Preparation of ketimine derivatives of amino acids for peptide synthesis

1974 ◽  
Vol 27 (9) ◽  
pp. 2047 ◽  
Author(s):  
B Halpern ◽  
AP Hope
Keyword(s):  
Amino Acids ◽  
Hydrogen Bond ◽  
Acid Hydrolysis ◽  
Peptide Synthesis ◽  
Room Temperature ◽  
Mild Conditions ◽  
Protein Amino Acids ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Strong Intramolecular Hydrogen Bond

Condensates of some 2-hydroxyaryl ketones with protein amino acids have been prepared. The reaction has been shown to proceed without racemization and the derivatives have been isolated as free acids. Their unusual stability is ascribed to the presence of a strong intramolecular hydrogen bond. The N-arylmethylene function is cleaved under mild conditions of acid hydrolysis. Ketimines derived from D-phenylglycine decarboxylate at room temperature.

scholarly journals On the Hydration State of Amino Acids and Their Derivatives at Different Ionization States: A Comparative Multinuclear NMR and Crystallographic Investigation

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Charalampos G. Pappas ◽  
Andreas G. Tzakos ◽  
Ioannis P. Gerothanassis
Keyword(s):  
Amino Acids ◽  
Hydrogen Bond ◽  
Relaxation Times ◽  
Carboxylate Group ◽  
Ionization State ◽  
Carboxylic Groups ◽  
Hydration Model ◽  
Structure Databases ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

2D, 13C, 14N, and 17O NMR and crystallographic data from the literature were critically evaluated in order to provide a coherent hydration model of amino acids and selected derivatives at different ionization states. 17O shielding variations, longitudinal relaxation times (T1) of 2D and 13C and line widths (Δν1/2) of 14N and 17O, may be interpreted with the hypothesis that the cationic form of amino acids is more hydrated by 1 to 3 molecules of water than the zwitterionic form. Similar behaviour was also observed for N-acetylated derivatives of amino acids. An exhaustive search in crystal structure databases demonstrates the importance of six-membered hydrogen-bonded conjugated rings of both oxygens of the α-carboxylate group with a molecule of water in the vicinity. This type of hydrogen bond mode is absent in the case of the carboxylic groups. Moreover, a considerable number of structures was identified with the propensity to form intramolecular hydrogen bond both in the carboxylic acid (NH⋯O=C) and in the carboxylate (−) ionization state. In the presence of bound molecules of water this interaction is significantly reduced in the case of the carboxylate group whereas it is statistically negligible in the carboxylic group.

(1′R,3S)-2-Oxo-1-(1′-phenylethyl)piperidine-3-carboxylic acid: a case of a very strong intramolecular hydrogen bond

2004 ◽  
Vol 60 (11) ◽  
pp. o2110-o2112
Author(s):  
Ana-María Lumbreras-García ◽  
Alberto Galindo-Guzmán ◽  
Dino Gnecco ◽  
Joel-Luis Terán ◽  
Sylvain Bernès
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Intramolecular Hydrogen Bond ◽  
Intramolecular Hydrogen ◽  
Strong Intramolecular Hydrogen Bond

Aromatic amides. IX. Temperature effects on the N.M.R. spectra of substituted acetanilides

1974 ◽  
Vol 27 (12) ◽  
pp. 2617 ◽  
Author(s):  
ID Rae
Keyword(s):  
Hydrogen Bond ◽  
Chemical Shift ◽  
Benzene Ring ◽  
Intramolecular Hydrogen Bond ◽  
Temperature Effects ◽  
Dimethyl Sulphoxide ◽  
Intramolecular Hydrogen ◽  
Strong Intramolecular Hydrogen Bond ◽  
Ortho Substituent

N.m.r. spectra have been measured for several anilides in dimethyl sulphoxide solution for temperatures in the range 40-140�. The change of the N-H chemical shift with temperature depends on the nature of the ortho substituent on the benzene ring, being least when a strong intramolecular hydrogen bond is possible between the amide N-H and the ortho substituent. For 2?-nitroanilides, the 6?- proton becomes increasingly deshielded as the temperature is raised.

Self-Assembling Functionalized Amino Acids into Unusual Shapes

2011 ◽  
Vol 1312 ◽  
Author(s):  
Justin R. Barone ◽  
Naresh K. Budhavaram ◽  
Katherine J. Harvey
Keyword(s):  
Amino Acids ◽  
Hydrogen Bond ◽  
Amino Acid ◽  
Room Temperature ◽  
Vinyl Sulfone ◽  
Ethyl Vinyl ◽  
Simple Route ◽  
Self Assembling ◽  
Component Systems ◽  
Functionalized Amino Acids

ABSTRACTMulti-component small molecule systems that are amphiphilic or that can hydrogen bond end-to-end or side-to-side have been shown to self-assemble into a variety of shapes including fibers, rods, sheets, plates, spheres, and tubes. Recently, we have identified a simple route to self-assemble the same shapes from one-component systems. The structures form by attaching ethyl vinyl sulfone (EVS) to amino acids in water at room temperature. Choice of amino acid, amount of EVS substitution, and solvent conditions determine the final shape. Functionalized amino acids spontaneously form structures like fibers, spheres, tubes, and donuts when dried from solution. Here we focus on fibers and tubes.

N-Methylamino Acids in Peptide Synthesis. II. A New Synthesis of N-Benzyloxycarbonyl, N-Methylamino Acids

1973 ◽  
Vol 51 (12) ◽  
pp. 1915-1919 ◽  
Author(s):  
John R. McDermott ◽  
N. Leo Benoiton
Keyword(s):  
Amino Acids ◽  
Methyl Iodide ◽  
Peptide Synthesis ◽  
Side Chains ◽  
Butyl Group ◽  
New Synthesis ◽  
Derivatives Of

Reaction of N-benzyloxycarbonyl derivatives of aliphatic amino acids, and threonine, aspartic, and glutamic acids whose side-chains were protected with the t-butyl group, gave the corresponding N-methylamino acid derivatives in good yields. The methionine derivative could be obtained by using only one mol of methyl iodide. Derivatives of threonine, and aspartic and glutamic acids whose side-chains were not protected could not be methylated. Analysis of the crude products of methylation in three cases showed that they contained 0–1% of racemized material.

scholarly journals The reaction of iodobenzene-p-sulphonyl chloride (pipsyl chloride) with certain amino acids and peptides, and with insulin

1967 ◽  
Vol 102 (3) ◽  
pp. 815-824 ◽  
Author(s):  
J. C. Fletcher
Keyword(s):  
Amino Acids ◽  
Thin Layer ◽  
Acid Hydrolysis ◽  
Thin Layer Chromatography ◽  
Cysteic Acid ◽  
Buffer System ◽  
The Common ◽  
Layer Chromatography ◽  
Derivatives Of

1. A system of separation using buffered Celite columns is described that enables the pipsyl derivatives of most of the common amino acids to be separated. 2. The reaction of pipsyl chloride with several amino acids not included in previous studies has been investigated. In particular, knowledge of the acid-soluble pipsyl derivatives of arginine, histidine, lysine, tyrosine and cysteic acid has been extended. 3. Reproducible factors have been obtained that enable corrections to be applied for the breakdown of pipsylamino acids on acid hydrolysis. 4. The reaction of pipsyl chloride with peptides has been studied under various conditions. 5. The extent of the reaction between pipsyl chloride and insulin depends on the nature of the solvent-buffer system, and under the best conditions so far found is about 75% complete. 6. In an Appendix, the separation of pipsylamino acids by thin-layer chromatography is described.

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