NMR and UV Study of 1,1′-(α,ω-Alkanediyl)bis[thymine] and 1,1′-(α,ω-Alkanediyl)bis[uracil]

Treatment of thymine or uracil with Br(CH2)nBr (n = 3—10) in the presence of t-BuOK gave 1,1′-(α,ω-alkanediyl)bis[thymine] or 1,1′-(α,ω-alkanediyl)bis[uracil] together with 1-(ω-bromoalkyl)thymine or 1-(ω-bromoalkyl)uracil. The structures of these products were determined on the basis of the coupling constants between 5- and 3-positions of uracil ring on the 1H NMR spectra. Molecular aggregation of the thymine and uracil rings of these compounds in aqueous solution was studied on the basis of their 1H NMR and UV spectra. A stacking interaction of the two thymine rings linked by shorter polymethylene chains such as trimethylene and tetramenthylene groups was observed.