale of synthesis.
- Zhao, Nan,Ma, Yao,Liu, Gang
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scheme or table
p. 1443 - 1446
(2012/06/04)
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- A new phenylethyl alkyl amide from the Ambrostoma quadriimpressum Motschulsky
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A new phenylethyl alkyl amide, (10R)-10-hydroxy-N-phenethyloctadecanamide (1), was isolated from the beetle Ambrostoma quadriimpressum Motschulsky. The structure of the amide was determined by NMR and MS. The absolute configuration of compound 1 was confirmed by an asymmetric total synthesis, which was started from L-glutamic acid. The construction of the aliphatic chain was accomplished by the selective protection of the hydroxy groups and two-time implementation of the Wittig olefination reaction.
- Zhao, Guolei,Yang, Chao,Li, Bing,Xia, Wujiong
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supporting information; experimental part
p. 1342 - 1346
(2011/11/14)
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- Asymmetric michael addition of malonates to enones catalyzed by a primary Β-amino acid and its lithium salt
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Highly enantioselective Michael addition of malonates to enones was achieved using a mixed catalyst consisting of a primary Β-amino acid, O-TBDPS (S)-Β-homoserine, and its lithium salt. Various cyclic and acyclic enones were converted into 1,5-ketoesters in high yields (up to 92%) with high enantioselectivity (up to 97% ee) under mild reaction conditions. Details of synthesis of the catalyst, optimization of the reaction conditions for the Michael addition reaction, and a plausible reaction mechanism are described.
- Yoshida, Masanori,Narita, Mao,Hara, Shoji
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experimental part
p. 8513 - 8517
(2011/12/03)
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- Organo-catalyzed ring opening polymerization of a 1,4-dioxane-2,5-dione deriving from glutamic acid
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The (3S)-[(benzyloxycarbonyl)ethyl]-1,4-dioxan-2,5-dione (BED) was prepared in four steps starting from glutamic acid and bromoacetyl bromide. According to X-ray diffraction analysis, the pendant functional group is located in equatorial position and points away from the six-membered ring. The organo-catalyzed ring-opening polymerization of BED was promoted with 4-dimethylaminopyridine (DMAP) and the combination of thiourea TUCy and (-)-sparteine. PolyBED samples of number-average molar mass Mn up to 36000 and narrow polydispersity (Mw/Mn 1H-13C HMBC 2D NMR experiment. The preparation of 1:1 adducts with n-pentanol confirmed that ring-opening of BED occurs almost indifferently on either of the endocyclic ester groups. Poly(α-hydroxyacids) featuring pendant carboxylic acids were finally obtained by acetylation of the terminal OH groups followed by hydrogenolysis.
- Du Boullay, Olivier Thillaye,Saffon, Nathalie,Diehl, Jean-Pierre,Martin-Vaca, Blanca,Bourissou, Didier
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experimental part
p. 1921 - 1929
(2011/04/17)
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- Design and synthesis of all diastereomers of cyclic pseudo-dipeptides as mimics of cyclic CXCR4 pentapeptide antagonists
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The four diastereomers of 2,5-bis[(3-guanidino)propyl]-1-[3-(4- hydroxyphenyl)propionyl]-7-(2-naphthylacetyl)-1,4,7-triazacycloundec-9-en-3-one (54-57) and of 2,5-bis[(3-guanidino)propyl]-1-(4-hydroxyphenylacetyl)-7-(2- naphthylacetyl)-1,4,7-triazacycloundec-9-en-3-one (58-61) were synthesized by a divergent methodology from l- and d-glutamic acids. The 11-membered ring core was made by ring closing metathesis of linear bis(allylamines), and the guanidyl functions were introduced by a simultaneous double Mitsunobu reaction using bis(Boc)guanidine. These compounds were designed to mimic cyclic pentapeptide FC131 (c[Gly-d-Tyr-Arg-Arg-Nal]). The Royal Society of Chemistry.
