CCn1c(SC)nc(=O)c(C(c2ccc(OC)c(O)c2)c2c(O)n(CC)c(SC)nc2=O)c1O
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?