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Isotope Effects on the Lipophilicity of Deuterated Caffeines
Author(s) -
Bechalany Antoine,
El Tayar Nabil,
Carrupt PierreAlain,
Testa Bernard,
Falconnet JeanBernard,
Cherrah Yahia,
Benchekroun Youssef,
Brazier JeanLouis
Publication year - 1989
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19890720308
Subject(s) - lipophilicity , chemistry , isotopomers , caffeine , kinetic isotope effect , deuterium , intramolecular force , isotope , stereochemistry , medicinal chemistry , computational chemistry , organic chemistry , molecule , psychology , physics , quantum mechanics , psychiatry
In the present study, it is confirmed that the deuteration of CH groups is accompanied by a small but genuine decrease in lipophilicity. The lipophilicity of deuterated isotopomers of caffeine was measured by reversed‐phase HPLC. Overall, lipophilicity was shown to decrease when going from unlabelled caffeine to the three isomeric trideuterated caffeines, then to the three isomeric hexadeuterated caffeines, and finally to nonadeuterated caffeine. In addition, position‐specific effects were also proven. E.g. (7‐ methyl ‐ 2 H 3 )caffeine experienced a smaller isotope effect than its two positional isomers. Both a cavity factor (decreased volume of deuterated isotopomers) and intramolecular electronic effects are postulated to operate.