- Postsynthetic Modification of Phenylalanine Containing Peptides by C-H Functionalization
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New methods for peptide modification are in high demand in drug discovery, chemical biology, and materials chemistry; methods that modify natural peptides are particularly attractive. A Pd-catalyzed, C-H functionalization protocol for the olefination of phenylalanine residues in peptides is reported, which is compatible with common amino acid protecting groups, and the scope of the styrene reaction partner is broad. Bidentate coordination of the peptide to the catalyst appears crucial for the success of the reaction.
- Terrey, Myles J.,Perry, Carole C.,Cross, Warren B.
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p. 104 - 108
(2019/01/11)
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- Oxidative damage of aromatic dipeptides by the environmental oxidants NO2 and O3
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Irreversible oxidative damage at both aromatic side chains and dipeptide linkage occurs in the aromatic N- and C-protected dipeptides 7-11 upon exposure to the environmental pollutants NO2 and O3. The reaction proceeds through initial oxidation of the aromatic ring by in situ generated NO3, or by NO2, respectively, which leads to formation of nitroaromatic products. The indole ring in Phe-Trp undergoes oxidative cyclization to a pyrroloindoline. An important reaction pathway for dipeptides with less oxidisable aromatic side chains proceeds through fragmentation of the peptide bond with concomitant acyl migration. This process is likely initiated by an ionic reaction of the amide nitrogen with the NO2 dimer, N2O4. This journal is
- Gamon,White,Wille
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supporting information
p. 8280 - 8287
(2015/01/08)
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- Direct amidation of amino acid derivatives catalyzed by arylboronic acids: Applications in dipeptide synthesis
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The direct amidation of amino acid derivatives catalyzed by arylboronic acids has been examined. The reaction was generally slow relative to simple amine-carboxylic acid combinations though proceeded at 65-68 °C generally avoiding racemization. 3,4,5-Trifluorophenylboronic and o-nitrophenylboronic acids were found to be the best catalysts, though for slower dipeptide formations, high catalyst loadings were required and an interesting synergistic catalytic effect between two arylboronic acids was discovered. Arylboronic acids can be used to catalyze the direct amide formation of protected amino acid derivatives. For less reactive amino acids, cooperative catalysis can be used involving two arylboronic acids, one electron-rich and one electron-deficient, at high catalyst loadings to give good conversions at moderate temperatures. Copyright
- Liu, Shouxin,Yang, Yihua,Liu, Xinwei,Ferdousi, Farhana K.,Batsanov, Andrei S.,Whiting, Andrew
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p. 5692 - 5700
(2013/09/12)
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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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- METHOD FOR STORING QUATERNARY AMMONIUM SALT
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A method of improving the stability of a quaternary ammonium salt and a method of efficiently preparing the quaternary ammonium salt having improved stability.
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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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- Intermolecular β-sheet stabilization with aminopyrazoles
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3-Aminopyrazole derivatives are the first artificial templates that stabilize the β-sheet conformation in N/C-protected dipeptides by purely intermolecular interactions. In the complex two aminopyrazole molecules lie exactly above and below the peptide ba
- Kirsten, Christian N.,Schrader, Thomas H.
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p. 12061 - 12068
(2007/10/03)
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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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p. 115 - 120
(2007/10/03)
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- Tandem asymmetric syntheses from achiral precursors. Asymmetric homogeneous reduction of bisdehydrodipeptides
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Sequential asymmetric syntheses on an achiral substrate with two prochiral centers is a direct route to products with two asymmetric centers.The product distribution is discussed as a function of the various stereoselectivities.After a general presentation of double asymmetric syntheses, the specific case of asymmetric hydrogenation of some achiral bisdehydrodipeptides is considered.When the chiral ligand of the rhodium catalyst was dipamp, very high diastereoselectivities and enanatioselectivities with respect to resulting dipeptides could be achieved. bisdehydrodipeptides / dipeptides / diop / dipamp / bppm / two sequential asymmetric syntheses / stereoselective hydrogenation / enantioselectivity / diastereoselectivity
- Baba, Sana El,Sartor, Karina,Poulin, Jean-Claude,Kagan, Henri B.