- Cluzeau, Jerome,Oishi, Shinya,Ohno, Hiroaki,Wang, Zixuan,Evans, Barry,Peiper, Stephen C.,Fujii, Nobutaka
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p. 1915 - 1923
(2008/02/10)
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- Decomposition of copper-amino acid complexes by sodium sulfide
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Sodium sulfide very efficiently removes copper from protected amino acid-copper complexes. The copper in the amino acid complex was reduced to insoluble cuprous sulfide and the free amino acid was released in pure form. This method is very convenient and rapid, requiring only 5-10 min and 0.55-0.75 equiv of sodium sulfide.
- Nowshuddin, Shaik,Reddy, A. Ram
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p. 5159 - 5161
(2007/10/03)
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- Process for the preparation of omega-benzyl esters of amino diacids and of alkanesulphonates of these esters, and these alkanesulphonates
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The invention relates to a process for the preparation of an ?-benzyl ester of an amino diacid, characterized in that the amino diacid is reacted with a benzyl alcohol derivative of formula (I) 1 in which the R1 substituent or substituents, which are identical or different, represent a hydrogen atom, a C1 to C4 alkyl group, a C1 to C4 alkoxy group or a halogen atom and n is equal to 1, 2 or 3, in the presence of at least one mol per mole of the amino diacid of an alkanesulphonic acid, optionally in the presence of a solvent. The intermediate alkanesulphonates of the ?-benzyl esters of amino diacids and the ?-benzyl esters of amino diacids are obtained with a good yield and an excellent purity by virtue of this process.
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- Solid-phase synthesis of muramyl dipeptide (MDP) derivatives using a multipin method
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Solid-phase synthetic method of muramyl dipeptide derivatives is reported. A diverse library of muramyl dipeptides could be potentially synthesized by acylation, reductive alkylation, sulfonamide formation, urea formation, N-alkylation, amine addition, or component Ugi reactions based on this method for drug screening. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Liu, Gang,Zhang, Shuo-De,Xia, Shu-Quan,Ding, Zhen-Kai
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p. 1361 - 1363
(2007/10/03)
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- Synthesis of a radoilabeled type A cholecystokinin receptor antagonist, (R)-N-pentyl-N-(4,5-di[3H]pentyl)N(α)-(3-quinolinoyl)glutamic acid amide
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A method for the preparation of a radiolabeled CCK(A)-specific antagonist, (R)-N-pentyl-N-(4,5-di[3H]pentyl)N(α)-(3-quinolinoyl)glutamic acid amide, [3H]-A-65186, is described. (R)-γ-Benzyl-N-BOC-glutamic acid was coupled with N-(4-pentenyl)-N-pentylamine using BOPCl and TEA in dichloromethane to provide the corresponding amide. Deprotection of the α-amino moiety followed by coupling with 3-quinolinecarboxylic acid in the presence of EDCI, TEA, and HOBt in dichloromethane resulted in (R)-N-(4-pentenyl)-N-pentyl γ-benzyl-N(α)-(3-quinolinoyl)glutamic acid amide. Tritiation with concomitant hydrogenolysis of the benzyl ester proceeds smoothly to provide [3H]-A-65186.
- Malone, Justin A.,Reidelberger, Roger D.,Hulce, Martin
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- The synthesis of pyrimidin-4-yI substituted a-amino acids. a versatile approach from alkynyl ketones
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The reaction of amidines with a-amino acid alkynyl ketones is shown to be a versatile route to pyrimidin-4-yl substituted a-amino acids. This route is also applicable to a parallel synthesis approach and has allowed the formation of a range of pyrimidin-4-yl substituted a-amino acids, including the naturally occurring a-amino acid L-lathyrine 4.
- Adlington, Robert M.,Baldwin, Jack E.,Catterick, David,Pritchard, Garcth J.
