Alkyl Addition Reaction of Pyrimidine 2’-ketonucleosides: Synthesis of 2’-branched-chain Sugar Pyrimidine Nucleosides (nucleosides And Nucleotides. LXXXI1))

Abstract

The reaction of 4-ethoxy-1-(3,5-O-tetraisopropyldisiloxanyl-l,3-diyl-β-D-erthro-pentofuran- 2-ulosyl)-2(lH)-pyrimidinone (11) with various organometallic reagents yielded corresponding 2’ branched-chain sugar pyrimidine nucleosides. Only in the reactions with MeMgBr and EtMgBr was the more hindered β-attack observed to afford the 2’-alkyl ribofuranosides (13a, b). In the reaction of 11 with MeLi, Me3Al, or PhMgBr, 2’-methyl or phenyl arabinosides (12a, b, c) were obtained stereoselectively. Conversion of these pyrimidine nucleosides into cytosine derivatives is also described and their antileukemic and antiviral activities are discussed. © 1988, The Pharmaceutical Society of Japan. All rights reserved.