[Chimera-users] Tautomer Prediction

[Nancy]

Hi All,

Using MarvinSketch v5.3.3 (ChemAxon software), the predicted pKa value of
the acidic hydrogen on the thiazolidinedione ring of pioglitazone is 4.57
(see attached "Figure_1.gif").  Therefore, the predominant species at pH 7.0
predicted by MarvinSketch is the one depicted in "Figure_2.gif".  The
different tautomeric forms predicted by MarvinSketch are shown in
"Figure_3.gif".

Can anyone explain where these predictions come from, and if they are
correct?  Also, are there other programs that can accurately predict
tautomeric forms?

Thanks,
Nancy
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