A step-economic and one-pot access to chiral C<sup>α</sup>-tetrasubstituted α-amino acid derivatives <i>via</i> a bicyclic imidazole-catalyzed direct enantioselective <i>C</i>-acylation
Cα-Tetrasubstituted α-amino acids are ubiquitous and unique structural units in bioactive natural products and pharmaceutical compounds. The asymmetric synthesis of these molecules has attracted a lot of attention, but a more efficient method is still greatly desired. Here we describe the first sequential four-step acylation reaction for the efficientsynthesis of chiral Cα-tetrasubstituted α-amino acid derivatives
Synthesis of Histidine-Containing Oligopeptides via Histidine-Promoted Peptide Ligation
作者:Kai-Jin Huang、Yi-Chen Huang、Yuya A. Lin
DOI:10.1002/asia.201701802
日期:2018.2.16
synthesis of histidine‐containing peptides is not trivial due to the potential of imidazole sidechain of histidine to act as a nucleophile if unprotected. A peptide ligation method utilizing the imidazole sidechain of histidine has been developed. The key imidazolate intermediate that acts as an internal acyltransfercatalyst during ligation is generated by deprotonation. Transesterification with amino
Cleavable Amide Bond: Mechanistic Insight into Cleavable 4-Aminopyrazolyloxy Acetamide at Low pH
作者:Amarnath Bollu、Nagendra K. Sharma
DOI:10.1021/acs.joc.9b00535
日期:2019.5.3
The cleavage of amide bonds under mild acidic conditions is a rare chemical event. N-Acetamide bond of peptides is extremely stable even under the strongest organic acid trifluoromethanesulfonic acid. This report mechanistically describes a new cleavable amide bond in 4-aminopyrazolyloxy acetamide peptide analogues under mild acidic conditions such as trifluoroacetic acid (10–20%) or HCl (0.1–4.0 N)
Etudes de la contribution de la liaison NH...S au potentiel redox de peptides synthetiques 4Fe4S ayant une sequence caracteristique-Cys-Gly-Ala. Donnees, en particulier, sur le comportement electrochimique de modeles de P. aerogenes Fd, soit de: [Fe 4 S 4 (Z-cys-Gly-OMe) 4 ][NMe 4 ] 2 et de [Fe 4 S 4 (Z-cys-Gly-Ala-OMe) 4 ][NMe 4 ] 2
NH...S au potentiel redox de peptides synthetiques 4Fe4S ayant une 序列特征-Cys-Gly-Ala 的贡献练习曲。Donnees, en particulier, sur le comportementelectrochimique de modeles de P. aerogenes Fd, soit de: [Fe 4 S 4 (Z-cys-Gly-OMe) 4 ][NMe 4 ] 2 et de [Fe 4 S 4 (Z) -cys-Gly-Ala-OMe) 4 ][NMe 4 ] 2
“Backdoor Induction” of Chirality in Asymmetric Hydrogenation with Rhodium(I) Complexes of Amino Acid Substituted Triphenylphosphane Ligands
作者:Zoran Kokan、Srećko I. Kirin
DOI:10.1002/ejoc.201301011
日期:2013.12
one pot two step procedure for the synthesis of conjugates 5a-g bearing two different substituents is reported. The 28 prepared phosphanes 1-5 are used as monodentateligands in the rhodium(I) catalyzed hydrogenation of 2-acetamidoacrylate or (Z)-(alpha)-acetamidocinnamate. Ligand with small side chain substituents Lig-[Ala-OMe]2 1a revealed highest selectivity with up to 84 % ee. The catalysts presented