Synthesis of sulfide-linked di-or oligonucleotide analogs and incorporation into antisense dna or rna

Abstract From the Canadian patent

An oligonucleotide analog of formula I in which one or more of the internucleoside phosphodiester groups are replaced by nonhydrolysable dialkyl sulfide, sulfoxide or sulfone linkages such, as in:, in which R and R' are independently selected from H DNA, RNA, unsubstituted or substituted by I nucleoside, nucleotides and, analogs thereof; B is a base having a heterocyclic ring X is, independently O, CH2 or S; Y is independently H OH or O-alkyl; Y', is H or O-alkyl; n is 0 1 or 2; and m is 0 or an integer. These compounds are useful for binding selectively to complementary DNA or RNA strands (particularly mRNA strands) for use in regulating gene expression and as biological probes.