CC(=O)O[C@]1(C)C(=O)OC/C2=C/CN(C)CCC(OC(=O)[C@@](O)(C(C)O)C[C@H]1C)C2=O
Hydrogen bond acceptor: The atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom. How many hydrogen bond acceptors does the molecule have?