Synthesis and properties of (2´S)- and (2´R)-2´-deoxy-2´-C-methyl oligonucleotides

The synthesis of (2′S)- and (2′R)-2′-deoxy-2′-C-methyl-N3-(4-t-butylbenzoyl) uridine, (2′S)-2′-deoxy-2′-C-methyluridine and (2′S)-2′-deoxy-2′-C-methyl-N4-isobutyryl cytidine building blocks are here described. The preparation of oligonucleotides carrying these monomers in all positions but 3′-end is presented and the binding affinity between these new fragments and the complementary DNA and RNA sequences is also assessed. (2′R) substituted oligonucleotides did not hybridize with either the complementary DNA or RNA sequences. However, the first derivative of melting curves of hybrids containing (2′S) modified oligonucleotides indicated melting transitions.