Oligonucleotides containing 2′-O-modified purines

A compound having the structure:

• wherein
• X is R1—(R2)n;
• R1 is C1-C20 alkyl, C4-C20 alkenyl, or C2-C20 alkynyl;
• R2 is halogen, nitro, nitroso, nitrile, trifluoromethyl, trifluoromethoxy, O-alkyl, S-alkyl, NH-alkyl, N-dialkyl, O-aryl, S-aryl, NH-aryl, O-aralkyl, S-aralkyl, NH-aralkyl, imidazole, N-phthalimido, azido, hydrazino, hydroxylamino, isocyanato, sulfoxide, sulfone, sulfide, disulfide, silyl, aryl, heterocycle, carbocycle, intercalator, reporter molecule, conjugate, polyamine, polyamide, polyalkylene glycol, or polyether;
• either one of T3 and T5 is OH, a hydroxyl blocking group, phosphate or an activated phosphate group and the other of T3 and T5 is a nucleotide, or both T3 and T5 are nucleotides;
• and
• n is an integer from 1 to 6.

A compound having the structure:

• wherein
• X is R1—(R2)n;
• R1 is C4-C20 alkyl, C4-C20 alkenyl, or C2-C20 alkynyl and n is 0;
• or R1 is C1-C20 alkyl, C2-C20 alkenyl, or C2-C20 alkynyl and n is 1 to 6;
• R2 is hydroxyl, thiol, keto, carboxyl, or amino;
• and
• either one of T3 and T5 is OH, a hydroxyl blocking group, phosphate or an activated phosphate group and the other of T3 and T5 is a nucleotide or both T3 and T5 are nucleotides.

A compound having the structure:

• wherein
• X is R1—(R2)n;
• R1 is C1-C20 alkyl, C4-C20 alkenyl, or C2-C20 alkynyl;
• R2 is hydroxyl, thiol, keto, carboxyl, or amino;
• either one of T3 and T5 is OH, a hydroxyl blocking group, phosphate or an activated phosphate group and the other of T3 and T5 is a nucleotide, or both T3 and T5 are nucleotides;
• and
• n is an integer from 0 to 6.