The N-arylation of the side chain of histidine by using triarylbismuthines is reported. The reaction is promoted by copper(II) acetate in dichloromethane at 40 °C under oxygen in the presence of diisopropylethylamine and 1,10-phenanthroline and allows the transfer of aryl groups with substituents at any position of the aromatic ring. The reaction shows excellent functional group tolerance and is applicable to dipeptides where the histidine is located at the N terminus. A histidine-guided backbone N-H arylation was observed in dipeptides where the histidine occupies the C terminus.
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Bull Math Biol
January 2025
Department of Mathematics, Vivekananda College, Kolkata, West Bengal, 700063, India.
The extinction of species is a major threat to the biodiversity. Allee effects are strongly linked to population extinction vulnerability. Emerging ecological evidence from numerous ecosystems reveals that the Allee effect, which is brought on by two or more processes, can work on a single species concurrently.
View Article and Find Full Text PDFAnimal Model Exp Med
January 2025
College of Traditional Chinese Medicine and Food Engineering, Shanxi University of Chinese Medicine, Taiyuan, China.
Background: Indole phytoalexins, plant-derived compounds present in cruciferous vegetables, have demonstrated anticancer properties. Brassinin (BSN), derived from Brassica campestris L. var.
View Article and Find Full Text PDFMol Phys
March 2024
Department of Physics, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States.
The stability of proteins and small peptides depends on the way they interact with the surrounding water molecules. For small peptides, such as -helical polyalanine (polyALA), water molecules can weaken the intramolecular hydrogen-bonds (HB) formed between the peptide backbone O and NH groups which are responsible for the -helix structure. Here, we perform molecular dynamics simulations to study the hydration of polyALA, polyserine (polySER), and other homopolymer peptide -helices at different temperatures and pressures.
View Article and Find Full Text PDFChemistry
January 2025
Middle East Technical University: Orta Dogu Teknik Universitesi, Chemistry, Universiteler Mah., 06800, Cankaya, TURKEY.
This study introduces a new donor group capable of activating click-type [2+2] cycloaddition-retroelectrocyclizations, generally known for their limited scope. Target chromophores were synthesized using isocyanate-free urethane synthesis. The developed synthetic method allows for the tuning of the optical properties of the chromophores by modifying the donor groups, the acceptor units, and the side chains.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Pharmaceutical and Chemical Engineering & Institute for Advanced Studies, Taizhou University, 1139 Shifu Avenue, Taizhou 318000, Zhejiang,China.
We report an enhanced recognition and redox-responsive reversible host-guest system based on ester-bearing calix[]phenoxazines. The carbonyl groups, oriented toward the cavity, act as the extra binding sites to enhance the binding affinity, which is confirmed by NMR and FTIR experiments and single-crystal structure analysis. Due to the oxidizable nature of calix[]phenoxazine, a redox-controlled reversible response is established.
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