The use of 15N-NMR spectroscopy for assigning the structures of isomeric N7- and N9-substituted purines

N7‐ and N9‐substituted purine derivatives: a 15N NMR study

“…16,17 In addition to standard 1 H and 13 C NMR techniques, 1 H- 15 N NMR experiments proved to be very useful in determining the position of the alkylation in these nitrogen-rich compounds. 15,18 In comparison with adenine, guanine displays a strikingly different behavior in glycosylation and alkylation reactions. Under the usual conditions, the N 9 -and N 7 -regioisomers form in a 1 : 1 ratio.…”

“…An extensive 15 N NMR study of selected N 7 /N 9 -substituted purine analogs by Remaud et al 18 indicated considerable differences in the electronic structures between the pairs of N 7 /N 9 isomers. 15 N cross-polarization magic angle spinning (CP/MAS) spectra of adenine and guanine, including the determination of the principal components of the shift tensors, have been reported.…”

Synthesis and 15N NMR characterization of 4‐vinylbenzyl substituted bases of nucleic acids

“…The study of protons and carbon atoms provides an only indirect piece of information about the nitrogen skeleton, which is most sensitive to the substitution type. Therefore, very useful for this purpose appeared to be the techniques based on 1 5 N NMR spectroscopy [10][11][12]. Thorough 1 5 N NMR studies of selected N 7 / N 9 -substituted purine analogues carried out by Remaud et al [ 11] showed substantial differences in electron structures of the N 7 / N 9 isomers.…”

“…Therefore, very useful for this purpose appeared to be the techniques based on 1 5 N NMR spectroscopy [10][11][12]. Thorough 1 5 N NMR studies of selected N 7 / N 9 -substituted purine analogues carried out by Remaud et al [ 11] showed substantial differences in electron structures of the N 7 / N 9 isomers. This paper [11] and the results published by Marek et al [12] resulted in certain conclusions that are useful in diagnosis of substitution type in purine derivatives.…”

“…Thorough 1 5 N NMR studies of selected N 7 / N 9 -substituted purine analogues carried out by Remaud et al [ 11] showed substantial differences in electron structures of the N 7 / N 9 isomers. This paper [11] and the results published by Marek et al [12] resulted in certain conclusions that are useful in diagnosis of substitution type in purine derivatives. Perhaps the most useful is the chemical shift of N-3 nitrogen.…”