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p. 525 - 533
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF AMINO ACIDS VIA THE CATALYTIC REDUCTION OF ACYLAMINOACRYLIC ACID AZLACTONE DERIVATIVES. 24. REDUCTIVE AMINOLYSIS OF 2-METHYL-4-BENZYLIDENE-Δ2-OXAZOLIN-5-ONE UPON TREATMENT WITH A CATALYTIC SYSTEM BASED ON S-PHENYLALANINE DERIVATIVES
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Reductive aminolysis of 2-methyl-4-benzylidene-Δ2-oxazolin-5-one upon treatment with a PdCl2-S-phenylalanine ester (dimethylamide) catalytic system leads to the formation of the corresponding acylated dipeptide derivatives, with the R,S-configuration (diastereomer) predominating (DE 9-27percent).The reaction stereoselectivity in dimethoxyethane increases sharply in the presence of triethylamine additive, and in the case of S-phenylalanine methyl ester reaches 47percent.The stepwise mechanism for this process has been studied.
- Lyubeznova, M. R.,Karpeiskaya, E. I.,Klabunovskii, E. I.
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p. 720 - 726
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF AMINO ACIDS VIA THE CATALYTIC REDUCTION OF SUBSTITUTED ACYLAMINOACRYLIC ACID AZLACTONES. 26. AMINOLYSIS OF 2-METHYL-4-BENZYLOXAZOLIN-5-ONE UPON REACTION WITH S-PHENYLALANINE DERIVATIVES
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The kinetics of aminolysis and racemization of 2-methyl-4-benzyloxazolin-5-one upon reaction with S-phenylalanine methyl ester have been studied in dimethoxyethane solvent.The rates of aminolysis and racemization are comparable.Addition of an achiral component, namely Et3N, to the reaction mixture, however, dramatically increases the rate of racemization.The presence of Et3N also increases the ratio of rate constants for the formation of RS- and SS-diastereomers, which determines the reaction stereoselectivity.
- Lyubeznova, M. R.,Karpeiskaya, E. I.,Klabunovskii, E. I.,Koreshkov, Yu. D.,Lutsenko, A. I.,Lubuzh, E. D.
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p. 731 - 737
(2007/10/02)
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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 HOMOGENOUS REDUCTION OF DEHYDROPEPTIDES
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Monodehydropeptides with the dehydroaminoacid fragment in C-terminal or N-terminal position were synthetized as well as a family with the general formula Ac-ΔPhe-(Gly)n-Leu-OR (n = 0-2, R = H or Me).Asymmetric reduction of these compounds catalyzed by chiral rhodium complexes was investigated.The results were discussed in terms of double asymmetric induction.A method was developped to avoid the use of both enantiomers of the substrate or of the catalyst, it consists in the total reduction of a racemic dehydropeptide.The products distribution gives access to the two desired facial selectivities.
- El-Baba, S.,Nuzillard, J. M.,Poulin, J. C.,Kagan, H. B.
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p. 3851 - 3862
(2007/10/02)
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- Synthesis and Conformation of Aromatic Cyclic Dipeptides. Cyclo(phenylalanyl)2, Cyclo(1-naphthylalanyl)2, and Cyclo(2-naphthylalanyl)2
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Cyclic dipeptides of aromatic amino acids, cyclo(L-phenylalanyl)2, cyclo(L-1-naphthylalanyl)2, and cyclo(L-2-naphthylalanyl)2 were synthesized and subjected to spectroscopic analyses using 1H NMR, absorption, circular dichroism (CD), fluorescence, and fluoroscence-detected circular dichroism (FDCD).The 1H NMR data suggested that the 2,5-piperazinedione rings of the three cyclic dipeptides are in planar or nearly planar bowsplitboat-type conformation.The aromatic side groups of cyclo(1- and 2-naphthylalanyl)2's were found to take asymmetric configurations, one naphthyl group being folded onto the 2,5-piperazinedione ring, the order being unfolded.Strong exciton couplet was observed in CD spectra of the three compounds.The signs of the exciton splitting were opposite in the two naphthyl cyclic dipeptides.Fluorescence spectra of the two naphthyl cyclic dipeptides showed no excimer emission.The absence of strong interchromophoric interaction in the lowest excited state was also suggested by the virtual coincidence of CD spectrum with FDCD spectrum.From the above spectroscopic data, probable conformations were proposed for the naphthyl cyclic dipeptides.
- Egusa, Syun,Takagi, Jun,Sisido, Masahiko,Imanishi, Yukio
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p. 2195 - 2202
(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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- A Direct Preparation of Acetyl-(S)-phenylalanyl-(S)-phenylalanine Methyl Ester by a Double Asymmetric Hydrogenation
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Acetyl-(S)-phenylalanyl-(S)-phenylalanine methyl ester is obtained with high diastereoselectivity and enantioselectivity by catalytic hydrogenation, using +BF4- (dipamp = R,R-1,2-bis(2-methoxyphe
- Poulin, Jean-Claude,Kagan, Henri B.
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p. 1261 - 1262
(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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