A traceless approach for the solid-phase synthesis of 6-amino-1,3,5-triazine-2,4-diones is described. Reaction of resin-bound S-methylisothiourea with isocyanates yielded resin-bound iminoureas 3, which reacted with amines to afford the corresponding guanidines 4. Following intramolecular cyclizative cleavage of the resin-bound guanidines using potassium ethoxide as a base, the desired products 5 were obtained in good yields and high purities.
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Org Lett
December 2024
Biomimetic Catalysis, Catalysis Research Center, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstrasse 4, 85748 Garching, Germany.
Inspired by natural cryptic halogenation in -bond formation, this study developed a synthetic approach combining biocatalytic bromination with transition-metal-catalyzed cross-coupling. Using the cyanobacterial VHPO, a robust and sustainable bromination-arylation cascade was created. Genetic modifications allowed enzyme immobilization, enhancing the compatibility between biocatalysis and chemocatalysis.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Potsdam 14476, Germany.
Automated glycan assembly (AGA) streamlines the synthesis of complex oligosaccharides. The reducing end of the oligosaccharide serves as an attachment site to the polymer support to liberate a free reducing end or an aminopentanol for ready conjugation to carrier proteins or surfaces. The facile installation of different aglycons on oligosaccharides has not been possible via AGA until now.
View Article and Find Full Text PDFMetabolites
December 2024
Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan.
Covalent modification of proteins at specific, predetermined sites is essential for advancing biological and biopharmaceutical applications. Site-selective labeling techniques for protein modification allow us to effectively track biological function, intracellular dynamics, and localization. Despite numerous reports on modifying target proteins with functional chemical probes, unique organic reactions that achieve site-selective integration without compromising native functional properties remain a significant challenge.
View Article and Find Full Text PDFAdv Mater
December 2024
Department of Thoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China.
Ribonucleoprotein (RNP)-based CRISPR/Cas9 genome editing holds great potential for the treatment of choroidal neovascularization (CNV), which however, is challenged by the lack of efficient cytosolic protein delivery tools. Herein, reversibly-phosphorylated pro-proteins (P-proteins) with conjugated adenosine triphosphate (ATP) tags are engineered and coupled with a membrane-penetrating, guanidine-enriched, α-helical polypeptide (GP) to mediate robust and universal cytosolic delivery. GP forms salt-stable nanocomplexes (NCs) with P-proteins via electrostatic interaction and salt bridging, and the helix-assisted, strong membrane activities of GP enabled efficient cellular internalization and endolysosomal escape of NCs.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Pitaevskii BEC Center, CNR-INO and Dipartimento di Fisica, Università di Trento, Via Sommarive 14, Trento I-38123, Italy.
Nonadiabatic quantum-classical mapping approaches have significantly gained in popularity over the past several decades because they have acceptable accuracy while remaining numerically tractable even for large system sizes. In the recent few years, several novel mapping approaches have been developed that display higher accuracy than the traditional Ehrenfest method, linearized semiclassical initial value representation (LSC-IVR), and Poisson bracket mapping equation (PBME) approaches. While various benchmarks have already demonstrated the advantages and limitations of those methods, unified theoretical justifications of their short-time accuracy are still demanded.
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