['CCO', 'CCOC(=O)C(C=O)c1ccc2c(Br)ccc(O)c2n1', 'CC', 'CCOC(=O)C(C(=O)O)c1ccc2c(Br)ccc(O)c2n1', 'CCOC(=O)CC(=O)OCC', 'Oc1ccc(Br)c2cccnc12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2ncccc2c1.