COc1cc([C@@H]2c3cc4c(cc3[C@H](OC3OC5COC(C(C)C)OC5C(O)C3O)C3COC(=O)[C@@H]32)OCO4)cc(OC)c1O
A lower number of negative pKa indicates that the acid dissociates more entirely in water. What is the negative pKa of this molecule?