Bioorthogonal chemistry has become one of the main driving forces in current chemical biology, inspiring the search for novel biocompatible chemospecific reactions for the past decade. Alongside the well-established labeling strategies that originated the bioorthogonal paradigm, we have recently proposed the use of heterogeneous palladium chemistry and bioorthogonal Pd(0)-labile prodrugs to develop spatially targeted therapies. Herein, we report the generation of biologically inert precursors of cytotoxic gemcitabine by introducing Pd(0)-cleavable groups in positions that are mechanistically relevant for gemcitabine's pharmacological activity. Cell viability studies in pancreatic cancer cells showed that carbamate functionalization of the 4-amino group of gemcitabine significantly reduced (>23-fold) the prodrugs' cytotoxicity. The N-propargyloxycarbonyl (N-Poc) promoiety displayed the highest sensitivity to heterogeneous palladium catalysis under biocompatible conditions, with a reaction half-life of less than 6 h. Zebrafish studies with allyl, propargyl, and benzyl carbamate-protected rhodamines confirmed N-Poc as the most suitable masking group for implementing in vivo bioorthogonal organometallic chemistry.
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http://dx.doi.org/10.1021/jm500531z | DOI Listing |
Nano Lett
January 2025
Department of Chemistry, KAIST, Daejeon 34141, Korea.
Bicontinuous metal structures possess unique physical and chemical properties, such as efficient mass transport capability and abundant low-coordinated surface atoms, that make them highly desirable catalysts for various important chemical reactions. Here, we report a one-pot synthesis approach to fabricate bicontinuous Pd nanocubes without a sacrificial template or a dealloying process. The prepared bicontinuous Pd nanocubes have a porous structure consisting of continuous nanosized ligaments, which can enable high atom utilization efficiency and offer abundant low-coordinated surface atoms.
View Article and Find Full Text PDFChem Asian J
January 2025
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Hubei, Wuhan, 430074, 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 m g 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 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.
View Article and Find Full Text PDFCatal Sci Technol
December 2024
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern Freiestrasse 3 3012 Bern Switzerland
Even though α-arylation of ketones is attractive for direct C-H functionalization of organic substrates, the method largely relies on phosphine-ligated palladium complexes. Only recently, efforts have focused on developing nitrogen-based ligands as a more sustainable alternative to phosphines, with pyridine-functionalized pyridinium amidate (pyr-PYA) ,'-bidentate ligands displaying good selectivity and activity. Here, we report on a second generation set of catalyst precursors that feature a 5-membered N-heterocycle instead of a pyridine as chelating unit of the PYA ligand to provide less steric congestion for the rate-limiting transmetalation of the enolate.
View Article and Find Full Text PDFMolecules
December 2024
Department of Molecular and Analytical Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary.
Bimetallic PdCu nanoparticles with different Pd:Cu ratios and morphologies can be synthesized and immobilized on a variety of support materials. Accordingly, PdCu nanoparticles can be efficiently applied as heterogeneous catalysts in a large number of organic transformations including C-C coupling and cross-coupling reactions. As related to their favorable electronic and structural interactions, the catalytic performances of PdCu bimetallic nanoparticles may be superior to monometallic species.
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