2'-O-[2-(2,3-Diacetoxypropyl)amino-2-oxoethyl]uridine 3'-phosphoramidite was prepared and used in solid-phase synthesis to obtain oligonucleotides containing a 1,2-diol group, which may then be converted into a 2'-aldehyde group. The oligonucleotides were conjugated efficiently to various molecules by chemoselective ligation that involves an addition-elimination reaction between the 2'-aldehyde group and a suitable nucleophile, such as a hydrazine, a O-alkylhydroxylamine or an 1,2-aminothiol. The method was applied successfully to the conjugation of peptides to oligonucleotides at the 2'-position.
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http://dx.doi.org/10.1016/j.bmc.2005.05.024 | DOI Listing |
Bioorg Chem
January 2025
School of Pharmaceutical Science and Technology (SPST), Tianjin University, Tianjin 300072, PR China; Singapore Eye Research Institute (SERI), The Academia, 20 College Road, Discovery Tower, Singapore 169856, Singapore.
We have successfully designed and assembled a 66-member library of protein tyrosine phosphatases (PTP) inhibitor candidates using α-ketoacid-hydroxylamine (KAHA) ligation. Subsequent in situ enzymatic screening revealed a potent hit (IC = 1.67 μM) against PTP1B, which displayed 6.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Basic Education, Shanxi Agricultural University, Jinzhong, Shanxi 030801, P. R. China.
DFT calculations have been performed to gain insight into the mechanism of hydrocarbonylation of olefins and the origin of regio- and chemoselectivity. It is shown that the most feasible mechanism involves five steps: (i) decomposition of acetic formic anhydride, (ii) hydropalladation of olefins, (iii) CO migratory insertion, (iv) iodide-assisted acetate-formate exchange, and (v) formylation or carboxylation. Importantly, carboxylation proceeds via the decomposition of anhydride, followed by reductive elimination instead of direct hydrolysis of anhydride.
View Article and Find Full Text PDFPhys Chem Chem Phys
November 2024
Key Laboratory of Chemical Additives for China National Light Industry, College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an 710021, P. R. China.
The mechanism, regioselectivity, and chemoselectivity in a gold-catalyzed oxidative cyclization of diynones with alcohols to give furan-3-carboxylate derivatives were explored by density functional theory (DFT). The obtained results revealed that the first step of the global reaction involves a nucleophilic attack of a pyridine--oxide derivative on the catalyst-ligated diynone, forming a vinyl intermediate that can isomerize to an α,α'-dioxo gold carbene upon the cleavage of the N-O bond. In the second step, a nucleophilic addition is also completed pyridine--oxide instead of an alcohol proposed in the experiment.
View Article and Find Full Text PDFACS Macro Lett
November 2024
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States.
Org Lett
November 2024
Institute of Translational Medicine, National Facility for Translational Medicine (Shanghai), Shanghai Jiao Tong University, Shanghai 200240, China.
Here we report the modular synthesis of 1,5-disubstituted tetrazoles using two highly chemoselective reactions, ligations of -fluorosulfurylamidines with amines and diazotransfer reactions between FSON and -monosubstituted amidines, respectively. Enabled by sulfur(VI) fluoride exchange (SuFEx) click chemistry, we have successfully synthesized a series of -fluorosulfurylamidines and identified them as stable and scalable organic synthons. We then discover that -fluorosulfurylamidines react selectively toward a series of aliphatic amines, resulting in the formation of -monosubstituted amidines that can react further with FSON to deliver 1,5-disubstituted tetrazoles.
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