CC1(C)C(=O)C(C(=O)C2CC2)C(=O)C(C)(C)C1=O    mol2702    0_1
CC1(C)C(=O)C(C(=O)[C-]2CC2)C(=O)C(C)(C)C1=O    mol2702    -1_1
CC1(C)C(=O)[C-](C(=O)C2CC2)C(=O)C(C)(C)C1=O    mol2702    -1_2