COc1cc(OC)c(NC(=O)C(C)n2c(=O)cc(-c3ccccc3)c3c(C)nn(C)c32)cc1Cl
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?