Cc1cc(C)c2nc3c(c(C(O)C4CCCCN4)c2c1)CC/C3=C\c1ccc(Cl)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?