O=C1/C(=C/c2ccc3c(c2)OCO3)Oc2cc(OCC(=O)N3CC(O)C[C@H]3C(=O)O)ccc21
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?