['C#CCN', 'Cc1cc(C)c2cc(C=O)[nH]c2c1', 'C#CC', 'Cc1cc(C)c2cc(C(N)=O)[nH]c2c1', 'C#CCNC=O', 'Cc1cc(C)c2cc[nH]c2c1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ccc2[nH]ccc2c1.