COc1ccc(/N=C2\S/C(=C\c3ccc(OC(C)C(=O)O)c(OC)c3)C(=O)N2CCc2c[nH]c3ccccc23)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?