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
The reaction of several α-aminoacids and peptides (containing Gly, L-Ala, L-Leu, L- or DL-Phe, and/or L- or D-Val) with air-diluted nitrogen oxides has been studied to roughly mimic the N-nitrosation of peptide bonds that the contaminated urban air might produce in pulmonary tissues. Most N-protected α-aminoacids give practically quantitative yields of N-nitroso derivatives. N-Protected dipeptides
已经研究了几种α-氨基酸和多肽(包含Gly,L-Ala,L-Leu,L-或DL-Phe和/或L-或D-Val)与空气稀释的氮氧化物的反应模拟被污染的城市空气可能在肺组织中产生的肽键的N-亚硝化。大多数N-保护的α-氨基酸可提供定量的N-亚硝基衍生物。受N保护的二肽提供二亚硝化肽,二亚硝化化合物和单亚硝化化合物的混合物,选择性单亚硝化产物,或根本不发生反应,这主要取决于空间效应。对于一些更高的肽,观察到相同的趋势。保留了原料的手性的(多)亚硝化肽的特征是1 H和13在温和的条件下,经吡咯烷和氨基酯裂解,得到13 C NMR光谱,得到(新的)酰胺或肽以及重氮衍生物。
Amino-acids and peptides. Part XXV. The mechanism of the base-catalysed racemisation of the p-nitrophenyl esters of acylpeptides
作者:I. Antonovics、G. T. Young
DOI:10.1039/j39670000595
日期:——
“direct exchange” mechanism of racemisation and that through the oxazolone, and it is concluded that such racemisation proceeds through the intermediate formation, racemisation, and coupling of the corresponding oxazolone. Evidence is also given that the conversion of benzyloxycarbonylglycyl-L-phenylalanine into its p-nitrophenyl ester by means of diphenyl-keten is accompanied by racemisation.
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
Considering that the amide NH groups are neither protected nor deprotonated, reductive samariation in the presence of a carbonyl substrate is a remarkably efficient method for the formation of a C-C bond. This was shown for a series of dipeptides and a tripeptide [Eq. (a)]. For the latter the product was obtained in a good yield of 50 %, despite the presence of three amide protons.