Lithium‐Salt Effects in Peptide Synthesis. Part II. Improvement of Degree of Resin Swelling and of Efficiency of Coupling in Solid‐Phase Synthesis

Thaler, Adrian; Seebàch, Dieter; Cardinaux, F.

doi:10.1002/hlca.19910740320

Cited by 66 publications

(25 citation statements)

References 38 publications

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“…The fourth hypothesis is that the coupling reaction for steps a and c was incomplete due to aggregation of the growing chain. Few conditions to overcome this potential problem of aggregation were evaluated including (1) reducing the loading density on the resin, i.e., the targeted loading of the resin with the first phenylalanine residue was half (Table , entry 5; Figure S4, entry 5, Supporting Information), (2) improving the solvation of the growing chain by either adding dichloromethane, i.e., 1/1 DMF/CH 2 Cl 2 (Table , entry 6; Figure S4, entry 6, Supporting Information), as CH 2 Cl 2 has a superior capacity to swell the resin as compared to DMF, or adding chaotropic salts such as lithium chloride (Table , entry 7; Figure S4, entry 7, Supporting Information), (3) conducting steps a and c under microwave irradiations (Table , entry 8; Figure S4, entry 8, Supporting Information), or (4) using a Tentagel resin (Table , entry 9; Figure S4, entry 9, Supporting Information) that is reported to have a kinetic behavior of its reactive sites similar to those in solution chemistry. None of the attempts conducted to noticeable positive changes.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Macromolecules Containing Phenylalanine and Aliphatic Building Blocks

Chan‐Seng

Louwsma

Lutz

et al. 2018

Macromol. Rapid Commun.

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Aiming at developing efficient interfacial agents for fiber-reinforced composite materials, macromolecules are designed to have different components able to stick to the fiber and be compatible with the polymer matrix, respectively. Herein, macromolecules are prepared by solid-phase synthesis considering phenylalanine residues to promote adsorption of the macromolecule on aramid fibers and aliphatic building blocks to interact with a hydrophobic polymer matrix. Using phenylalanine as building block for the preparation of macromolecules by iterative synthesis has been shown to be challenging. Thus, the screening of various parameters for the optimization of the synthesis of these macromolecules is discussed in this communication. A preliminary thermal study by thermal gravimetric analysis is conducted to evaluate their thermal stability.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Macromolecules Containing Phenylalanine and Aliphatic Building Blocks

Chan‐Seng

Louwsma

Lutz

et al. 2018

Macromol. Rapid Commun.

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“…Subsequently, anhydrous solvents such as DMF, NMP, and THF, or the binary mixture DMF/DCM (1 : 1), containing or not LiCl, LiBr, KSCN, or NaClO 4 , were employed in solid-phase coupling reactions starting from Fmoc-(Ala) 5 Phe, a wellknown difficult peptide sequence, on polystyrene, poly(N,N-dimethylacrylamide) kieselguhr (PDMAA-KG), and poly(ethylene oxide) (PEO)-PS resins. The results obtained indicated that the reaction yields were mainly enhanced in the presence of the lithium salts due to swelling enhancement of the peptide-resins [113].…”

Section: Use Of Chaotropic Salts During Peptide Chain Assemblymentioning

confidence: 99%

Difficult Peptides

Miranda

and

Remuzgo

2010

Amino Acids, Peptides and Proteins in Organic Chemistry

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As thousands of biologically active peptides have been discovered in the last 50 years, to date no one contests that all living organismsfrom bacteria to mammals and complex plant formsproduce such compounds for vital purposes. A few examples are given in Table 16.1.In association with the first discoveries of biologically active peptides, it was noted that natural sources could provide quite restricted amounts of them. At that time, the composition and structure of proteins were not sufficiently understood and the ribosomal machinery remained unknown. Hence, many first-rate chemists started searching for methods, procedures, and protocols that could allow for the preparation of peptides in a variable range of scales and purities. Such circumstances turned peptide synthesis into an important research topic [1,2].In the following decades, peptide synthesis reached a high level of efficacy, and also became a fundamental tool for research in the chemistry and biology of these macromolecules [1,3]. Indeed, most of the current knowledge on peptide hormones, antibiotics, cytotoxins, opioids, and hormone-releasing factors has been generated with the help of synthetics.Peptide synthesis has also been critical for providing a wide range of information in biochemistry, medicine, biology, and chemistry as its applications include: (i) therapeutic purposes [4,5]; (ii) development of techniques for peptide detection, separation, identification, quantification, and analysis [6, 7]; (iii) characterization of proteinase-substrate or inhibitor interactions [8,9]; (iv) study of protein-protein interactions and the basis of protein folding [10,11]; (v) mapping of protein epitopes [12, 13]; (vi) mimicking of enzyme activity [14, 15]; (vii) engineering of new peptide-based drugs with therapeutic potential [16, 17]; (viii) design of new biomaterials [18, 19]; (ix) synthesis of prodrugs [20, 21]; and (x) chemical synthesis of proteins [22, 23].Despite these advances, peptide synthesis remains a research topic that attracts an impressive number of scientists worldwide. Most current studies focus

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“…In most cases the target molecule is almost impossible to be isolated. The use of polar solvents (DMF, 25% DMSO in DMF v/v) [37][38][39], chaotropic salts (like 0.8 M NaClO 4 or LiCl or 4 M KSCN in DMF) before coupling [40], neutralization in situ in the Boc chemistry solid phase peptide synthesis [35,41,42], capping procedures [43][44][45], and N,O-bis-Fmoc-amino acid 2hydroxy-4-methoxybenzyl (Hmb) derivatives [46][47][48][49][50] are some of the approaches which were introduced in order to improve efficiency of the stepwise chemical synthesis of proteins. This causes lower reaction rates and therefore low coupling yields.…”

Section: Stepwise Solid Phase Synthesis Of Proteins and Protein-like mentioning

confidence: 99%

Synthetic Approaches for Total Chemical Synthesis of Proteins and Protein-Like Macromolecules of Branched Architecture

Papas¹,

Strongylis²,

Tsikaris

2006

COC

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The progress achieved both in the solid and liquid phase of the synthetic methodologies for peptides, permitted the application of various chemistries for preparing totally synthetic proteins and protein-like macromolecules of branched architecture. Polypeptides with molecular masses in the 10-25 kDa range have been successfully prepared using either the step by step and fragment condensation or the chemoselective ligation methods. Amide, thioether, disulfide, thioester, hydrazone, oxime and thiazolidine linkages have been employed in such syntheses. Fully active proteins or macromolecules mimicking particular protein properties especially in immunology have been synthesized in high purity and large quantities. The branched constructs have found numerous applications in immunology due to their contribution in overcoming the very low ability of short linear peptides to react specifically with antibodies or to induce an immune response. The advantages over almost all the other methods of using synthetic carriers for developing potent antigens and immunogens have placed this approach at the center of extensive research activities. This review focuses on the concept and synthetic strategies suitable for assembling proteins or protein-like macromolecules of branched architecture with application in protein function studies and immunology.

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Lithium‐Salt Effects in Peptide Synthesis. Part II. Improvement of Degree of Resin Swelling and of Efficiency of Coupling in Solid‐Phase Synthesis

Cited by 66 publications

References 38 publications

Synthesis of Macromolecules Containing Phenylalanine and Aliphatic Building Blocks

Synthesis of Macromolecules Containing Phenylalanine and Aliphatic Building Blocks

Difficult Peptides

Synthetic Approaches for Total Chemical Synthesis of Proteins and Protein-Like Macromolecules of Branched Architecture

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