COc1cccc(/C=C/C(=O)OCC(=O)N(C)CC(=O)Nc2ccccc2Cl)c1OC
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?