['CC(C)(C)C=O', 'NCC(=O)Nc1ncn[nH]1', 'Nc1ncn[nH]1', 'CC(C)(C)C(=O)NCC=O', 'CC(C)(C)C(N)=O', 'CC(=O)Nc1ncn[nH]1', 'c1nc[nH]n1', 'CC(C)(C)C(=O)NCC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nc[nH]n1.