CCOC(=O)C1=C(Nc2ccc(OC)cc2)S/C(=C\c2ccc(-c3ccccc3C(=O)O)o2)C1=O
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?