COCc1n[nH]c2c1C(c1cc(OC)c(O)c(OC)c1)C(C#N)=C(N)O2
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?