27167-65-3

Upstream product

• 2748-02-9 L-leucine tert-butyl ester hydrochloride 
• 3401-36-3 (N-benzyloxycarbonyl)-L-alanine N-hydroxysuccinimide ester 
• 21691-53-2 L-leucine tert-butyl ester 
• 4816-87-9 Z-L-Ala carbamoylmethyl ester 
• 28819-05-8 (S)-2-benzyloxycarbonylamino-propionic acid methyl ester 
• 1142-20-7 N-Cbz-Ala 
• 203640-41-9 Z-L-Ala 2,2,2-trifluoroethyl ester 

Downstream Products

• 22849-49-6 H-Gly-L-Ala-L-Leu-OH 
• 4864-39-5 N-carbobenzoxy-L-alanyl-L-leucine methyl ester 
• 75305-96-3 N-2-Phenyl-iso-propyloxycarbonyl-S-ethylthio-cysteinyl-alanyl-leucin-tert.-butylester 
• 61878-31-7 (S)-tert-butyl 2-((S)-2-aminopropanamido)-4-methylpentanoate 

Relevant academic research and scientific papers

Stereocontrolled [11C]Alkylation of N-Terminal Glycine Schiff Bases To Obtain Dipeptides

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.

Enzymatic synthesis of activated esters and their subsequent use in enzyme-based peptide synthesis

Chemoenzymatic peptide synthesis is potentially the most cost-efficient technology for the synthesis of short and medium-sized peptides. However, there are still some limitations when challenging peptides, e.g. containing sterically demanding acyl donors, non-proteinogenic amino acids or proline residues, are to be synthesized. To remedy these limitations, special ester moieties have been used that are specifically recognized by the enzyme, e.g. guanidinophenyl, carboxamidomethyl (Cam) or trifluoroethyl (Tfe) esters, which, unfortunately, are notoriously difficult to synthesize chemically. Herein, we demonstrate that Cam and Tfe esters are very useful for Alcalase-CLEA mediated peptide synthesis using sterically demanding and non-proteinogenic acyl donors as well as poor nucleophiles, and combinations thereof. Furthermore, these esters can be efficiently synthesized by using the lipase Cal-B or Alcalase-CLEA. Finally, it is shown that the ester synthesis by Cal-B and subsequent peptide synthesis by Alcalase-CLEA can be performed simultaneously using a two-enzyme-one-pot approach with glycolamide or 2,2,2-trifluoroethanol as additive.

Fully enzymatic peptide synthesis using C-terminal tert-butyl ester interconversion

Chemoenzymatic peptide synthesis is potentially the most cost-efficient technology for the synthesis of short and medium-sized peptides with some important advantages. For instance, stoichiometric amounts of expensive coupling reagents are not required an

Carbohydrate Protease Conjugates: Stabilized Proteases for Peptide Synthesis

The synthesis of oligopeptides using stable carbohydrate protease conjugates (CPCs) was examined in acetonitrile solvent systems.CPC was used for the preparation of peptides containing histidine, phenylalanine, tyrosine, and tryptophan in the P1 position in 60-93percent yield.The CPC was used to synthesize peptides containing both hydrophilic and hydrophobic amino acids.The P2 specificity of papain for aromatic residues was utilized for the 2 + 3 coupling of Z-Tyr-Gly-OMe to H2N-Gly-Phe-Leu-OH to generate the leucine enkephalin derivative in 79percent yield.Although papain is nonspecific for the hydrolysis of N-benzyloxycarbonyl amino acid methyl esters in aqueous solution, the rates of synthesis for these derivatives with nucleophile leucine tert-butyl ester differed by nearly 2 orders of magnitude.CPC was used to prepare the aspartame precursor Z-Asp-Phe-OMe in 90percent yield.The increased stability of CPCs prepared from periodate-modified poly(2-methacrylamido-2-deoxy-D-glucose), poly(2-methacrylamido-2-deoxy-D-galactose), and poly(5-methacrylamido-5-deoxy-D-ribose), carbohydrate materials designed to increase the aldehyde concentration in aqueous solution, suggests that the stability of CPCs is directly related to the aldehyde concentration of the carbohydrate material.Periodate oxidation of poly(2-methacrylamido-2-deoxy-D-glucose) followed by covalent attachment to α-chymotrypsin gave a CPC with catalytic activity in potassium phosphate buffer at 90 deg C for 2 h.

On the Use of Carboxamidomethyl Esters in the Protease-Catalyzed Peptide Synthesis

Carboxyamidomethyl esters (CAM esters) of Z-and Boc-protected alanine and phenylalanine were prepared in order to investigate their usefulness as substrates for α-chymotrypsin- and papain-catalyzed hydrolysis and peptide synthesis reactions.The easy removal of the CAM-C-protecting group under mild conditions and dependent on the enzyme specificity was demonstrated.Examples are given for the protease-catalyzed synthesis of various peptide derivatives using CAM esters as C- and N-components in aqueous-organic media.Comparatively short reaction times were observed. - Key words: Carboxyamidomethyl ester as C-protecting group; Enzymatic deprotection; Peptide synthesis; α-Chymotrypsin- and Papain-catalyzed peptide bond formation

Amino Acids and Peptides. XXX. Phosphorus in Organic Synthesis. XVII. Application of Diphenyl Phosphorazidate (DPPA) and Diethyl Phosphorocyanidate (DEPC) to Solid-phase Peptide Synthesis

Two coupling reagents for peptide synthesis, diphenyl phosphorazidate (DPPA) and diethyl phosphorocyanidate (DEPC), were tested using the solid-phase method.The reactivities of DPPA and DEPC were examined by coupling Boc-Ile with Gly-resin.In a comparison

Selectively S-Protected Cysteine Peptides. IV. Synthesis of Cysteine Peptides Using the S-Ethylthio Protecting Group. II

Studying the problems of the selective sulphur protection in cysteine peptides, a model octapeptide from the sheep insulin A-chain was prepared by conventional synthesis using the S-ethylthio and the S-diphenylmethyl group.As consequence of the small acid