CC1=CC2OC3CC(OC(=O)/C=C/C=C/C(OCCC4=CC(=O)OC4)C(C)O)C(C)(C2(CO)CC1)C31CO1
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?