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

Abstract

Abstract The dinucleoside analogues 24, 25, 28 – 30 , and 33 associate in CDCl 3 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 CDCl 3 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 CDCl 3 . 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.