Studies on Transfer Ribonucleic Acids and Related Compounds. XLI. Synthesis of tRNA Fragments containing Modified Nucleosides

Abstract

tRNA fragments containing modified nucleosides have been synthesized either by condensation of nucleotides containing a modified base or by modification of oligonucleotides. Ribothymidine 3'-phosphate was prepared by condensation of the silylated base with protected D-ribose followed by phosphorylation. Ribothymidine-containing trimer, T-Ψ-C, was synthesized by the phosphodiester method. A ribothymidine-containing hexamer T-U-C-A-A-A and a 2'-O-methylcytidine containing hexamer C-G-G-G-Cm-Up were synthesized by the phosphotriester method. A dihydrouridine-containing trimer D-A-G and a 7-methylguanosine-containing trimer m⁷G-U-C were obtained by modification of the trimers by reduction and methylation, respectively.