COC(=O)c1ccc(C2c3c(oc4cc(C)c(C)cc4c3=O)C(=O)N2CCCN(C)C)cc1
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?