['CC(C)(C)NCC=O', 'Cn1ncc2c1CCCC2N', 'CC(C)(C)N', 'CC(=O)NC1CCCc2c1cnn2C', 'CC(C)C', 'Cn1ncc2c1CCCC2NC(=O)CN']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1n[nH]c2c1CCCC2.