COc1ccccc1/C=C/c1nc(S(=O)(=O)c2ccccc2)c(NCCN(C)C)o1
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?