['CNC', 'C/C(=N\\NC(=O)c1ncnc(N(C)C)n1)c1ccc(N)cc1', 'CN(C)c1ncnc(N(C)C)n1', 'C/C(=N\\NC=O)c1ccc(N)cc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=C(NN=Cc1ccccc1)c1ncncn1.