Four new side-chain amide (2 and 3) and hydroxamate (4 and 5) analogs of the hormone calcitriol (1) have been prepared. Even though lacking the 25-OH group characteristic of natural calcitriol (1), analogs 2-4 are as antiproliferative in vitro as calcitriol (1) but are 20-40 times less calciuric in vivo than calcitriol (1).
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http://dx.doi.org/10.1016/j.bmc.2006.05.050 | DOI Listing |
Many protein bioconjugation strategies focus on the modification of lysine residues owing to the nucleophilicity of their amine side-chain, the generally high abundance of lysine residues on a protein's surface and the ability to form robustly stable amide-based bioconjugates. However, the plethora of solvent accessible lysine residues, which often have similar reactivity, is a key inherent issue when searching for regioselectivity and/or controlled loading of an entity. A relevant example is the modification of antibodies and/or antibody fragments, whose conjugates offer potential for a wide variety of applications.
View Article and Find Full Text PDFSmall
January 2025
Xi'an Key Laboratory of Functional Organic Porous Materials, Key Laboratory of Special Functional and Smart Polymer Materials of Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, 710129, P. R. China.
Self-assembly in supramolecular chemistry is crucial for nanostructure creation but faces challenges like slow speeds and lack of reversibility. In this study, a novel comb-like polymer poly(amide sulfide) (PAS) based on thiolactone chemistry is reported, which rapidly self-assemble into stable nanofibers, offering excellent robustness and reversibility in the self-assembled structure. The PAS backbone contains pairs of amide bonds, each linked to an alkyl side chain in a controlled 2:1 ratio.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Department of Physics and Astronomy, Aarhus University, Aarhus 8000, Denmark.
J Am Chem Soc
January 2025
Department of Chemistry, Seoul National University, Seoul 08826, Korea.
Sequence-defined polymers composed of a large pool of chemically distinct monomers (SDPs) have been pursued to achieve the structural and functional precisions exhibited by biopolymers in nonbiological environments. In contrast to the incremental growth of SDPs by sequential addition of individual monomers, the iterative exponential growth (IEG) method allows the synthesis of high molecular-weight SDPs, but their sequences have been composed mostly of binary monomers. Consequently, achieving high molecular-weight SDPs built with a large pool of monomers remains a challenge.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Department of Chemistry, New York University, New York, New York 10003, USA.
We report the use of unprotected amino acids as submonomer reagents in the solid-phase synthesis of -substituted glycine peptoid oligomers. Subsequent coupling of an amine, alcohol, or thiol to the free carboxylate of the incorporated amino acid provides access to peptoids bearing amides, esters, and thioesters as side chain pendant groups and permits further elongation of the peptoid backbone. The palette of readily obtained building blocks suitable for solid-phase peptoid synthesis is substantially expanded through this protocol, further enhancing the chemical diversity and potential applications of sequence-specific peptoid oligomers.
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