['O=C[C@H]1CCCC(=O)N1', 'NC1CCCCNC1=O', 'O=C1CCCCCN1', 'NC(=O)[C@H]1CCCC(=O)N1', 'O=C1CCCCN1', 'O=CNC1CCCCNC1=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C1CCC[C@H](C(=O)NC2CCCCNC2=O)N1.