Взаємодія з карбоксилат-іоном у безводному ДМСО зсуває прототропну кето-енольну рівновагу в нуклеозидах урацилу і тиміну в бік енольної таутомерної форми: дані спектроскопії 1Н ЯМР

S A Samijlenko,I V Kondratyuk,D M Hovorun

doi:10.7124/bc.000656

Abstract

Взаємодія з карбоксилат-іоном у безводному ДМСО зсуває прототропну кето-енольну рівновагу в нуклеозидах урацилу і тиміну в бік енольної таутомерної форми: дані спектроскопії 1Н ЯМР

Highlights

The disappearance of signals of N3H aglycon protons^ and all hydroxy I protons of gly cosy lie fragment was observed in II NMR spectra of four nucleosides of uracil and thymine — U, dU, T and rT — in anhydrous DMSO in the presence of carboxylate ion
These changes were interpreted as a result of the N3H -> 02H diketo-ketoenolic transition in the base residues under the formation of complex between nucleosides and ligand molecules: one carboxylate ion forms two H-bonds with groups 02H and 05'H, the other — two H-bonds with hydroxy I groups 02'H and ОЗ'Н in the case of a riboside or one H-bond with group 03'H of a deoxyriboside
D. Nitrogen-15 nucleic magnetic resonance spectroscopy of some nucleosides and nucleotides / / J

Summary

Introduction

The disappearance of signals of N3H aglycon protons^ and all hydroxy I protons of gly cosy lie fragment was observed in II NMR spectra of four nucleosides of uracil and thymine — U, dU, T and rT — in anhydrous DMSO in the presence of carboxylate ion. These changes were interpreted as a result of the N3H -> 02H diketo-ketoenolic transition in the base residues under the formation of complex between nucleosides and ligand molecules: one carboxylate ion forms two H-bonds with groups 02H and 05'H, the other — two H-bonds with hydroxy I groups 02'H and ОЗ'Н in the case of a riboside or one H-bond with group 03'H of a deoxyriboside. Orders of the complexes' stability were established according to which the canonical nucleosides U and T form more stable complexes with carboxylate ion, than metabolites dU and rT.

Results

Conclusion