(15N5)-Labeled Adenine Derivatives: Synthesis and Studies of Tautomerism by 15N NMR Spectroscopy and Theoretical Calculations
摘要:
Since the nitrogens of nucleosides and nucleotides play an important role in the molecular recognition of these compounds, N-15 NMR became a method of choice in this field. Fully N-15-labeled adenine, required in the latter studies, was obtained in four synthetic steps, in a good yield. Likewise, (N-15(5))-2-hexylthioether-adenine and (N-15(5))-8-Br-adenine were obtained in five synthetic steps from the relatively inexpensive N-15 sources: N-15-NH4Cl, N-15-NH4OH, N-15-NaNO2. Full N-15 labeling of these adenine prototypes enabled to obtain high-resolution 15N NMR spectra of these bases at 60.8 MHz. Furthermore, the spectra suggested the existence of the N3-H species in the tautomeric mixtures of these compounds in solution, in addition to the well-reported N9-H (major) and N7-H (minor) tautomers. These observations were also supported by quantum mechanical calculations of the tautomeric equilibria in the gas phase and in solution of the above-mentioned adenine compounds. The gas-phase tautomeric equilibria were estimated using density functional theory and second-order perturbation theory methods. Solvent effects were included by means of both continuum and discrete solvation models. The observation of the existence of the N3-H tautomer has a clear impact on the possible H-bonding patterns of these adenine prototypes and on their molecular recognition by various biological macromolecules. The above(15)N-labeled analogues are expected to find use as N-15 NMR probes for numerous biochemical studies.
(15N5)-Labeled Adenine Derivatives: Synthesis and Studies of Tautomerism by 15N NMR Spectroscopy and Theoretical Calculations
摘要:
Since the nitrogens of nucleosides and nucleotides play an important role in the molecular recognition of these compounds, N-15 NMR became a method of choice in this field. Fully N-15-labeled adenine, required in the latter studies, was obtained in four synthetic steps, in a good yield. Likewise, (N-15(5))-2-hexylthioether-adenine and (N-15(5))-8-Br-adenine were obtained in five synthetic steps from the relatively inexpensive N-15 sources: N-15-NH4Cl, N-15-NH4OH, N-15-NaNO2. Full N-15 labeling of these adenine prototypes enabled to obtain high-resolution 15N NMR spectra of these bases at 60.8 MHz. Furthermore, the spectra suggested the existence of the N3-H species in the tautomeric mixtures of these compounds in solution, in addition to the well-reported N9-H (major) and N7-H (minor) tautomers. These observations were also supported by quantum mechanical calculations of the tautomeric equilibria in the gas phase and in solution of the above-mentioned adenine compounds. The gas-phase tautomeric equilibria were estimated using density functional theory and second-order perturbation theory methods. Solvent effects were included by means of both continuum and discrete solvation models. The observation of the existence of the N3-H tautomer has a clear impact on the possible H-bonding patterns of these adenine prototypes and on their molecular recognition by various biological macromolecules. The above(15)N-labeled analogues are expected to find use as N-15 NMR probes for numerous biochemical studies.
(<sup>15</sup>N<sub>5</sub>)-Labeled Adenine Derivatives: Synthesis and Studies of Tautomerism by <sup>15</sup>N NMR Spectroscopy and Theoretical Calculations
作者:Avital Laxer、Dan T. Major、Hugo E. Gottlieb、Bilha Fischer
DOI:10.1021/jo010344n
日期:2001.8.1
Since the nitrogens of nucleosides and nucleotides play an important role in the molecular recognition of these compounds, N-15 NMR became a method of choice in this field. Fully N-15-labeled adenine, required in the latter studies, was obtained in four synthetic steps, in a good yield. Likewise, (N-15(5))-2-hexylthioether-adenine and (N-15(5))-8-Br-adenine were obtained in five synthetic steps from the relatively inexpensive N-15 sources: N-15-NH4Cl, N-15-NH4OH, N-15-NaNO2. Full N-15 labeling of these adenine prototypes enabled to obtain high-resolution 15N NMR spectra of these bases at 60.8 MHz. Furthermore, the spectra suggested the existence of the N3-H species in the tautomeric mixtures of these compounds in solution, in addition to the well-reported N9-H (major) and N7-H (minor) tautomers. These observations were also supported by quantum mechanical calculations of the tautomeric equilibria in the gas phase and in solution of the above-mentioned adenine compounds. The gas-phase tautomeric equilibria were estimated using density functional theory and second-order perturbation theory methods. Solvent effects were included by means of both continuum and discrete solvation models. The observation of the existence of the N3-H tautomer has a clear impact on the possible H-bonding patterns of these adenine prototypes and on their molecular recognition by various biological macromolecules. The above(15)N-labeled analogues are expected to find use as N-15 NMR probes for numerous biochemical studies.