Nucleoside dimers analogs containing floxuridine and thymidine with unnatural linker groups: synthesis and cancer line studies. Part III

Anionic Olefin Metathesis Catalysts Enable Modification of Unprotected Biomolecules in Water

Stability problems have limited the uptake of cationic olefin metathesis catalysts in chemical biology. Described herein are anionic catalysts that improve water-solubility, robustness, and compatibility with biomolecules such as DNA. A sulfonate tag is installed on the cyclic (alkyl)(amino) carbene (CAAC) ligand platform, chosen for resistance to degradation by nucleophiles, base, water, and β-elimination. Hoveyda-Grubbs catalysts bearing the sulfonated CAAC ligands deliver record productivity in metathesis of unprotected carbohydrates and nucleosides at neutral pH. Decomposed catalyst has negligible impact on metathesis selectivity, whereas N-heterocyclic carbene (NHC) catalysts degrade rapidly in water and cause extensive C=C migration.

Triazole-Modified Nucleic Acids for the Application in Bioorganic and Medicinal Chemistry

This review covers studies which exploit triazole-modified nucleic acids in the range of chemistry and biology to medicine. The 1,2,3-triazole unit, which is obtained via click chemistry approach, shows valuable and unique properties. For example, it does not occur in nature, constitutes an additional pharmacophore with attractive properties being resistant to hydrolysis and other reactions at physiological pH, exhibits biological activity (i.e., antibacterial, antitumor, and antiviral), and can be considered as a rigid mimetic of amide linkage. Herein, it is presented a whole area of useful artificial compounds, from the clickable monomers and dimers to modified oligonucleotides, in the field of nucleic acids sciences. Such modifications of internucleotide linkages are designed to increase the hybridization binding affinity toward native DNA or RNA, to enhance resistance to nucleases, and to improve ability to penetrate cell membranes. The insertion of an artificial backbone is used for understanding effects of chemically modified oligonucleotides, and their potential usefulness in therapeutic applications. We describe the state-of-the-art knowledge on their implications for synthetic genes and other large modified DNA and RNA constructs including non-coding RNAs.

Recent Advances in the Use of the Dimerization Strategy as a Means to Increase the Biological Potential of Natural or Synthetic Molecules

The design of C₂-symmetric biologically active molecules is a subject of interest to the scientific community. It provides the possibility of discovering medicine with higher biological potential than the parent drugs. Such molecules are generally produced by classic chemistry, considering the shortness of reaction sequence and the efficacy for each step. This review describes and analyzes recent advances in the field and emphasizes selected C₂-symmetric molecules (or axial symmetric molecules) made during the last 10 years. However, the description of the dimers is contextualized by prior work allowing its development, and they are categorized by their structure and/or by their properties. Hence, this review presents dimers composed of steroids, sugars, and nucleosides; known and synthetic anticancer agents; polyphenol compounds; terpenes, known and synthetic antibacterial agents; and natural products. A special focus on the anticancer potential of the dimers transpires throughout the review, notwithstanding their structure and/or primary biological properties.

The Sulfo-Click Reaction and Dual Labeling of Nucleosides

This article contains detailed synthetic procedures for the implementation of the sulfo-click reaction to nucleoside derivatives. First, 3'-O-TBDMS-protected nucleosides are converted to their corresponding 4'-thioacid derivatives in three steps. Then, various conjugates are synthetized via a biocompatible and chemoselective coupling procedure using sulfonyl azide partners. Finally, to illustrate the potential of the sulfo-click reaction, a nucleoside bearing two orthogonal azido groups is synthesized and engaged in one-pot dual labeling through a sulfo-click/copper-catalyzed azide-alkyne cycloaddition (CuAAC) cascade. The high efficiency of the sulfo-click reaction as applied to nucleosides opens up new possibilities in the context of bioconjugation. © 2020 Wiley Periodicals LLC. Basic Protocol 1: General protocol for the synthesis of 4'-thioacid-nucleoside derivatives Basic Protocol 2: Implementation of the sulfo-click reaction Basic Protocol 3: Synthesis of 3'-azido-4'-(carboxamido)ethane-sulfonyl azide-3'-deoxythymidine Basic Protocol 4: Detailed synthetic procedure for one-pot double-click conjugations.