COc1cccc2cc(C(=O)C3=C(O)C(=O)N(c4cc(C)on4)C3c3cccs3)oc12
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?