Comparative acidic cleavage experiments with methyl-substituted benzyl esters of amino acids

1967 ◽  
Vol 20 (10) ◽  
pp. 2243 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Amino Acid ◽  
Solid Phase ◽  
Hydrogen Bromide ◽  
Solid Phase Peptide Synthesis ◽  
Amino Acid Derivatives ◽  
Methyl Substitution ◽  
Benzyl Esters ◽  
Layer Chromatography

The action of trifluoroacetic acid and hydrogen bromide in acetic acid, respectively, on the benzyl, p-methylbenzyl, 2,4,6-trimethylbenzyl, and penta-methylbenzyl esters of some amino acid derivatives has been investigated by thin-layer chromatography. Methyl substitution greatly enhances the lability of the ester groups. The possible bearing of the results on solid-phase peptide synthesis is discussed.

scholarly journals Antifreeze glycopeptide diastereomers

2012 ◽  
Vol 8 ◽  
pp. 1657-1667 ◽  
Author(s):  
Lilly Nagel ◽  
Carsten Budke ◽  
Axel Dreyer ◽  
Thomas Koop ◽  
Norbert Sewald
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Antarctic Fish ◽  
Building Blocks ◽  
The Body ◽  
Ice Recrystallization ◽  
Harsh Conditions ◽  
Antifreeze Activity

Antifreeze glycopeptides (AFGPs) are a special class of biological antifreeze agents, which possess the property to inhibit ice growth in the body fluids of arctic and antarctic fish and, thus, enable life under these harsh conditions. AFGPs are composed of 4–55 tripeptide units -Ala-Ala-Thr- glycosylated at the threonine side chains. Despite the structural homology among all the fish species, divergence regarding the composition of the amino acids occurs in peptides from natural sources. Although AFGPs were discovered in the early 1960s, the adsorption mechanism of these macromolecules to the surface of the ice crystals has not yet been fully elucidated. Two AFGP diastereomers containing different amino acid configurations were synthesized to study the influence of amino acid stereochemistry on conformation and antifreeze activity. For this purpose, peptides containing monosaccharide-substituted allo-L- and D-threonine building blocks were assembled by solid-phase peptide synthesis (SPPS). The retro-inverso AFGP analogue contained all amino acids in D-configuration, while the allo-L-diastereomer was composed of L-amino acids, like native AFGPs, with replacement of L-threonine by its allo-L-diastereomer. Both glycopeptides were analyzed regarding their conformational properties, by circular dichroism (CD), and their ability to inhibit ice recrystallization in microphysical experiments.

scholarly journals Efficient Synthesis of Peptides with 4-Methylpiperidine as Fmoc Removal Reagent by Solid Phase Synthesis

2017 ◽  
Vol 58 (4) ◽  
Author(s):  
Javier Eduardo García Castañeda ◽  
Cristian Francisco Vergel Galeano ◽  
Zuly Jenny Rivera Monroy ◽  
Javier Eduardo Rosas Pérez
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Peptide Synthesis ◽  
Synthetic Peptides ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Amino Group ◽  
Efficient Synthesis ◽  
Phase Synthesis

<p>Solid phase peptide synthesis using the Fmoc/<em>t</em>-Bu strategy (SPPS-Fmoc/tBu) is the most widely used methodology for obtaining synthetic peptides. In this paper, we evaluate the viability of using 4-methylpiperidine as a reagent for deprotection of the amino acid alpha amino group in SPPS-Fmoc/tBu. For this purpose, the peptide (RRWQWRMKKLG) was simultaneously synthesized using 4-methylpiperidine or piperidine for Fmoc removal reagent. The obtained products had similar purities and yields. Finally, 21 peptides were synthesized using 4-methylpiperidine. Our results suggest that is possible to obtain synthetic peptides efficiently by the strategy SPPS-Fmoc/tBu when 4-methylpiperidine was used as reagent to remove Fmoc groups N-alpha protected amino acids.</p>

The Boc/Solid Phase Synthesis of Glu-Abu(P)-Leu

1992 ◽  
Vol 45 (10) ◽  
pp. 1765 ◽  
Author(s):  
JW Perich ◽  
EC Reynolds
Keyword(s):  
Amino Acids ◽  
Peptide Synthesis ◽  
Trifluoroacetic Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Hydrogen Bromide ◽  
Solid Phase Peptide Synthesis ◽  
Polymer Support ◽  
Methyl Groups ◽  
Phase Synthesis

The synthesis of the 4-phosphono-2-aminobutanoyl-containing tripeptide , H- Glu -Abu(P)- Leu-OH.CF3C02H was accomplished by the use of Boc-Abu(PO3Me2)-OH in Boc /solid phase peptide synthesis. Peptide synthesis was performed by using Boc-Leu-polystyrene as the polymer support with the peptide assembled by the use of 1H-benzotriazol-1-yloxytris(pyrro1idin-1-yl) phosphonium hexafluorophosphate ( PyBOPR ) for the coupling of Boc amino acids and 50% CF3C02H/CH2C12 for cleavage of the Boc group from the Boc -peptide after each coupling cycle. The protected peptide was cleaved from the polymer support by hydrogen bromide in trifluoroacetic acid and final cleavage of the methyl groups from Glu-Abu(PO2Me2)-Leu was effected by silylitic treatment with 30% bromotrimethylsilane in acetonitrile.

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