Amides of Amino Acids

This group was developed for the protection of primary amides of amino acids. It is introduced by amide bond formation with the benzhydrylamine. It is cleaved with 1 MSiCl4/anisole/TFA/0° or 1 MTMSOTf/thioanisole/TFA, 0°. Cleavage occurs by initial sulfoxide reduction followed by acidolysis. ... 

Amides of Amino Acids Involving the Carboxyl Group... 

G Galavema, R Corradini, A Dossena, R Marchelli. Diaminomethane dihydrochloride, a novel reagent for the synthesis of primary amides of amino acids and peptides from active esters. Int J Pept Prot Res 42, 53, 1993. 

Preliminary information useful in prodrug design has been obtained with amino acids attached to model aromatic amines. Thus, N-(naphthalen-2-yl) amides of amino acids (6.1, R=side chain of amino acid, R =H) proved to be of interest as test compounds to monitor peptidase activity such as ami-nopeptidase M (membrane alanyl aminopeptidase, microsomal aminopepti-dase, EC 3.4.11.2) [16][17], In the presence of purified rabbit kidney aminopeptidase M or human cerebrospinal fluid (CSF) aminopeptidase activity, the rate of hydrolysis decreased in the order Ala-> Leu->Arg->Glu-2-naphthyl-amide. Ala-2-naphthylamide, in particular, proved to be a good test compound, as its rate of hydrolysis was influenced by experimental conditions (preparation, inhibitors, etc.), as was the hydrolysis of a number of low-molecular-weight opioid peptides and circulating vasoactive peptides. 

Ni" forms square-planar bis-complexes with the amidate anions of L-Val, L-Phe, and L-Pro. The structure of bis(Gly)-bis(imidazole)nickel(ii) has been reported and the configuration around the metal atom is cis-O(carboxyl), cis-N(amine), cis-N(imidazole). Tetra- and penta-peptide complexes of nickel(ii) consume oxygen in neutral solutions as the metal ion catalyses peptide oxidation to give a number of products, including amides of amino-acids and peptides, oxo-acids, and C02- ... 

Simple alkyl or aryl esters Alkyl esters containing an amino or amido group, or another functionality (Acyloxy)methyl or (acyloxy)ethyl esters Esters of diacylaminopropan-2-ols N,N-Dialkyl hydroxylamino derivatives Amides of amino acids... 

Amides of amino acids or peptides Simple or structurally complex carbamates... 

Lactams are cyclic amides formed by the intramolecular amidation of amino acids. The polymerization of lactams [Eq. (10.48)]... 

Amides of amino acids (e.g., glycine), e.g., R-CO-NH-CH(R )-COOH Carrier groups linked to an amino or amido group (RR -NH)... 

Amides of amino acids react with complex hydrides resulting in reduction of the carbonyl to a methylene group. Thus, it is possible to obtain a variety of diamines (not containing a-hy-droxy groups) in ail enantionierically pure form. The amino acids generally employed are phcnylglycine1 and proline2 3. The majority of amines discussed in this section were used as the lithium salt in enantioselective deprotonation and elimination (Section C.). 

Danishefsky, I. and Siskovic, E., Conversion of carboxyl groups of mucopolysaccharides into amides of amino acid esters, Carbohydr. Res., 16,199,1971. 

Tetra- and penta-peptide complexes of Ni(II) have been shown to consume O2 in neutral solutions as the metal ion catalyzes the oxidation of the peptide to give a number of products including amides of amino acids and of peptides, 0x0 acids and CO2 [167]. A nickel cyclic amine complex has been shown to react with dioxygen [168] to give a 1 1 complex. When excess oxygen was added, attack on the ligand system occurred. 

Originally proteolytic enzymes (proteases) were studied by their ability to digest crude substrates later highly purified proteins were used. Proteins are polymers of 20 different a-amino acids in which the amino acid residues form substituted amides. Amides of amino acids are called peptides. In addition to the proteases, peptidases, enzymes capable of hydrolyzing small synthetic peptides, were found by Fisher. Considerable progress was made when Bergmann and his collaborators discovered that small synthetic substrates could also serve as substrates for proteolytic enzymes. ... 

More certain results are obtained by the interaction of the esters or amides of amino acids and tetra-O-acetylglucosyl bromide I8/1). The... 

Lactams are intramolecular amides of amino acids (especially y-, -e-amino acids) formed similarly to lactones from hydroxy acids. After hydrolysis the acid formed is identified. 

Substituted amides of amino acids are also hydrolyzed depending on die size of the substituent. The iV-methyl- or A-methoxy amides (13) are hydrolyzed stereoselectively albeit with a lower activity (Scheme 5) [23], whereas, for example, the A-benzylamide of DL-valine is not hydrolyzed [24]. 

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