COc1ccc(-c2nc(SCC(=O)N/N=C/c3ccc(O)c(OC)c3)[nH]c2-c2ccc(OC)cc2)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?