TY - JOUR
T1 - New Observations on Tautomerism and Ionization Processes in Hypoxanthines and 6‐Thiopurines
AU - Lichtenberg, D.
AU - Bergmann, F.
AU - Neiman, Z.
PY - 1972
Y1 - 1972
N2 - Ultraviolet spectra show that hypoxanthine and 6‐thiopurine are present in aqueous solution predominantly as 1H, 9H‐tautomers. However, a 3‐methyl group causes the imidazole ring to assume the 7‐NH form. The sequence of anion formation in hypoxanthine is 9(7) → 1 and in 6‐thiopurine 1 → 9(7). The NMR spectra suggest that the mono‐anion of hypoxanthine is a mixture of tautomers. Protonation always takes place in the imidazole ring, with the exception of 3‐methyl derivatives. In the latter, formation of mono‐cations involves the pyrimidine moiety.
AB - Ultraviolet spectra show that hypoxanthine and 6‐thiopurine are present in aqueous solution predominantly as 1H, 9H‐tautomers. However, a 3‐methyl group causes the imidazole ring to assume the 7‐NH form. The sequence of anion formation in hypoxanthine is 9(7) → 1 and in 6‐thiopurine 1 → 9(7). The NMR spectra suggest that the mono‐anion of hypoxanthine is a mixture of tautomers. Protonation always takes place in the imidazole ring, with the exception of 3‐methyl derivatives. In the latter, formation of mono‐cations involves the pyrimidine moiety.
UR - http://www.scopus.com/inward/record.url?scp=84987339816&partnerID=8YFLogxK
U2 - 10.1002/ijch.197200081
DO - 10.1002/ijch.197200081
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AN - SCOPUS:84987339816
SN - 0021-2148
VL - 10
SP - 805
EP - 817
JO - Israel Journal of Chemistry
JF - Israel Journal of Chemistry
IS - 4
ER -