- Facile synthesis of a peptidic Au(i)-metalloamphiphile and its self-assembly into luminescent micelles in water
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We report a short synthetic route for the preparation of a peptidic Au(i)-metalloamphiphile which, in buffered environments of physiological ionic strength, self-assembles into luminescent micellar nanostructures of 14 nm in diameter. This journal is
- Kemper, Benedict,Hristova, Yana R.,Tacke, Sebastian,Stegemann, Linda,Van Bezouwen, Laura S.,Stuart, Marc C. A.,Klingauf, Jürgen,Strassert, Cristian A.,Besenius, Pol
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- A catalytic one-step synthesis of peptide thioacids: the synthesis of leuprorelin via iterative peptide-fragment coupling reactions
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A catalytic one-step synthesis of peptide thioacids was developed. The oxygen-sulfur atom exchange reaction converted the carboxy group at the C-terminus of the peptides into a thiocarboxy group with suppressed epimerization. This method was successfully applied to the synthesis of the peptide drug leuprorelin via an iterative fragment-coupling protocol.
- Matsumoto, Takuya,Sasamoto, Koki,Hirano, Ryo,Oisaki, Kounosuke,Kanai, Motomu
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- Evaporation-Induced Self-Assembly of Small Peptide-Conjugated Silica Nanoparticles
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Self-assembly processes guide disordered molecules or particles into long-range organized structures due to specific supramolecular interactions among the building entities. Herein, we report a unique evaporation-induced self-assembly (EISA) strategy for four different silica nanoparticle systems obtained through peptide functionalization of the particle surface. First, covalent peptide-silica coupling was investigated in detail, starting with the grafting of a single amino acid (L-serine) and expanded to specific small peptides (up to four amino acids) and transferred to different particle types (MCM-48-type MSNs, solid nanoparticles, and newly developed virus-like nanoparticles). These materials were investigated regarding their ability to undergo EISA, which was shown to be independent of particle type and amount of peptide anchored to their surface. This EISA-based approach provides new possibilities for the design of future advanced drug delivery systems, engineered hierarchical sorbents, and nanocatalyst assemblies.
- von Baeckmann, Cornelia,Rubio, Guilherme M. D. M.,K?hlig, Hanspeter,Kurzbach, Dennis,Reithofer, Michael R.,Kleitz, Freddy
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- Electrostatic interaction and induced fitting of the rhodium(I) complex coordinated by diphosphine ligand having an amino group in the diastereoselective hydrogenation of dehydrodipeptides
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Rhodium(I)-[2-[2-(dimethylamino)ethyl]-1,3-propanediyl]bis(diphenylphosphine) (DPP-AE) catalyst achieved an effective 1,4-asymmetric induction and afforded high diastereoselectivity (max. 96% d.e.) in the hydrogenation of dehydrodipeptides in protic solve
- Yamada, Issaku,Fukui, Kouta,Aoki, Yoshihiro,Ikeda, Satoru,Yamaguchi, Motowo,Yamagishi, Takamichi
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- Tuning the mechanistic pathways of peptide self-assembly by aromatic interactions
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Herein, we have unravelled the key influence of aromatic interactions on the mechanistic pathways of peptide self-assembly by introducing suitable chromophores (pyrenevs.naphthalene). Although both self-assembled peptides are indistinguishable in their mo
- Ghosh, Goutam,Kartha, Kalathil K.,Fernández, Gustavo
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- A traceless approach to amide and peptide construction from thioacids and dithiocarbamate-terminal amines
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A novel and traceless strategy has been devised that allows a coupling of thioacids and dithiocarbamate-terminal amines. This strategy had been assumed to be dependent on the attachment of a functional equivalent of a cysteine side chain in earlier native chemical ligation approaches. This approach enables the traceless removal of CS2 to directly generate the desired amide bond and is compatible with a range of unprotected side chains of amino acid. The ability to produce amide or peptides by a traceless removal of the auxiliary is a significant virtue of the method. Meanwhile, the application of this new peptide-bond-forming reaction to the synthesis of novel endomorphin (EM) derivatives with various binding potencies was realized.
- Chen, Wenteng,Shao, Jiaan,Hu, Miao,Yu, Wanwan,Giulianotti, Marc A.,Houghten, Richard A.,Yu, Yongping
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p. 970 - 976
(2013/06/05)
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- Phenylalanine racemization: A side reaction of dipeptide formation
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It was shown that acetylated dipeptides, Ac-D-Phe-D-Phe-OH, Ac-L-Phe-L-Phe-OH, Ac-D-Phe-L-Phe-OH, and Ac-L-Phe-D-Phe-OH, are formed during D-phenylalanine racemization. The overall content of these dipeptides in the reaction mixture ranged from 40 to 60% depending on the reaction conditions. We concluded that, like α-aminoisobutyric acid, phenylalanine is prone to polymerization under racemization conditions.
- Kotlova,Timokhina,Chestukhina,Stepanov
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p. 579 - 583
(2007/10/03)
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- Efficient 1,4-Asymetric Induction Utilizing Electrostatic Interaction between Ligand and Substrate in the Asymmetric Hydrogenation of Didehydrodipeptides
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Electrostatic interaction between the amino group of the achiral 3-dimethylaminopropylidenebismethylenebis(diphenylphosphine) (1) and the carboxy group of the substrate enable an effective 1,4-asymmetric induction in the RhI-catalysed hydrogenation of didehydrodipeptides, to give (S,S)-or (R,R)-products selectively.The selectivity reached up to 94percent diastereoisomeric excess with acetyl didehydrodipeptides and 92percent with benzyloxycarbonyl substrates.
