STUDIES ON SYNTHESIS AND STRUCTURE OF O-BETA-D-RIBOFURANOSYL(1''-]2')RIBONUCLEOSIDES AND OLIGONUCLEOTIDES

Minor nucleosides found in several eukaryotic initiator tRNAs(i)(Met), O-beta-D-ribofuranosyl(1''-->2')adenosine and -guanosine (Ar and Gr), as well as their pyrimidine analogues, were obtained from N-protected -tetraisopropyldisiloxane-1,3-diyl)ribonucleosides and 1-O-acetyl-2,3 ,5-tri-O-benzoyl-beta-D-ribofuranose in the presence of tin tetrachlor ide in 1,2-dichloroethane. A crystal structure has been solved for 2'- O-ribosyluridine. The 3'-phosphoramidites of protected 2'-O-ribosylrib onucleosides were prepared as the reagents for 2'-O-ribofuranosyloligo nucleotides synthesis. -Ribofuranosyl(1''-->2')adenylyl(3'-->5')guanos ine (ArpG) was obtained and its structure was analysed by NMR spectros copy.