TY - JOUR
T1 - Nuclear magnetic resonance spectra of xanthines and thioxanthines
AU - Lichtenberg, D.
AU - Bergmann, F.
AU - Neiman, Z.
PY - 1971
Y1 - 1971
N2 - The n.m.r. signal of the 8-proton in xanthines is shifted downfield more strongly by introduction of a 2 -than of a 6-thioxo-group. The signals of N-methyl groups are also shifted to lower field, but the effect depends strictly on the distance between the methyl and the thioxo-group. Thus in 2-thioxanthines, the displacement decreases in the following order: 1-methyl = 3-methyl > 7-methyl, and in 6-thioxanthines the sequence is 1-methyl > 7-methyl > 3-methyl > 9-methyl.
AB - The n.m.r. signal of the 8-proton in xanthines is shifted downfield more strongly by introduction of a 2 -than of a 6-thioxo-group. The signals of N-methyl groups are also shifted to lower field, but the effect depends strictly on the distance between the methyl and the thioxo-group. Thus in 2-thioxanthines, the displacement decreases in the following order: 1-methyl = 3-methyl > 7-methyl, and in 6-thioxanthines the sequence is 1-methyl > 7-methyl > 3-methyl > 9-methyl.
UR - https://www.scopus.com/pages/publications/37049124326
U2 - 10.1039/J39710001939
DO - 10.1039/J39710001939
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AN - SCOPUS:37049124326
SN - 0022-4952
SP - 1939
EP - 1941
JO - Journal of the Chemical Society C: Organic Chemistry
JF - Journal of the Chemical Society C: Organic Chemistry
ER -