Synthesis, biochemical and biological studies on oligonucleotides bearing a lipophilic dimethoxytrityl group.

Dimethoxytritylphosphono-oligonucleotide conjugates have been prepared. They are totally resistant to nucleases present in human serum and do not affect cleavage of a complementary oligoribonucleotide by RNase H. Conjugates possessing a phosphate backbone gave better antisense inhibition of expression of plasminogen activator inhibitor type-1 within endothelial cells as compared with unconjugated oligonucleotides.