COc1ccc2c3c([nH]c2c1)C1CC2C(CC(O)C(OC)C2C(=O)O)CN1CC3
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?