COc1cc([C@H]2Oc3cc(O)c4c(=O)cc(-c5ccc(O)cc5)oc4c3O[C@@H]2CO)ccc1O
A rotatable bond is defined as any single non-ring bond, attached to a non-terminal, non-hydrogen atom. Amide C-N bonds are not counted because of their high barrier to rotation.  How many rotatable bonds does the molecule have?