['C#CCN', 'O=Cc1ccc(-n2cnnn2)cc1', 'C#CC', 'NC(=O)c1ccc(-n2cnnn2)cc1', 'C#CCNC=O', 'c1ccc(-n2cnnn2)cc1', 'c1nnn[nH]1', 'C#CCNC(=O)c1ccccc1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc(-n2cnnn2)cc1.