Search results for "Peptide synthesis"
showing 10 items of 39 documents
Hierarchical Imprinting Using Crude Solid Phase Peptide Synthesis Products as Templates
2003
The crude products resulting from solid-phase peptide synthesis can be used as epitope templates to generate surface-confined sites for the template and larger peptides containing the template motif. This offers a facile route to robust affinity stationary phases for the chromatographic separation of peptides.
1H-nmr studies of polyoxyethylene-bound homo-oligo-L-methionines
1982
The use of 1H-nmr spectroscopy is demonstrated to be a useful analytical method to characterize the structure of synthetic peptides attached to soluble, macromolecular polyoxyethylene (POE) supports in the liquid-phase method (LPM) of peptide synthesis. We report an extensive 360-MHz 1H-nmr study of POE-bound homo-oligo-L-methionine peptides. A combination of high field and selective saturation or Redfield pulse methods allows resolution of individual backbone NH and α-CH resonances of dilute peptides in the presence of strong resonances from macromolecular POE and/or protonated solvents. The nmr spectra for the POE-bound peptides in CDCl3 are qualitatively similar to those of the low-molec…
Soluble polymers in organic synthesis
1982
The end function of polyethylene glycol was transferred to the tertiary alcohol for use as acid labile, solubilizing protecting group in peptide synthesis.
Exploring new activating groups for reactive cysteine NCAs
2016
Abstract Due to its ability to reversibly crosslink proteins, cysteine has a unique role as an amino acid in nature. For controlled, asymmetric formation of disulfides from two thiols, one thiol needs to be activated. While few activating groups for cysteine have been proposed, they are usually not stable against amines making them unsuitable for solid phase peptide synthesis or amine initiated polymerization of α-amino acid-N-carboxy-anhydrides (NCAs). In this Letter we describe a series of new thiol activated cysteines, as well as their NCAs and explore the link between electron deficiency of the leaving group and control over NCA polymerization.
Evaluating chemical ligation techniques for the synthesis of block copolypeptides, polypeptoids and block copolypept(o)ides: a comparative study
2015
In this work, we describe the synthesis of block copolypeptides, polypeptoids and block copolypept(o)ides by chemical ligation techniques. Polysarcosine (PSar), poly(N-e-trifluoroacetyl-L-lysine) (PLys(TFA)) and poly(γ-benzyl-L-glutamate) (PGlu(OBzl)) homopolymers of different polarities and end group functionalities but with similar average degrees of polymerization (Xn = 50 and 100) could be obtained by ring opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCA) and postpolymerization modification reactions. In the next step, these polymers were applied to copper(I)-catalyzed azide–alkyne coupling (CuAAC), strain-promoted azide–alkyne coupling (SPAAC) and native chemical l…
Conformational preferences of side-chain protected amino acid residues and their impact in peptide synthesis
1983
Using the host-guest technique, tentative scales for the helix-inducing power and the β-structure-forming potential of various side-chain protected amino acid residues in trifluoro-ethanol are established mainly by CD measurements. The generally lower tendency for β-structure formation of the host–guest peptides compared to that of the host peptide is discussed. The influence of these conformational features on the solubility of the peptides is also pointed out.
Fluorous (Trimethylsilyl)ethanol: A New Reagent for Carboxylic Acid Tagging and Protection in Peptide Synthesis
2006
Starting with a fluorous analogue of 2-(trimethylsilyl)ethanol, we have designed an easy method for preparing a new fluorous tag ((F)TMSE) for the protection of carboxylic acids. Because mild conditions are employed in the tag cleavage (TBAF in the presence of 4 A molecular sieves, which prevent racemization), this tag can be advantageously used in the synthesis of peptides and modified peptides, as we have demonstrated with several examples, including the fluorous synthesis of short alpha- and beta-peptides as well as of modified fluorinated retropeptides.
Convenient High Yielding Gram Scale Solution Synthesis of Methionine-Enkephalin.
1998
A simple, large-scale synthesis of a cytokine, methionine-enkephalin, Tyr-Gly-Gly-Phe-Met, has been elaborated. Classical solution peptide chemistry methods without protection of amino acid side-chain functions and 1+(2+2) segment condensation were used. A nine-step synthesis from commercial amino acid derivatives was developed with yields ranging from 86% to 99%, averaging 92%. The purity of all intermediates was found to be 99.0-100% by HPLC. The process has been used to prepare greater than 150 g quantities of the pentapeptide as a monohydrate of 100% purity. Hydantoin formation was observed during saponification of Boc-Tyr-Gly-Gly-Phe-Met-OMe and minimised.
Umwandlung von 2-Bromäthoxycarbonyl-Schutzgruppen in 2-Phosphonioäthoxycarbonyl-Schutzgruppen für Aminosäuren1)
1976
Die Bromide 2 von 2-Phosphonioathoxycarbonylaminosauren (Peoc-Aminosauren) werden durch Umsetzung von 2-Bromathoxycarbonylaminosauren (Beoc-Aminosauren) mit tertiaren Phosphinen erhalten. Hierbei entstehen durch Reaktion mit Methyl(diphenyl)phosphin die mit der modifizierten Peoc-Gruppe geschutzten Verbindungen 2e - h in besonders guten Ausbeuten. Diese eignen sich zur Peptidsynthese nach dem Carbodiimid-Verfahren und sind besser in Wasser loslich als die entsprechenden Triphenylphosphonium-Derivate. Die Abspaltung der Me(Ph2)Peoc-Gruppe gelingt mit 0.01 N NaOH in Methanol/Wasser. Modification of 2-Brornoethoxycarbonyl Protective Groups to 2-Phosphonioethoxycarbonyl Protective Functions of …
Die 2-(Triphenylphosphonio)isopropyloxycarbonyl-(Ppoc-)-Gruppe und am Phosphoniumzentrum modizifierte analoge Reste als Aminoschutzgruppen bei der Pe…
1985
Die Einfuhrung in Aminosauren, die Stabilitat bei Peptidsynthesen und die selektive Abspaltung der 2-(Triphenylphosphonio)isopropyloxycarbonyl-(Ppoc-)-Aminoschutzgruppe sowie ihrer Varianten mit (Methyl)(diphenyl)phosphonium- und (Dimethyl)(phenyl)phosphoniumkopfen werden beschrieben. Der Ppoc-Rest ist in etwa um den Faktor 4 basenstabiler als der entsprechende 2-(Triphenylphosphonio)ethoxycarbonyl-(Peoc-)Rest. Er kann dennoch bereits bei pH = 8 in wasrig-methanolischer Hydrogencarbonatlosung von der blockierten Aminofunktion abgelost werden. Im Gegensatz zur Peoc-Abspaltung treten dabei keine storenden Nebenreaktionen des entstehenden Propenylphosphoniumsalzes mit der freigesetzten Aminofu…