- Yamagishi, Takamichi,Ikeda, Satoru,Yatagai, Masanobu,Yamaguchi, Motowo,Hida, Mitsuhiko
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p. 1787 - 1790
(2007/10/02)
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- ASYMMETRIC HYDROGENATION WITH RHODIUM(I)-CHIRAL DIPHOSPHINITES. THE EFFECT OF THE DIMETHYLAMINO GROUP OF THE LIGAND ON THE ASYMMETRIC INDUCTION.
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New chiral diphosphinites were prepared starting from ( plus )-diethyl tartrate. The asymmetric hydrogenation of dehydroamino acids, itaconic acid and dehydrodipeptides was studied using Rh(I)-diphosphinite catalysts. In the hydrogenation of dehydroamino acid derivatives, an introduction of omega -(dimethylamino)alkyl group in the ligands did not raise the optical yield. By the use of Rh(I)-diphosphinite having 3-(dimethylamino)propyl group the inversion of the preferred product was observed. 19 refs.
- Yatagai,Zama,Yamagishi,Hida
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p. 739 - 746
(2007/10/02)
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- ASYMMETRIC HYDROGENATION OF DEHYDRODIPEPTIDES WITH RHODIUM(I)-CHIRAL DIPHOSPHINITES. SELECTIVE (S,S)- AND (R,R)-PRODUCT FORMATION BY DOUBLE ASYMMETRIC INDUCTION.
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In the hydrogenation of dehydrodipeptides, the effect of chiral center of the substrate ((S) or (R)) on the asymmetric induction was examined using the catalysts of Rh(I)-chiral diphosphinite containing pyrrolidine moiety (POP). The catalysts with POP's h
- Yatagai,Yamagishi,Hida
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p. 823 - 826
(2007/10/02)
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- ASYMMETRIC HYDROGENATION OF DEHYDROAMINO ACIDS AND DEHYDRODIPEPTIDES WITH RHODIUM(I)-MODIFIED DIOP CATALYSTS.
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( minus )-DIOP was modified in two ways: i), introduction of a large aromatic substituent at the dioxolane ring of ( minus )-DIOP and ii), replacement of one diphenylphosphino group by diarylphosphino group to give unsymmetrical DIOPs. Modification at the dioxolane ring had a small effect on the asymmetric induction by DIOP in the hydrogenation. Modification at the phosphino group affected the stereocontrol by the ligand and the unsymmetrical DIOP with di-2-naphthylphosphino group gave higher optical yields than ( minus )-DIOP for the hydrogenation of alpha -acetamidocinnamic acid and dehydrodipeptides.
- Yamagishi,Yatagai,Hatakeyama,Hida
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p. 1897 - 1901
(2007/10/02)
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- EFFECTIVE ASYMMETRIC HYDROGENATION OF DEHYDRODIPEPTIDES WITH RHODIUM(I)-NEW CHIRAL DIPHOSPHINITE SYSTEMS
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Rh(I)-new chiral diphosphinite systems with terminal amino groups were very effective for asymmetric hydrogenation of dehydrodipeptides with free carboxyl group and a chiral carbon.The effectiveness of the diphosphinite catalysts strongly suggests the contribution of electrostatic effect to asymmetric induction.
- Yatagai, Masanobu,Zama, Masanobu,Yamagishi, Takamichi,Hida, Mitsuhiko
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p. 1203 - 1206
(2007/10/02)
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- Synthesis of Chiral Dipeptides by means of Asymmetric Hydrogenation of Dehydro Dipeptides
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Asymmetric hydrogenation of various dehydro dipeptides was carried out by using rhodium complex catalysts with a variety of chiral diphosphine ligands.The efficiency of chiral diphosphine ligands as well as the effect of the chiral center in the substrate
- Ojima, Iwao,Kogure, Tetsuo,Yoda, Noriko,Suzuki, Tadashi,Yatabe, Momoko,Tanaka, Toshiyuki
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p. 1329 - 1334
(2007/10/02)
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- Stereoselective Synthesis of Dipeptides by Asymmetric Reduction of Dehydropeptides Catalyzed by Chiral Rhodium Complexes
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Asymmetric catalysis was used to control the creation of an asymmetric center in a chiral dehydropeptide.The reduction of Ac-ΔPhe-(S)-Phe-OR (R=H or Me) was studied as a model.Depending on the type of chiral rhodium catalyst used, it was possible to selec
- Meyer, Dominique,Poulin, Jean-Claude,Kagan, Henri B.,Levine-Pinto, Huguette,Morgat, Jean-Louis,Fromageot, Pierre
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p. 4680 - 4682
(2007/10/02)
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- Tripeptides, their esters and amides, and anti-ulcera activity thereof
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This invention relates to aseries of tripeptides of the general formula: STR1 wherein R = -- H, COCH3, alkyl R1 = --oh, --nh2, --nh alkyl (C1 -C5) --O alkyl (C1 -C5) resulting fr
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