Oligonucleotides with (N-thymin-1-ylacetyl) 1-phenylserinol in backbone: Chiral acyclic analogues that form dna triplexes

The synthesis of oligonucleotides containing chiral acyclic 2(R/S)-(N-thymin-1-ylacetyl)-amino-1(R/S)-phenyl-1,3-propanediol unit in the backbone (l, R=Ar) is described. When used as third strand of a triplex with complementary natural duplex, the modified oligonucleotides form stable triplexes with triplex ↔ duplex transition Tm dependent on the number, position and stereochemistry of modification.