COc1cccc(CNS(=O)(=O)c2cc(Br)cc3c2N(C(C)=O)C(C)C3)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?