CCOc1ccc(CCNC(=O)c2c3c(nc4ccccc24)C(=O)N(C2CCCCC2)C3)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?