['Nc1ccc(Cl)cc1', 'CC(C)OP(=O)(CC=O)OC(C)C', 'CCC', 'CC(C)OP(=O)(O)CC(=O)Nc1ccc(Cl)cc1', 'Clc1ccccc1', 'CC(C)OP(=O)(CC(N)=O)OC(C)C']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccccc1.