COc1ccc(OC)c(NC(=O)CCC/C(CC(=O)c2ccc(O)c(OC)c2)=N\NC(=O)C[N+](C)(C)C)c1.[Cl-]
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?