Über aktivierte Ester. I. Aktivierte Ester der Hippursäure und ihre Umsetzungen mit Benzylamin
TL;DR: In this article, a number of activated esters of hippuric acid are compared and the best acylating agent seems to be the cyanomethylester which is an easily accessible, cristalline, and stable compound, reacting easily with benzylamine at room temperature.
Abstract: Introduction of electron-attracting substituents into the alcoholic component of methyl-hippurate leads to activated esters which are characteristic acylating agents. A number of activated esters of hippuric acid are compared. The best acylating agent seems to be the cyanomethylester which is an easily accessible, cristalline, and stable compound, reacting easily with benzylamine at room temperature.
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TL;DR: This protocol for solid-phase peptide synthesis (SPPS) is based on the widely used Fmoc/tBu strategy, activation of the carboxyl groups by aminium-derived coupling reagents and use of PEG-modified polystyrene resins.
Abstract: This protocol for solid-phase peptide synthesis (SPPS) is based on the widely used Fmoc/tBu strategy, activation of the carboxyl groups by aminium-derived coupling reagents and use of PEG-modified polystyrene resins. A standard protocol is described, which was successfully applied in our lab for the synthesis of the corticotropin-releasing factor (CRF), >400 CRF analogs and a countless number of other peptides. The 41-mer peptide CRF is obtained within approximately 80 working hours. To achieve the so-called difficult sequences, special techniques have to be applied in order to reduce aggregation of the growing peptide chain, which is the main cause of failure for peptide chemosynthesis. Exemplary application of depsipeptide and pseudoproline units is shown for synthesizing an extremely difficult sequence, the Asn(15) analog of the WW domain FBP28, which is impossible to obtain using the standard protocol.
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TL;DR: Pentafluorophenyl acrylate and -methacrylate were polymerized using AIBN as a thermal initiator and the obtained polymers were soluble polymeric active esters that could be used for the preparation of multifunctional polymers as discussed by the authors.
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TL;DR: In this paper, two different research areas of activated esters in polymer science are discussed: (i) the preparation of defined reactive polymer architectures by controlled polymerization techniques and (ii) the prepared reactive thin films.
Abstract: Monomers bearing an activated ester group can be polymerized under various controlled polymerization techniques, such as ATRP, NMP, RAFT polymerization, or ROMP. Combining the functionalization of polymers via polymeric activated esters with these controlled polymerization techniques generate possibilities to realize highly functionalized polymer architectures. Within this highlight two different research areas of activated esters in polymer science will be discussed: (i) the preparation of defined reactive polymer architectures by controlled polymerization techniques and (ii) the preparation of defined reactive thin films. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6677–6687, 2008
265 citations
TL;DR: The methods used to establish the chemical constitution of the polymers and their average molecular weights are given and the most suitable and commonly used are the N-carboxy-α-amino acid anhydrides.
Abstract: Publisher Summary The chapter discusses the synthesis and chemical properties of poly-α-amino acids Poly-α-amino acids are synthetic polymers composed of α-amino acid residues linked by peptide bonds They are prepared by polymerization of the corresponding monomers and consist, like other synthetic polymers, of mixtures of homologous macromolecules of varying chain length The preparative methods developed permit the synthesis of a large variety of α-amino acid polymers, in a wide range of average molecular weights A number of different derivatives of α-amino acids and peptides have been used as monomers for the preparation of poly-α-amino acids; the most suitable and commonly used are the N-carboxy-α-amino acid anhydrides (NCAs) These readily undergo polymerization, with carbon dioxide evolution, to yield the corresponding poly-α-amino acids The synthesis of amino acid polymers from the monomers may be accompanied by varying amounts of byproducts that should be removed, during the isolation and purification of the polymer The purification techniques applied are described in the chapter In addition, the methods used to establish the chemical constitution of the polymers and their average molecular weights are given
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TL;DR: This chapter focuses on the available methods for the synthesis of peptides and evaluates their relative difficulty, their adaptability to meet problems encountered in amino acid chemistry, and the yield and purity of the products of synthesis.
Abstract: Publisher Summary The usefulness of peptide synthesis to protein chemistry is abundant. Modern methods of peptide synthesis allows the preparation of special peptides of low molecular weight and known chemical structure for use as models in the examination of several physical and chemical properties of proteins. The usage of synthetic peptides also facilitates the interpretation of data on the acid-base relationships of proteins. They also provide simple models for the study of the enzymatic degradation, physical properties, or chemical reactions of proteins along with the final proof of the chemical structure of several physiologically important substances, such as glutathione and carnosine. This chapter focuses on the available methods for the synthesis of peptides. These methods are evaluated with regard to their relative difficulty, their adaptability to meet problems encountered in amino acid chemistry, and the yield and purity of the products of synthesis. The chapter emphasizes on the synthesis of peptides of amino essentially formed upon protein hydrolysis. Configurational relationships of peptides are also presented.
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57 citations
TL;DR: In this paper, the reactivity of esters of thiolcarboxylic acids with amino compounds is strongly and specifically enhanced by metal ions possessing affinity for the sulfur atom.
Abstract: The reactivity of esters of thiolcarboxylic acids with amino compounds is strongly and specifically enhanced by metal ions possessing affinity for the sulfur atom. Model reactions of the enzymatic acylation of aromatic amines and of the biological synthesis of hippuric acid are described, using benzoyl pantetheine as a model compound for acyl derivatives of coenzyme A, and metal ions as models for the corresponding acetylases.
47 citations