CC(=O)C1C(=O)CC(C)(C)CC1=O    mol2736    0_1
CC(=O)C1C(=O)[CH-]C(C)(C)CC1=O    mol2736    -1_1
CC(=O)[C-]1C(=O)CC(C)(C)CC1=O    mol2736    -1_2
[CH2-]C(=O)C1C(=O)CC(C)(C)CC1=O    mol2736    -1_3