Competitive formation of 10- and 7-membered hydrogen-bonded rings of proline-containing model peptides
作者:Yusuke Jin、Kenji Tonan、Shun-ichi Ikawa
DOI:10.1016/s1386-1425(02)00031-8
日期:2002.10
N-tert-butoxycarbonyl-prolyl-Xaa-NHCH3 [Xaa = Gly (glycyl), Ala (alanyl), Phe (phenylalanyl), Leu (leucyl), Ile (isoleucyl), and Val (valyl)] were studied by protonnuclearmagneticresonance and infrared spectroscopy. Variation of chemicalshifts of amide protons with composition change of DMSO-d6/CDCl3 mixed solvents were found to be a good measure of intramolecular hydrogen bonding of peptides in CDCl3
Peptide Syntheses with theN-PChd Protective Group Synthesis of the Hydrophobic Segment 14–20 L-Ala-Leu-Ile-Leu-Leu-Ala-Gln of Human Lymphoblastoid Interferon
Amino acidesters were transformed in 59–97% yields into N-(3,5-di-tert-butyl-4-oxo-1-phenyl-2,5-cyclohexadienyl)amino acidesters (N-PChd amino acidesters) 8via anodic oxidation in the presence of 2,6-di-tert-butyl-4-phenylphenol (1a). Hydrolysis of 8 lead to the corresponding N-PChd amino acids 9. The novel PChd protectivegroup is stable towards basic reagents, it can be removed by hydrogenation
Studies on Optically Active Amino Acids. V. Synthesis of Optically Active α-Aminoalcohols by the Reduction of α-Amino Acid Esters with Sodium Borohydride
A facile reduction of optically active α-amino acid esters and their hydrochlorides took place with sodium borohydride in ethanol or aqueous ethanol to give the corresponding optically active α-aminoalcohols in fair yields. The reaction conditions were investigated.
The invention provides novel nucleoside compounds of formula I wherein R
1
, R
2a
, R
2b
, R
3
, R
4
, R
5
, R
6
, R
8a
, R
9
and R
10
are as defined herein which are useful for the treatment of Hepatitis C Virus (HCV) mediated diseases. The invention further provides methods for treatment or prophylaxis of HCV mediated diseases with compounds of formula I and pharmaceutical compositions comprising these compounds,
Site-Selective Modification of α-Amino Acids and Oligopeptides via Native Amine-Directed γ-C(sp<sup>3</sup>)-H Arylation
作者:Feipeng Yuan、Zhen-Lin Hou、Pranab K. Pramanick、Bo Yao
DOI:10.1021/acs.orglett.9b03607
日期:2019.12.6
Site-selective modification of chemically and biologically valuable α-aminoacids and peptides is of great importance for biochemical study and pharmaceutical development. Few methods based on remote C(sp3)-H functionalization of aliphatic side-chains of peptides has been disclosed in recent years. In this report, we developed a novel approach for γ-C(sp3)-H and γ-/δ-C(sp2)-H arylation of α-aminoacids with