['CC(C)N', 'O=CNC1CC12CCCC2', 'CC(C)NC=O', 'NC1CC12CCCC2', 'CCC', 'NC(=O)NC1CC12CCCC2', 'CC(C)NC(N)=O', 'C1CCC2(C1)CC2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C1CCC2(C1)CC2.