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p. 855 - 866
(2007/10/03)
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- Synthesis of the Enantiomeric Furobenzofurans, Late Precursors for the Synthesis of (+)- and (-)-Aflatoxins B1, B2, G1, and G2
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Enantiomeric tetrahydrofurobenzofurans, representing the ABC tricyclic portion of aflatoxins B1, B2, G1, and G2, were generated from the oxaza-Cope rearrangement of a suitably functionalized O-aryloxime.The O-aryloxime was, in turn, made from the condensation of an enantiomerically pure aldehyde derived from glutamic acid and a substituted phenoxyamine.High regioselectivity with respect to the A-ring substituents of the ABC tricycle was achieved through the use of electrochemistry.The regioselective electrochemical cleavage of 4,6-bis(tosyloxy)-2-(methoxycarbonyl)- 2,3,3a,8a-tetrahydrofurobenzofuran (22) resulted in a 97/3 mixture of regioisomeric phenols.The regiochemical assignments of the resulting phenols were determined by 2D NOESY NMR.The enantiomeric ratio of the final product was determined to be 96/4 by NMR analysis of diastereomers resulting from the coupling of 31a to (+)- and (+/-)-phenethylamine.
- Civitello, Edgar R.,Rapoport, Henry
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p. 3775 - 3782
(2007/10/02)
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- Acceleration of the N(α)-deprotection rate by the addition of m-cresol to diluted methanesulfonic acid and its application to the Z(OMe)-based solid-phase syntheses of human pancreastatin-29 and magainin 1
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In solid-phase peptide synthesis, the addition of m-cresol to diluted methanesulfonic acid (MSA) in dichloromethane accelerated the deprotection rate of the acid-labile α-amino protecting group, the p-methoxybenzyloxycarbonyl (Z(OMe)) group. Further, 0.1 M MSA, 20% m-cresol/CH2Cl2 was found to be a practically useful N(α)-deprotecting reagent system, since the deprotection of the Z(OMe) group occurred selectively within 30 min at room temperature, leaving intact the other side chain protecting groups, such as benzyloxycarbonyl, benzyl ester, S-p-methoxybenzyl and N(G)-mesitylene-2-sulfonyl groups. This reagent system was applied to the Z(OMe)-based solid phase syntheses of human pancreastatin-29 and magainin 1.
- Tamamura,Nakamura,Noguchi,Funakoshi,Fujii
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p. 954 - 957
(2007/10/02)
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- Liquid Crystallinity in para-Substituted Poly γ-benzyl-L-glutamates
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The liquid crystalline behavior of poly γ-p-fluorobenzyl-L-glutamate, poly γ-p-trifluoromethylbenzyl-L-glutamate, poly γ-p-nitrobenzyl-L-glutamate, and poly γ-benzyl-L-glutamate has been investigated.The first two polymers are new materials while the synthesis of the latter two has been reported in the literature.Only the liquid crystalline properties of poly γ-benzyl-L-glutamate have been previously reported and this study was initiated in order to determine if electron withdrawing substituents in the para position would influence the liquid crystal behavior of these polymers.Poly γ-benzyl-L-glutamate was used as the reference standard to which the other three were compared.Under the experimental conditions employed, the equispacings for poly γ-benzyl-L-glutamate were 4-6 μm, poly γ-p-fluorobenzyl-L-glutamate, 6-8 μm, poly γ-p-trifluoromethylbenzyl-L-glutamate, 7-9 μm, and poly γ-p-nitrobenzyl-L-glutamate, 11-15 μm.The equispacings for the para nitro polymer show the largest difference from the unsubstituted benzyl ester polymer, with approximately twice the value than that for poly γ-benzyl-L-glutamate.The results of this study have shown that, in the poly glutamic acid benzyl ester system, the presence of a strong electron withdrawing group in the para position of the benzyl function does influence the liquid crystal properties of this polymer system. - Keywords: para-substituted poly-γ-benzyl-L-glutamates, -NO2, F, -CF3 liquid crystallinity, interspacings
- Choi, Dong-Hoon,Zand, Robert
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- Enzymatic Synthesis of Side Chain Benzyl Esters of L-α-Amino Dicarboxylic Acids
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Diesters of L-α-amino dicarboxylic acids were specifically hydrolyzed by pronase at their α carboxylic group while the corresponding D-enantiomers remained unchanged.This enabled easy obtention of side chain benzyl esters of L-α-amino dicarboxylic acids starting from both optically active and racemic dibenzyl ester derivatives. Key Words: Enzymatic Synthesis: Pronase: L-α-amino suberic acid-ω-benzyl ester; Regioselectivity; Optical Resolution.
