COc1ccc(C2C3=C(O)CC(c4ccco4)CC3=NC(C)=C2C(=O)OCC2CCCO2)cc1O
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?