Cyclic imidazole compounds having relatively low hydrogen content and relatively high nitrogen content and polymers and copolymers formed therefrom

In a method for the synthesis of oligonucleotides comprising the steps of:

• a) reacting a 5′-protected monomer unit with an oligonucleotide unit in the presence of a coupling agent to form a reaction mixture containing a product, said product of said reaction being a 5′-protected oligonucleotide having its length increased by joining said monomer unit to said oligonucleotide unit;
• and
• b) separating the product from the unreacted starting material, unreacted 5′-protected monomer unit, side products, and reagent;
• the improvement comprising:
• said coupling agent being a polymer consisting of cyclic imidazole units having nitrogen at the 1 and 3 positions;
• a carbon at each of the 2, 4 and 5 positions;
• and radical substituents G1 and G2 carried at respective said 4 and 5 positions, where G1 and G2 are each independently selected from a group of electron-withdrawing substituents;
• wherein each of said imidazole units is connected to the main polymer chain through said 2 position;
• providing a polymer of the formula:
• where R1 is hydrogen or a substituted or unsubstituted alkyl having up to 10 carbon atoms, R2 is hydrogen or a substituted or unsubstituted alkyl having up to 4 carbon atoms, and R3 is hydrogen.