['C#CCN', 'COc1ccc2nc(C)c(C=O)cc2c1', 'CO', 'C#CCNC(=O)c1cc2ccccc2nc1C', 'C#CC', 'COc1ccc2nc(C)c(C(N)=O)cc2c1', 'C#CCNC=O', 'COc1ccc2nc(C)ccc2c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2ncccc2c1.