['C#CCN', 'O=CCCc1nc2ccccc2[nH]1', 'C#CC', 'NC(=O)CCc1nc2ccccc2[nH]1', 'C#CCNC(=O)CC', 'c1ccc2[nH]cnc2c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2[nH]cnc2c1.