['CC(C)C=O', 'c1cnn(CCN2CCNCC2)c1', 'CCn1cccn1', 'CC(C)C(=O)N1CCNCC1', 'c1cn[nH]c1', 'CCN1CCN(C(=O)C(C)C)CC1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cnn(CCN2CCNCC2)c1.