['CCC(C)N', 'O=CCNC(=O)Cn1cncn1', 'O=CCn1cncn1', 'CCC(C)NC(=O)CN', 'CCCC', 'NC(=O)CNC(=O)Cn1cncn1', 'CCC(C)NC(C)=O', 'NC(=O)Cn1cncn1', 'c1nc[nH]n1', 'CCC(C)NC(=O)CNC(C)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nc[nH]n1.