Nucleic acid components and their analogues. XXVI. Ultraviolet and infrared spectra of 5-azauracil and related compounds

Abstract

The ultraviolet and infrared spectra of 5-azauracil and some of its derivatives have been measured. On the basis of the infrared spectra it has unambiguously been proved that 5-azauracil and its derivatives exist in the dilactam form in solutions of dioxane and ethanol. The results of the measurements of the ultraviolet spectra enable us to assume the existence of the dilactam structure of 5-azauracil in neutral aqueous solutions. Using the dependence of the ultraviolet spectra on the pH value of aqueous solutions the order of dissociation for 5-azauracil has been determined and the second dissociation constant of this compound measured.

Mapping the Landscape of Potentially Primordial Informational Oligomers: Oligodipeptides and Oligodipeptoids Tagged with Triazines as Recognition Elements

“…In a careful spectroscopic study of the 5‐aza analogue of uracil, Jonas et al 35. could not find any evidence for this compound to exist in aqueous solution in a tautomeric form other than the dilactam form, and for the solid state of another 2,4‐dioxo triazine derivative, the lactam form is confirmed by an X‐ray study 36.…”

A Hybrid statistical mechanics—quantum chemical model for proton transfer in 5‐azauracil and 6‐azauracil in water solution

“…5‐azauracil (1,3,5‐triazine‐2,4(1H,3H)‐dione, 5‐AU) is considered to be a potential anticancer agent. Experimental investigations performed in gas phase, solid state, or in solution indicate that the amino‐oxo tautomer of 5‐azauracil is the most stable one. Infrared spectra of 5‐azauracil in dioxan and ethanol solutions indicate the presence of the dioxo tautomeric form .…”

“…Experimental investigations performed in gas phase, solid state, or in solution indicate that the amino‐oxo tautomer of 5‐azauracil is the most stable one. Infrared spectra of 5‐azauracil in dioxan and ethanol solutions indicate the presence of the dioxo tautomeric form . Interpretation of the UV spectra of 5‐azauracil in water is ambiguous .…”

“…[25] Interpretation of the UV spectra of 5-azauracil in water is ambiguous. [25] The tautomerism of 5-azaurcil in deuterated dimethyl sulfoxide (DMSO) was investigated by Pike [26] by means of Nuclear Magnetic Resonance (NMR) spectroscopy, but his results were not conclusive. 6-azauracil (1,2,4-triazine-3,5(2H,4H)-dione, 6-AU) was formerly used as an antitumor drug and has been studied extensively.…”

“…Infrared spectra of 5‐azauracil in dioxan and ethanol solutions indicate the presence of the dioxo tautomeric form . Interpretation of the UV spectra of 5‐azauracil in water is ambiguous . The tautomerism of 5‐azaurcil in deuterated dimethyl sulfoxide (DMSO) was investigated by Pike by means of Nuclear Magnetic Resonance (NMR) spectroscopy, but his results were not conclusive.…”