['N[C@@H]1C[C@H]1C1CC1', 'O=CN1CCOC2(CCC2)C1', 'O=CN[C@@H]1C[C@H]1C1CC1', 'C1CC2(C1)CNCCO2', 'C1CC1C1CC1', 'NC(=O)N1CCOC2(CCC2)C1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(N[C@@H]1C[C@H]1C1CC1)N1CCOC2(CCC2)C1.