CCOC(=O)CSc1cc(C[S+]([O-])c2ccc(Cl)cc2)nc(-c2ccccc2)n1
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?