['C#CCN', 'O=CCCCNC(=O)c1ccco1', 'O=Cc1ccco1', 'C#CCNC(=O)CCCN', 'C#CC', 'NC(=O)CCCNC(=O)c1ccco1', 'NC(=O)c1ccco1', 'C#CCNC(=O)CCC', 'c1ccoc1', 'C#CCNC(=O)CCCNC=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccoc1.