COc1cccc(Nc2sc(C(=O)c3ccc(Cl)cc3)c(N)c2C(=O)NCCc2ccc(OC)c(OC)c2)c1
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?