['CCCCNC(=O)CO', 'O=Cc1ccc2c3c(cccc13)CC2', 'CCCCN', 'O=CCOC(=O)c1ccc2c3c(cccc13)CC2', 'CCCCNC(C)=O', 'O=C(O)c1ccc2c3c(cccc13)CC2', 'CCCC', 'NC(=O)COC(=O)c1ccc2c3c(cccc13)CC2', 'CCCCNC(=O)COC=O', 'c1cc2c3c(cccc3c1)CC2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cc2c3c(cccc3c1)CC2.