['CN', 'Cc1ncc(C)c(CN(C)C)n1', 'CNC', 'CNCc1cnc(C)nc1C', 'CN(C)C', 'CNCc1cnc(C)nc1', 'CNC', 'Cc1nccc(CN(C)C)n1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cncnc1.