Synthesis and properties of novel nucleic acid probes.

2'-O-Methyl derivatives of common ribonucleosides were prepared from appropriately protected nucleosides via the methylation of the 2'-hydroxyl groups with methyl iodide or diazomethane. These derivatives were converted into 2'-O-methylribonucleotide units and the guanosine derivative was linked to a polymer support. Thus, oligo(2'-O-methylribonucleotides) having the sequence of AmCmUmUmAmCmCmUmGm was synthesized in a stepwise manner by using the phosphotriester method. Thermal stabilities (Tm's) of the hybrid between the 2'-O-methyl ribooligomer and the complementary ribooligomer and of the related hybrids are compared. The synthesis of ribooligomer by a new approach is also described.