Detection of potential TNA and RNA nucleoside precursors in a prebiotic mixture by pure shift diffusion-ordered NMR spectroscopy.
Bottom Line: One potential avenue is the combination of pure shift methodology, in which NMR spectra are measured with greatly improved resolution by suppressing multiplet structure, with diffusion-ordered spectroscopy, in which NMR signals from different species are distinguished through their different rates of diffusion.Such a combination has the added advantage of working with intact mixtures, allowing analyses to be carried out without perturbing mixtures in which chemical entities are part of a network of reactions in equilibrium.The direct formation of potential RNA and TNA nucleoside precursors, amongst other adducts, was observed.
Affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK. email@example.comShow MeSH
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Mentions: When the reaction was carried out in the absence of inorganic phosphate and incubated at an initial pD of 7 at 40 °C, a complex product distribution was observed by 1H NMR spectroscopy (Figure 2 a). To obtain a more complete picture of the chemistry taking place in this mixed oxygenous/nitrogenous system, we attempted to characterise this complex mixture. Because of the outwardly complex nature of the composition, we also considered this mixture to be an ideal candidate for analysis by new pure shift NMR methods,[31–33] alongside an array of standard NMR techniques (1H-1H COSY, 1H-13C HSQC, 1H-13C HMBC and 1H DOSY).[34a–f] This is the first time that pure shift diffusion-ordered spectroscopy (DOSY) NMR methodology has been applied to a complex reaction system of partially unknown composition. By using these techniques, we confirmed the direct formation of both TNA nucleoside precursors rac-15 and rac-16 (Scheme 2 b) amongst the products from the reaction of 6 and 7. We believe these preliminary results may have direct implications for the potentially prebiotic assembly chemistry of pyrimidine threonucleotides and TNA.
Affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK. firstname.lastname@example.org