['NC(N)=O', 'CN(CC=O)Cc1cnn(C)c1', 'NC=O', 'CN(CC(N)=O)Cc1cnn(C)c1', 'CC(=O)NC(N)=O', 'CNCc1cnn(C)c1', 'Cc1cnn(C)c1', 'CNCC(=O)NC(N)=O', 'Cn1cccn1', 'CN(C)CC(=O)NC(N)=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cn[nH]c1.