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

Abstract

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.

Cross-linked and functionalized ‘universal polymer backbones’ via simple, rapid, and orthogonal multi-site self-assembly

“…10 6 M 21 ). 28,29,33 Non-covalent cross-linkers are made from alkyl chains containing pyridine, uracil derivatives, 4,34 or isopthalamide derivatives at each terminus. These recognition units bind palladated pincer complexes, 17,19,25,31 diaminopyridine moieties, 26,27 or cyanuric wedges, respectively.…”

NMR Study of Stacking Interactions between Thymine and 1,3-Dimethylxanthine Rings

“…The preparation of 1 was performed by the treatment of theophylline (1,3-dimethylxanthine) and 1 -(w-bromoalky1)thymine (2) [9] in the presence of tert-BuOK in N,N-dimethylformamide (DMF). The results are shown in Table I.…”

“…The 'H NMR spectra of 1 in D20 at 27°C were measured at least twice and the chemical shifts were reproduced within f 0.002ppm. Since we previously investigated the NMR spectroscopy of l,l1-(a,w-alkanediyl)-bidthymine] (3) [9] in D20, the chemical shifts of H-6 and Me-5 of thymine ring of 1 were compared with those of 3 in D20 at 27°C. Figures 2 and 3 show the relationships of the chemical shifts of H-6 and Me-5 of thymine ring of 1, respectively, in D20 at 27°C.…”

“…The elemental analyses were performed by the Analytical Center of Kyoto University. The preparation of I-(w-bromoalkyl) thymine (2) was previously reported [9].…”

“…Into a solution of theophylline (1,3-dimethylxanthine) (I mmol) and tert-BuOK (I mmol) in DMF (50ml), 1-(w-bromoalky1)thymine (2) [9] (I mmol) was added. The mixture was stirred at room temperature for 24h.…”