['C#CCN', 'O=CCN1CCCc2cc(F)ccc21', 'C#CC', 'NC(=O)CN1CCCc2cc(F)ccc21', 'C#CCNC(C)=O', 'Fc1ccc2c(c1)CCCN2']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2c(c1)CCCN2.