Synthesis of novel DNA and RNA nucleoside analogs

These studies were directed towards the syntheses of modified nucleosides which can be used as biological probes. 7-methyl-1-beta-D-deoxyribofuranosyl-1 H-imidazo[4,5-c]pyridin-4-ylamine or 3-methyl-3-deaza deoxyadenosine (3mddA) was synthesized in 9 steps starting from 3-picoline N-oxide. Along with 3mddA were synthesized several other nucleoside analogs with an imidazo[5,6-d]pyridine skeleton.;5-iodocytidine phosphoramidite was synthesized as a tool to solve the phase problem of oligoribonucleotides by the heavy atom method. This heavy atom cytidine derivative was incorporated into four oligoribonucleotides. Site specific incorporation of 5-iodocytidine shows promise for solving the X-ray crystallographic phase problem of RNAs.