COC(=O)C1(C(=O)OC)CC(=O)c2cc3c(cc2-c2c(cc(OC)c(OC)c2OC)C1)OCO3
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?