The reaction between palladium acetate and IMES.HCl leads to the formation of a novel palladium complex. The X-ray crystal structure analysis reveals that the palladium is C(2) bound to one NHC ligand (the normal binding mode), whereas the second ligand is attached through the C(5) carbon of the second imidazolium. The metalation site on the imidazolium salt is strongly influenced by the presence of base. Furthermore, the binding mode of the NHC to Pd is shown to substantially affect the catalytic behavior of the palladium complexes in cross-coupling reactions.
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http://dx.doi.org/10.1021/ja049759r | DOI Listing |
Org Lett
January 2025
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China.
Here, we report on methods for late-stage peptide diversification through palladium-catalyzed site-selective C(sp)-H amination of tryptophan residues at the C4 position, utilizing tryptophan-amine cross-links. Our strategy enables practical access to C-N bonds, facilitating the construction of cyclopeptides via late-stage cyclodimerization of structurally complex peptides, which poses significant challenges for organic synthesis. The synthetic utility of this protocol is demonstrated through the synthesis of 30- to 38-membered macrocyclic peptides.
View Article and Find Full Text PDFChem Asian J
January 2025
Huazhong University of Science and Technology, School of Chemisry & Chemical Engineering, 1037 Luoyu Road, 430074, Wuhan, CHINA.
Using a direct knitting strategy, we successfully prepared a novel heterogeneous catalyst consisting of pyridine-bridged bis(imidazolium-2-ylidene) palladium complexes (CNC-Pd) embedded in a knitted network polymer. The resulting catalysts (HCP-CNC-Pd-d) exhibited high specific surface areas of 982 m2 g-1 with microporous and mesoporous structures. The large surface area enhances contact between the substrate and the catalytic center, while the strong chelation between CNC and the metal ion ensures the catalyst's durability.
View Article and Find Full Text PDFSmall
January 2025
Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, NMPA Key Laboratory for Research and Evaluation of Drug Metabolism, and Guangdong-Hong Kong-Macao Joint Laboratory for New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong, 510515, China.
Diabetic ulcers (DUs) are characterized by a microenvironment with high oxidative stress, high blood glucose levels, and recalcitrant bacterial infections. This microenvironment is accompanied by long-term suppression of endogenous antioxidant systems, which makes their clinical management extremely challenging. To address this issue, a hybridized novel gold-palladium (AuPd) nanoshell of the injectable/injectable hydrogel system UiO/AuPd/BNN6/PEG@Gel (UAPsBP@Gel) is developed.
View Article and Find Full Text PDFEur J Med Chem
December 2024
Departamento de Química Orgánica, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain; Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain. Electronic address:
Four photosensitizers PS1a-PS4a consisting in multicationic ruthenium(II) phthalocyanines (RuPcs) have been evaluated in photodynamic inactivation (PDI) of multiresistant microorganisms. The RuPcs, bearing from 4 to 12 terminal ammonium salts, have been designed to target the microorganisms cytoplasmic cell membrane and display high singlet oxygen quantum yields. In addition, PS3a and PS4a were conceived to exhibit multi-target localization by endowing them with amphiphilic character, using two different structural approaches.
View Article and Find Full Text PDFACS Catal
January 2025
Institute of Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg, 1, 8093 Zurich, Switzerland.
Buchwald-Hartwig (BH) aminations are crucial for synthesizing arylamine motifs in numerous bioactive molecules and fine chemicals. While homogeneous palladium complexes can be effective catalysts, their high costs and environmental impact motivate the search for alternative approaches. Heterogeneous palladium single-atom catalysts (SAC) offer promising recoverable alternatives in C-C cross-couplings.
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