Oligonucleotide Analogues with Integrated Bases and Backbones Part 19 Gelation of Organic Solvents by Self-Complementary A*[s]U-(*) Dinucleosides

The A*[s]U-(*) dinucleosides 1 and 2 form thermoreversible gels in organic solvents. The basis of the gelation is the formation of linear aggregates by base pairing following desolvation of the nucleobases. This is evidenced by the absence of gel formation by the C(6)-deaminated analogue 3 of 1, the correlation of gelation with the anti-conformation, as preferred for 1, and the temperature-, concentration-, and time-dependent CD spectra. The gels were also characterized by the minimum gelation concentration, the gel-sol transition (melting) temperature and rheological properties.