['CO', 'O=CCCCCCNC(=O)Cn1c2ccccc2c(=O)c2ccccc21', 'COC(=O)CCCCCN', 'O=CCn1c2ccccc2c(=O)c2ccccc21', 'CCCCCC(=O)OC', 'NC(=O)Cn1c2ccccc2c(=O)c2ccccc21', 'COC(=O)CCCCCNC(C)=O', 'O=c1c2ccccc2[nH]c2ccccc12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1c2ccccc2[nH]c2ccccc12.