['NC=O', 'NC(=O)CSc1nccc(C(F)(F)F)n1', 'NC(N)=O', 'O=CCSc1nccc(C(F)(F)F)n1', 'CC(=O)NC(N)=O', 'FC(F)(F)c1ccnc(S)n1', 'FC(F)F', 'NC(=O)NC(=O)CSc1ncccn1', 'NC(=O)NC(=O)CS', 'FC(F)(F)c1ccncn1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cncnc1.