- Coupling-Reagent-Free Synthesis of Dipeptides and Tripeptides Using Amino Acid Ionic Liquids
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A general method for the synthesis of dipeptides has been developed, which does not require any coupling reagents. This method is based on the reaction of readily available HCl salts of amino acid methyl esters with tetrabutylphosphonium amino acid ionic liquids. The isolation procedure of stepwise treatment with AcOH is easy to carry out. The method was extended to the synthesis of tripeptide, tyrosyl-glycyl-glycine, present in IMREG-1, also.
- Furukawa, Shinya,Fukuyama, Takahide,Matsui, Akihiro,Kuratsu, Mai,Nakaya, Ryotaro,Ineyama, Takashi,Ueda, Hiroshi,Ryu, Ilhyong
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supporting information
p. 11980 - 11983
(2015/08/18)
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- The dimethylsulfoxonium methylide as unique reagent for the simultaneous deprotection of amino and carboxyl function of N-Fmoc-α-amino acid and N-Fmoc-peptide esters
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The dimethylsulfoxonium methylide is described as a unique and useful reagent for the simultaneous deprotection of amino and carboxyl function of N-Fmoc-α-amino acid and N-Fmoc-peptide esters. The new methodology was applied successfully both to solution- and solid-phase peptide synthesis. The adopted methodology was extended successfully also to peptides containing amino acids bearing acid-sensitive protecting group in side chains. Furthermore no measurable epimerization was observed in the deprotection reaction of N-Fmoc-dipeptide methyl esters with dimethylsulfoxonium methylide.
- Spinella, Mariagiovanna,De Marco, Rosaria,Belsito, Emilia L.,Leggio, Antonella,Liguori, Angelo
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p. 2010 - 2016
(2013/03/13)
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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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- DIPEPTIDE-CONTAINING COMPOSITION FOR ORAL ADMINISTRATION
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The present invention provides a composition for oral administration, which comprises at least one kind of dipeptide represented by the formula: ????????X-Y (wherein X represents alanyl, glycyl, arginyl, seryl, α-aspartyl or α-glutamyl, and Y represents valine, leucine or isoleucine), with an object of providing a composition for oral administration which is excellent in nutrition, pharmacological effect and gustation and comprises at least one kind selected from valine, leucine and isoleucine, or providing a composition for oral administration which is excellent in processing characteristics such as solubility and tableting property and comprises at least one kind selected from valine, leucine and isoleucine.
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Page/Page column 6-7
(2008/12/06)
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- Direct asymmetric intermolecular aldol reactions catalyzed by amino acids and small peptides
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In nature there are at least nineteen different acyclic amino acids that act as the building blocks of poly-peptides and proteins with different functions. Here we report that α-amino acids, β-amino acids, and chiral amines containing primary amine functions catalyze direct asymmetric intermolecular aldol reactions with high enantio-selectivities. Moreover, the amino acids can be combined into highly modular natural and unusual small peptides that also catalyze direct asymmetric intermolecular aldol reactions with high stereoselectivities, to furnish the corre sponding aldol products with up to > 99% ee. Simple amino acids and small peptides can thus catalyze asymmetric aldol reactions with stereoselectivities matching those of natural enzymes that have evolved over billions of years. A small amount of water accelerates the asymmetric aldol reactions catalyzed by amino acids and small peptides, and also increases their stereoselectivities. Notably, small peptides and amino acid tetrazoles were able to catalyze direct asymmetric aldol reactions with high enantioselectivities in water, while the parent amino acids, in stark contrast, furnished nearly racemic products. These results suggest that the prebiotic oligomerization of amino acids to peptides may plausibly have been a link in the evolution of the homochirality of sugars. The mechanism and stereochemistry of the reactions are also discussed.
- Cordova, Armando,Zou, Weibiao,Dziedzic, Pawel,Ibrahem, Ismail,Reyes, Efraim,Xu, Yongmei
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p. 5383 - 5397
(2008/02/13)
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- Small peptides as modular catalysts for the direct asymmetric aldol reaction: Ancient peptides with aldolase enzyme activity
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Simple peptides and their analogues having a primary amino group as the catalytic residue mediate the direct asymmetric intermolecular aldol reaction with high stereoselectivity and furnish the corresponding aldol products with up to 99% ee; this intrinsic ability of highly modular peptides may explain the initial molecular evolution of aldolase enzymes. The Royal Society of Chemistry 2005.
- Zou, Weibiao,Ibrahem, Ismail,Dziedzic, Pawel,Sunden, Henrik,Cordova, Armando
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p. 4946 - 4948
(2007/10/03)
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- Gas-phase basicity measurements of dipeptides that contain valine
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Gas-phase basicities of 22 dipeptides that contain valine were measured by a double bracketing method in a Fourier transform ion cyclotron resonance spectrometer. Matrix-assisted laser desorption was used to generate protonated peptide ions which were reacted with reference compounds to bracket the gas-phase basicity. In addition, neutral peptide molecules were formed by substrate-assisted laser desorption and with protonated reference ions to confirm the assignment of the gas-phase basicity. The rate of proton transfer between the protonated molecule of alanylvaline and six reference compounds was measured to examine the behavior of both exoergic and endoergic reactions. Gas-phase basicities of most of the dipeptides were found to be nearly equal to that of their most basic amino acid residue. The results are consistent with an intramolecular hydrogen bond between the N-terminus nitrogen and the amide carbonyl oxygen of a dipeptide. Furthermore, the results suggest that inductive effects cause an increase in the strength of the intramolecular hydrogen bond that the in the basicity of the C-terminus amino acid residue. Dipeptides VF and VY are more basic than their constituent amino acids. These data and molecular mechanics calculations suggest that these two peptides are stabilized by an electrostatic interaction between the N-terminal ammonium ion and the polarizable electrons of the aromatic side chain of the C-terminus.
- Gorman, Greg S.,Amster
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p. 5729 - 5735
(2007/10/02)
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- A NEW FLUORIDOLYSABLE ANCHORING LINKAGE FOR ORTHOGONAL SOLID-PHASE PEPTIDE SYNTHESIS: PREPARATION AND PROPERTIES OF THE N-(3 OR 4)-SILYL>PHENYL>PENTANEDIOIC ACID, MONOAMIDE (PBS) HANDLE
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The synthesis and characterization of a new silicon-containing handle for use in solid-phase synthesis is described.The anchoring linkage derived from this new handle, when treated with fluoride (1.0 equiv.) for 5 min at 25 deg C, releases peptides as their free acids in essentially quantitative yields and without racemization.
- Mullen, Daniel G.,Barany, George
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p. 491 - 494
(2007/10/02)
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