['NC(N)=O', 'COc1cccc2c1N(CC=O)CCC2', 'NC=O', 'COc1cccc2c1N(CC(N)=O)CCC2', 'CO', 'NC(=O)NC(=O)CN1CCCc2ccccc21', 'CC(=O)NC(N)=O', 'COc1cccc2c1NCCC2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2c(c1)CCCN2.