COc1cccc(-c2c(NC(=O)c3ccco3)n(-c3ccc(C)cc3)nc(C)c2=O)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?