['CC(C)C=O', 'NCCNC(=O)N1CCc2sccc2C1', 'CC(C)C(=O)NCCN', 'O=CN1CCc2sccc2C1', 'c1cc2c(s1)CCNC2', 'CC(C)C(=O)NCCNC=O', 'CC(C)C(N)=O', 'CCNC(=O)N1CCc2sccc2C1', 'CCNC(=O)C(C)C', 'NC(=O)N1CCc2sccc2C1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cc2c(s1)CCNC2.