CCOc1cc(C2C3=C(O)CCCC3=NC(C)=C2C(=O)OC(C)C)cc([N+](=O)[O-])c1O
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?