COC(=O)C1=C(OC)C(=P2(c3ccccc3)CC(c3ccccc3)=C2c2ccccc2)C(C(=O)OC)=C1C(=O)OC
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?