COc1cccc(CNC(=O)C(C)n2ccc3cc(S(=O)(=O)N4CCCC4)ccc32)c1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?