Novel method of the synthesis and hybridization properties of an oligonucleotide containing non-ionic diisopropylsilyl internucleotide linkage

Efficient synthesis of a dithymidine dinucleotide analog bearing a diisopropylsilyl linkage instead of a phosphodiester linkage is described with respect to its incorporation into oligonucleotides. The diisopropylsilyl linkage was introduced into the oligonucleotide by preparation of the phosphoramidite derivative of a dithymidine dimer unit. The diisopropylsilyl-modified oligonucleotide exhibited hybridization behavior with both single strand and duplex DNA. The thermal stability of both the duplex and triplex showed a relative instability compared to the corresponding natural phosphodiester DNA, because of the steric hindrance of the isopropyl group on the silicon atom.