title: Studies toward the oxidative and reductive activation of C-S bonds in 2'-S-aryl-2'-thiouridine derivatives.
abstract: Studies directed toward the oxidative and reductive desulfurization of readily available 2'-S-aryl-2'-thiouridine derivatives were investigated with the prospect to functionalize the C2'-position of nucleosides. The oxidative desulfurization-difluorination strategy was successful on 2-(arylthio)alkanoate surrogates, while extension of the combination of oxidants and fluoride sources was not an efficient fluorination protocol when applied to 2'-S-aryl-2'-thiouridine derivatives, resulting mainly in C5-halogenation of the pyrimidine ring and C2'-monofluorination without desulfurization. Cyclic voltammetry of 2'-arylsulfonyl-2'-deoxyuridines and their 2'-fluorinated analogues showed that cleavage of the arylsulfone moiety could occur, although at relatively high cathodic potentials. While reductive-desulfonylation of 2'-arylsulfonyl-2'-deoxyuridines with organic electron donors (OEDs) gave predominantly base-induced furan type products, chemical (OED) and electrochemical reductive-desulfonylation of the α-fluorosulfone derivatives yielded the 2'-deoxy-2'-fluorouridine and 2',3'-didehydro-2',3'-dideoxy-2'-fluorouridine derivatives. These results provided good evidence of the generation of a C2'-anion through carbon-sulfur bond cleavage, opening new horizons for the reductive-functionalization approaches in nucleosides.
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.
authors.forename: Ramanjaneyulu
authors.initials: R
authors.lastname: Rayala
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA; Aix Marseille Université, CNRS, ICR UMR 7273, 13385, Marseille Cedex 05, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Giuglio-Tonolo
authors.affiliation: Aix Marseille Université, CNRS, ICR UMR 7273, 13385, Marseille Cedex 05, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Broggi
authors.affiliation: Aix Marseille Université, CNRS, ICR UMR 7273, 13385, Marseille Cedex 05, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Terme
authors.affiliation: Aix Marseille Université, CNRS, ICR UMR 7273, 13385, Marseille Cedex 05, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Vanelle
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.
authors.forename: Patricia
authors.initials: P
authors.lastname: Theard
authors.affiliation: Université de Lyon & Université Claude Bernard Lyon 1 (UCBL), Institut de Chimie et Biochimie Moléculaires et Supramoléculaires (ICBMS) UMR CNRS-UCBL-INSALyon 5246, 43 bd du 11 Novembre 1918, Villeurbanne, France.
authors.forename: Maurice
authors.initials: M
authors.lastname: Médebielle
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.
authors.forename: Stanislaw F
authors.initials: SF
authors.lastname: Wnuk
keywords: Cyclic Voltammetry; Desulfurization-Fluorination; Fluorination; Nucleosides; Organic Electron Donors; Reductive Desulfonylation