scholarly journals Synthesis of functionalised β-keto amides by aminoacylation/domino fragmentation of β-enamino amides

2018 ◽  
Vol 14 ◽  
pp. 2602-2606 ◽  
Author(s):  
Pavel Yanev ◽  
Plamen Angelov
Keyword(s):  
Amino Acids ◽  
Side Chain ◽  
Amino Group ◽  
Acylation Reactions

Ethylenediamine-derived β-enamino amides are used as equivalents of amide enolate synthons in C-acylation reactions with N-protected amino acids. Domino fragmentation of the obtained intermediates leads to functionalised β-keto amides, bearing a protected amino group in their side chain.

Specificity of the transport system for neutral amino acids in the hamster intestine

1962 ◽  
Vol 202 (5) ◽  
pp. 919-925 ◽  
Author(s):  
Edmund C. C. Lin ◽  
Hiroshi Hagihira ◽  
T. Hastings Wilson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transport System ◽  
Side Chain ◽  
Carboxyl Group ◽  
Amino Group ◽  
Methyl Group ◽  
Neutral Amino Acids ◽  
Active Transport System ◽  
Everted Sacs

The specificity of the active transport system for neutral amino acids has been studied with everted sacs of hamster intestine. Amino acids with modifications or replacements of the carboxyl, amino, or α-hydrogen groups were poorly transported and were poor inhibitors of the transport of other l-amino acids. The carboxyl group must remain free, the amino group must not be in the tertiary or quaternary state, and the α-hydrogen can not be replaced by a methyl group without serious effect on the transport rate. It was concluded that the l-amino acids were distinguished from the d-isomers by the interaction of the carrier with the carboxyl group, the amino group, and the α-hydrogen. The side chain of the amino acid must be nonpolar but there is relatively little restriction on its structure.

Reaction of Alantolactone, an Allergenic Sesquiterpene Lactone, with some Amino Acids. Resultant Loss of Immunologic Reactivity

1974 ◽  
Vol 52 (7) ◽  
pp. 575-581 ◽  
Author(s):  
G. Dupuis ◽  
J. C. Mitchell ◽  
G. H. N. Towers
Keyword(s):  
Amino Acids ◽  
Contact Dermatitis ◽  
Sesquiterpene Lactone ◽  
Sesquiterpene Lactones ◽  
Sulfhydryl Group ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Amino Group ◽  
Michael Type Addition ◽  
Methylene Group

A study of the reaction of a hapten, alantolactone, with some amino acids is reported. Previously, we have reported than an α-methylene group attached to the γ-lactone is the immunologic requisite of alantolactone and some other sesquiterpene lactones. Such a group is known to be capable of undergoing "Michael-type addition" with the sulfhydryl group of cysteine. We confirm this finding and report that alantolactone can also undergo addition with the imidazole group of histidine and with the ε-amino group of lysine, but not with the guanido group of arginine, the hydroxyl group of serine, or the thio ether function of methionine. We selected these amino acids for further study because of their nucleophilic side chain. Samples of alantolactone that have undergone such addition no longer produce allergic eczematous contact dermatitis, as measured by patch test.

Succinimidyl esters of fatty acids for amino acid acylations

1976 ◽  
Vol 54 (5) ◽  
pp. 733-737 ◽  
Author(s):  
Alenka Paquet
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Side Chain ◽  
Amino Acid Esters ◽  
Amino Group ◽  
Acyl Chlorides ◽  
Hydroxysuccinimide Esters ◽  
Acid Esters

Fatty acid N-hydroxysuccinimide esters have been prepared from the thallium(I) salt of N-hydroxysuccinimide and the corresponding acyl chlorides in essentially quantitative yields. These active esters were used for acylation of amino acid esters in organic solvents, or of free amino acids in aqueous medium. The title compounds were found to be selective towards the side chain amino group of lysine. An efficient preparation of ε-N-benzyloxycarbonyl-L-lysine using benzyl succinimidyl carbonate is described.

