COC1=CC(=O)C2=C(OC(C)=O)C3=C(CC(C)OC3=O)C3=C2C1=C1C(O3)=C(OC(C)=O)C(=O)C2=C(OC(C)=O)C3=C(CC(C)OC3=O)C=C12