['CO', 'CN(C)c1ncc(C=O)c(CCl)n1', 'CNC', 'COC(=O)c1cncnc1CCl', 'COC=O', 'CN(C)c1nccc(CCl)n1', 'CCl', 'COC(=O)c1cnc(N(C)C)nc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cncnc1.