Reaction of amino acids with guanidinating agents

1970 ◽  
Vol 48 (11) ◽  
pp. 1189-1191 ◽  
Author(s):  
Lynn C. Allen ◽  
T. Viswanatha
Keyword(s):  
Amino Acids ◽  
Side Chain ◽  
Amino Group ◽  
Aliphatic Side Chain

The reaction of amino acids with three guanidinating agents, viz. 2-methylpseudourea, 2-methyl-2-thiopseudourea, and guanyl-3,5-dimethylpyrazole, was investigated. The α-amino group of amino acids with an aliphatic side chain was readily convertible to the guanido group. However, the α-amino group of other amino acids was found to be either refractory or slow toward such modification.

13C nuclear magnetic resonance study of cyclodipeptides containing 13C enriched hydrophobic amino acids

1980 ◽  
Vol 45 (2) ◽  
pp. 482-490 ◽  
Author(s):  
Jaroslav Vičar ◽  
François Piriou ◽  
Pierre Fromageot ◽  
Karel Bláha ◽  
Serge Fermandjian
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Nuclear Magnetic Resonance Study ◽  
Coupling Constants ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Magnetic Resonance Study ◽  
Side Chain Conformation ◽  
13C Nuclear Magnetic Resonance ◽  
Hydrophobic Amino Acids

The diastereoisomeric pairs of cyclodipeptides cis- and trans-cyclo(Ala-Ala), cyclo(Ala-Phe), cyclo(Val-Val) and cyclo(Leu-Leu) containing 85% 13C enriched amino-acid residues were synthesized and their 13C-13C coupling constants were measured. The combination of 13C-13C and 1H-1H coupling constants enabled to estimate unequivocally the side chain conformation of the valine and leucine residues.

Peptide Modifications: Versatile Tools in Peptide and Natural Product Syntheses

Synlett ◽  
2019 ◽  
Vol 30 (11) ◽  
pp. 1289-1302 ◽  
Author(s):  
Phil Servatius ◽  
Lukas Junk ◽  
Uli Kazmaier
Keyword(s):  
Amino Acids ◽  
Natural Product ◽  
Bond Activation ◽  
Bond Formation ◽  
Side Chain ◽  
Peptide Backbone ◽  
Claisen Rearrangements ◽  
The Past ◽  
Allylic Alkylations ◽  
Peptide Modifications

Peptide modifications via C–C bond formation have emerged as valuable tools for the preparation and alteration of non-proteinogenic amino acids and the corresponding peptides. Modification of glycine subunits in peptides allows for the incorporation of unusual side chains, often in a highly stereoselective manner, orchestrated by the chiral peptide backbone. Moreover, modifications of peptides are not limited to the peptidic backbone. Many side-chain modifications, not only by variation of existing functional groups, but also by C–H functionalization, have been developed over the past decade. This account highlights the synthetic contributions made by our group and others to the field of peptide modifications and their application in natural product syntheses.1 Introduction2 Peptide Backbone Modifications via Peptide Enolates2.1 Chelate Enolate Claisen Rearrangements2.2 Allylic Alkylations2.3 Miscellaneous Modifications3 Side-Chain Modifications3.1 C–H Activation3.1.1 Functionalization via Csp3–H Bond Activation3.2.2 Functionalization via Csp2–H Bond Activation3.2 On Peptide Tryptophan Syntheses4 Conclusion

Enhanced hydrate formation by natural-like hydrophobic side chain amino acids at ambient temperature: A kinetics and morphology investigation

Fuel ◽  
2021 ◽  
Vol 299 ◽  
pp. 120828
Author(s):  
Kan Jeenmuang ◽  
Chakorn Viriyakul ◽  
Katipot Inkong ◽  
Hari Prakash Veluswamy ◽  
Santi Kulprathipanja ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ambient Temperature ◽  
Hydrate Formation ◽  
Side Chain

Redesign of (R)-Omega-Transaminase and Its Application for Synthesizing Amino Acids with Bulky Side Chain

2021 ◽  
Author(s):  
Dong-Xu Jia ◽  
Chen Peng ◽  
Jun-Liang Li ◽  
Fan Wang ◽  
Zhi-Qiang Liu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Side Chain ◽  
Bulky Side Chain
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