COc1cc(/C=C2\SC(=S)N(CCC(=O)Nc3ccccc3O)C2=O)cc(OC)c1OC
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?