16874-18-3Relevant academic research and scientific papers
Stereocontrolled [11C]Alkylation of N-Terminal Glycine Schiff Bases To Obtain Dipeptides
Filp, Ulrike,Peko?ak, Aleksandra,Poot, Alex J.,Windhorst, Albert D.
, p. 5592 - 5596 (2017/10/13)
The use of various quaternary ammonium salts as chiral phase-transfer catalysts allowed effective and stereoselective radiochemical [11C]alkylation to obtain functionalized dipeptides. We herein report a broadly applicable procedure for the asymmetric [11C]alkylation of dipeptides to give labeled N-terminal peptides by using different [11C]alkyl halides. Contended stereoselectivities of the reactions were observed by using 11C-labeled alkyl halides, [11C]methyl iodide and [11C]benzyl iodide, and diastereomeric ratios with different specialized catalysts of 95:5 and 90:10 were achieved, respectively. Accordingly, the straightforward synthesis of enantioenriched compounds should play a vital role in peptide-based radiopharmaceutical development and positron emission tomography imaging.
A dithienylethene-based rewritable hydrogelator
Van Herpt, Jochem T.,Stuart, Marc C. A.,Browne, Wesley R.,Feringa, Ben L.
supporting information, p. 3077 - 3083 (2014/03/21)
Dithienylethene photochromic switching units have been incorporated into a hydrogelating system based on a tripeptide motif. The resulting hybrid system provided both a photochromic response and the ability to gelate water under acidic and neutral conditi
Study of intramolecular aminolysis in peptides containing N-alkylamino acids at position 2
Ryakhovsky, Vladimir V.,Ivanov, Andrey S.
supporting information; experimental part, p. 7070 - 7076 (2012/08/29)
Many peptides and proteins, containing Nα-alkylamino acids (including proline) at the second position, are prone to intramolecular aminolysis (IA) with elimination of N-terminal dipeptide sequence as 2,5-diketopiperazines (DKP). We synthesized a series of short peptides, containing N-alkylamino acids at position 2, and studied their stability in the presence of acetic acid and amines. The presence of side chains in the second and the third amino acid residues and alkylation at Nα of the third amino acid residue slowed down IA. Nα-Alkyl residue in the first amino acid residue impeded IA only in peptides, containing three or more residues. Side chains of the first amino acids did not affect significantly the cleavage rates. Acetic acid promoted IA more strongly than aqueous ammonia, while tertiary amines were less effective. Peptides with methionine-S-oxide residues were more labile than the unoxidized analogs, suggesting intramolecular assistance of the S-oxide group in aminolysis. Surprisingly, intermediate compounds of the formula Boc-Met-MeXaa-Sar-NHR underwent rapid cleavage (endopeptolysis) upon attempted acidolytic deprotection.
Solid-phase synthesis of a cyclodepsipeptide: Cotransin
Coin, Irene,Beerbaum, Monika,Schmieder, Peter,Bienert, Michael,Beyermann, Michael
supporting information; scheme or table, p. 3857 - 3860 (2009/07/09)
(Chemical Equation Presented) The first solid-phase synthesis of cotransin-a cyclic depsipeptide having high pharmacological potential-was achieved, by a proper choice of coupling reagents and use of either TBAF or DBU for Fmoc removal to suppress the otherwise dominating, sequence-derived diketopiperazine formation. Starting the assembly from C-terminal lactic acid allowed fast and epimerization-free cyclization in solution. Novel conditions for orthogonal use of the Fmoc/Bsmoc-protection system were discovered, and an unexpected nucleophilic behavior of DBU was observed.
New enzymatic protecting group techniques for peptide and carbohydrate chemistry
Waldmann, H,Heuser, A,Braun, P,Kunz, H
, p. 799 - 802 (2007/10/02)
New methods are reported to establish enzymatic techniques for the chemo- and regioselective functionalization of carbohydrates, peptides and glycoconjugates.The N-terminal deprotection of peptides is achieved via hydrolysis of phenylacetamides, employing penicillin G acylase as biocatalyst.The C-terminal carboxyl function of peptides and O-glycopeptides is liberated by the lipase-mediated hydrolysis of heptyl esters.Penicillin G acylase and citrus acetylesterase are used to effect the chemo- and regioselective removal of phenylacetyl and acetyl blocking groups, respectively from differently protected carbohydrates.
The Phenylacetyl (PhAc) Group as Enzymatically Removable Protecting Function for Peptides and Carbohydrates: Selective Deprotections with Penicillin Acylase
Waldmann, Herbert
, p. 1175 - 1180 (2007/10/02)
Using the modified carbodiimide procedure or EEDQ as coupling reagent, N-Phenylacetyl (PhAc) amino acids are condensed in good yields with amino acid methyl, benzyl, allyl, and tert-butyl esters to give totally protected dipeptides.The PhAc group is stabl
THE USE OF PENICILLIN ACYLASE FOR SELECTIVE N-TERMINAL DEPROTECTION IN PEPTIDE SYNTHESIS
Waldmann, Herbert
, p. 1131 - 1134 (2007/10/02)
Penicillin acylase from E. coli (EC 3.5.1.11) accepts a broad range of N-phenylacetyl-dipeptide esters as substrates.The enzyme hydrolyses the N-terminal protecting group selectively at room temp. and pH=8.1 without affecting the peptide- or the ester-bonds.Alternatively methyl-, benzyl-, tert-butyl and allyl esters can be cleaved chemically leaving the phenylacetamido moiety intact.
