Nucleoside macrocycles formed by intramolecular click reaction: efficient cyclization of pyrimidine nucleosides decorated with 5'-azido residues and 5-octadiynyl side chains

• Jiang Liu,
• Peter Leonard,
• Sebastian L. Müller,
• Constantin Daniliuc and
• Frank Seela

Beilstein J. Org. Chem. 2018, 14, 2404–2410, doi:10.3762/bjoc.14.217

• . Monomeric purine and pyrimidine nucleosides form smaller ring systems known as cyclonucleosides incorporating O, N or S-bridges within the sugar moiety or between the nucleobase and the sugar residue [6]. Macrocycles can be obtained by a variety of chemical reactions [7][8][9][10]. Often, several protection

Selectivity in C-alkylation of dianions of protected 6-methyluridine

• Ngoc Hoa Nguyen,
• Christophe Len,
• Anne-Sophie Castanet and
• Jacques Mortier

Beilstein J. Org. Chem. 2011, 7, 1228–1233, doi:10.3762/bjoc.7.143

• , Transformations intégrées de la matière renouvelable, EA 4297 UTC/ESCOM, 1 allée du réseau Jean-Marie Buckmaster, 60200 Compiègne, France 10.3762/bjoc.7.143 Abstract A regioselective synthesis of 6-ω-alkenyluridines 3, precursors of potent antiviral and antitumor cyclonucleosides 5, is described. While ω-alkenyl

• halides do not alkylate 6-lithiouridine, compounds 3 were prepared in a regioselective manner by sequential treatment of 6-methyluridine 2 with LTMP or LDA (4 equiv) in THF at −30 °C followed by alkylation with ω-alkenyl bromides. Keywords: C6-alkylation; cyclonucleosides; lithiations; 6-ω

• -alkenyluridines; Introduction Conformationally restricted C–C bridged cyclonucleosides bearing a linkage between the sugar moiety and the nucleobase, exhibit a broad spectrum of antiviral and antitumor activities [1][2][3][4]. Cyclonucleosides are excellent tools for studying the role of the conformational