Oligonucleotide Analogues with a ‘Nucleobase‐Including Backbone’. Part 10

Abstract

AbstractThe dinucleoside analogues 24, 25, 28–30, and 33 associate in CDCl3 solution. Association constants, as determined from the concentration‐dependent chemical shift for HN(3) of the uridine moiety and from thermodynamic parameters, range from 265 M−1 (33) to 3220 M−1 (30). The association of 31 in CDCl3 is too strong to be determined (concentration independent δ(HN(3)) of ca. 12.8 ppm) and the fully deprotected dimer 32 proved insufficiently soluble in CDCl3. This observation strongly evidences that structural differentiation of oligonucleotides and their analogues into backbone and nucleobases is not required for pairing. The dinucleotide analogues were prepared by O‐alkylation of C(8)‐unsubstituted or of C(8)‐oxymethylated, partially protected adenosines by the C(6)‐mesyloxy‐ or C(6)‐halomethylated uridines 20–22, followed by partial or total deprotection.