['CNC', 'CN(C)C(=O)N1CCN(CC=O)CC1', 'CN(C)C=O', 'CN(C)C(=O)CN1CCNCC1', 'CN(C)C(=O)CN1CCN(C=O)CC1', 'CC(=O)N(C)C', 'CN(C)C(=O)N1CCNCC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CNCCN1.