title: Base-Modified Nucleosides: Etheno Derivatives.
abstract: This review presents synthesis and chemistry of nucleoside analogs, possessing an additional fused, heterocyclic ring of the "etheno" type, such as 1,N(6)-ethenoadenosine, 1,N(4)-ethenocytidine, 1,N(2)-ethenoguanosine, and other related derivatives. Formation of ethenonucleosides, in the presence of α-halocarbonyl reagents and their mechanism, stability, and degradation, reactions of substitution and transglycosylation, as well as their application in the nucleoside synthesis, have been described. Some of the discussed compounds may be applied as chemotherapeutic agents in antiviral and anticancer treatment, acting as pro-nucleosides of already known, biologically active nucleoside analogs.
authors.affiliation: Institute of Bioorganic Chemistry, Polish Academy of Sciences Poznan, Poland.
authors.forename: Zofia
authors.initials: Z
authors.lastname: Jahnz-Wechmann
authors.affiliation: Institute of Bioorganic Chemistry, Polish Academy of Sciences Poznan, Poland.
authors.forename: Grzegorz R
authors.initials: GR
authors.lastname: Framski
authors.affiliation: Institute of Bioorganic Chemistry, Polish Academy of Sciences Poznan, Poland.
authors.forename: Piotr A
authors.initials: PA
authors.lastname: Januszczyk
authors.affiliation: Institute of Bioorganic Chemistry, Polish Academy of Sciences Poznan, Poland.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Boryski
keywords: antiviral activity; ethenonucleosides; fused heterocycles; nucleoside analogs; tricyclic acyclovir; wyosine