- Pugniere, Martine,Castro, Bertrand,Domergue, Nicole,Previero, Aldo
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p. 1015 - 1018
(2007/10/02)
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- The Chiral Synthesis of Thiazole Amino Acid Enantiomers
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An efficient modified Hantzsch reaction is described for the synthesis of optically pure thiazole amino acid derivatives from the corresponding amino acids.The method is exemplified by the synthesis of a derivative of L-(Gln)Thz, the novel chiral thiazole amino acid moiety of dolastatin 3.The Cotton effects of thiazole amino acids correlate well with the absolute stereochemistry of these compounds.
- Bredenkamp, Martin W.,Holzapfel, Cedric W.,Zyl, Wynand J. van
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p. 2235 - 2249
(2007/10/02)
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- NMR-Spectroscopic Assignment of the Aib-Methyl Groups in α-Helical and β-Turn Environment with the Use of Selectively Deuterated Aib. The Solution Conformations of Boc-Ala-Aib-Ala-OMe
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Boc-Ala-Aib-Ala-OMe (1a) adopts in the crystal a conformation similar to a β-turn type II.From 13C-CP-MAS spectra the magnetic nonequivalence of the Aib-Cβ atoms amounts to 6.1 ppm.The pro-S-Cβ carbon signal is shifted upfield as can be shown by comparison with the spectra of Boc-Ala-(R)-Aib-Ala-OMe (1b).This assignment corresponds to a downfield shift of the Aib pro-S-Cβ carbon in the helix of Boc-4-Aib-7-O-PEG-M (2a), where it was established with the aid of the (R)-Aib-containing analog (2b).From molecular dynamics simulations of Boc-Ala-Aib-Ala-OMe we propose two major conformational species in solution that account for the observed MNE of 2.1 ppm, the temperature gradients of the amide protons, the coupling constants, and the distances derived from ROESY spectra.
- Leibfritz, Dieter,Brunne, Roger M.,Weihrauch, Thomas,Stelten, Johannes,Haupt, Erhard T.K.,Stohrer, Wolf-Dieter
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p. 1017 - 1028
(2007/10/02)
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- New Reagents to Decompose Copper Complexes of Amino Acids
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The use of N,N-dialkyl-N'-(benzoyl)thioureas in ethanol is an effective method to decompose copper complexes of amino acids.The reaction gives optimal yields, and no racemisation is observed.Furthermore, the recovery of the thiourea derivatives is an important advantage of this method.
- Koenig, Karl-Heinz,Kaul, Lothar,Kuge, Martin,Schuster, Michael
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p. 1115 - 1116
(2007/10/02)
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- A Simple and Convenient Synthesis of β-Aspartates and γ-Glutamates
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A simple and convenient, high yield synthesis of ω-esters of aspartic as well as glutamic acid has been developed, using tetrafluoroboric acid as catalyst. (13)C-NMR data of the products are given.
- Albert, Rainer,Danklmaier, Johann,Hoenig, Helmut,Kandolf, Harald
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p. 635 - 637
(2007/10/02)
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- Novel immunological adjuvant compounds and methods of preparation thereof
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This application relates to novel immunological adjuvant compounds of the formula: STR1 wherein each of R and R1 are the same or different and are hydrogen or an acyl radical; R2 is an unsubstituted or substituted alkyl radical, or an unsubstituted or substituted aryl radical; R6 is an alkyl radical X is an aminoacyl moiety; and Y is D-isoasparagine or D-isoglutamine.
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- Novel immunological adjuvant compounds and methods of preparation thereof
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This application relates to novel immunological adjuvant compounds of the formula: STR1 wherein each of R and R1 are the same or different and are hydrogen or an acyl radical; R2 is an unsubstituted or substituted alkyl radical, or an unsubstituted or substituted aryl radical; X is an aminoacyl moiety; and Y is D-isoasparagine or D-isoglutamine.
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