Anodic oxidation of N-acyl and N-alkoxycarbonyl dipeptide esters as a key step for the formation of chiral heterocyclic synthetic building blocks
摘要:
The anodic oxidation of N-protected dipeptide esters using chloride as a redox catalyst can be performed regioselectively at the C-terminal amino acid. With methanol as solvent, glycine as the C-terminal, and L-valine or L-proline as N-terminal amino acid methoxylation at the glycine residue takes place. Deprotection of this product leads to the (3S,6RS)-6-methoxy-2,5-piperazinedione(3) which can be applied as a chiral cationic glycine equivalent. The exchange of the methoxy group by C-nucleophiles takes place with high trans-diastereoselectivity under steric control by the substituent in 3-position. With branched amino acids at the C-terminus of the dipeptide ester the anodic oxidation in acetonitrile/methanol (95:5) as solvent with tetraethylammonium chloride as supporting electrolyte and redox catalyst leads to methyl imidazolidin-4-one-2-carboxylates. The cyclization takes place via the intermediate formation of the N-acylimino ester of the C-terminal amino acid.
A green protocol for peptide bond formation in WEB
作者:Manashjyoti Konwar、Abdul Aziz Ali、Diganta Sarma
DOI:10.1016/j.tetlet.2016.04.041
日期:2016.5
A simple, efficient, and environmentally friendly approach has been developed for the synthesis of peptides in aqueous medium. In this work, peptides are easily synthesized in water extract of banana (WEB)/ethylene glycol and without using external base under mild condition.
A potential greener protocol for peptide coupling reactions using recyclable/reusable ionic liquid [ $$\hbox {C}_{4}\hbox {-DABCO}][\hbox {N(CN)}_{2}$$ C 4 -DABCO ] [ N(CN) 2 ]
作者:Manashjyoti Konwar、Nageshwar D Khupse、Prakash J Saikia、Diganta Sarma
DOI:10.1007/s12039-018-1461-0
日期:2018.5
systems. Here, we carried out the peptide bond formation reaction in one of the environmentally secure solvents, ‘ionic liquids’ in the presence of coupling reagent and in the absence of external base at room temperature, affording dipeptides in good to excellent yields. GRAPHICAL ABSTRACTSYNOPSIS We carried out the peptide bond formation reaction in ionic liquids in the presence of a coupling reagent
development of the Ir(III)-catalyzed direct C-H amidation of arenes and alkenes using acyl azides as the nitrogen source. This procedure utilizes an in situ generated cationic half-sandwich iridium complex as a catalyst. The reaction takes place under very mild conditions, and a broad range of sp(2) C-H bonds of chelate group-containing arenes and olefins are smoothly amidated with acyl azides without the intervention
Chemoselective Peptide Backbone Diversification and Bioorthogonal Ligation by Ruthenium‐Catalyzed C−H Activation/Annulation
作者:Liangliang Song、Gerardo M. Ojeda‐Carralero、Divyaakshar Parmar、David A. González‐Martínez、Luc Van Meervelt、Johan Van der Eycken、Jan Goeman、Daniel G. Rivera、Erik V. Van der Eycken
DOI:10.1002/adsc.202100323
日期:2021.7
The field of peptide derivatization by metal-catalyzed C−H activation has been mostly directed to modify the side chains, but poor attention has been given to the peptide backbone. Here we report a ruthenium-catalyzed C−H activation/annulation process that can chemoselectively modify the peptide backbone producing functionalized isoquinolone scaffolds with high regioselectivity in a rapid and step-economical
A mild and simple method for the selective introduction of carbinol side chains onto glycine residues in peptides is presented as a potential route for the preparation of peptide libraries. A series of di- and tripeptides, as well as one tetrapeptide, each possessing one glycine residue, were first selectively functionalized at this amino acid unit by a two-step sequence involving bromination with