['CO', 'CNc1nnc(S[C@H](C)C=O)s1', 'CCC(=O)OC', 'CNc1nnc(S)s1', 'CN', 'COC(=O)[C@@H](C)Sc1nncs1', 'COC(=O)[C@@H](C)S', 'CNc1nncs1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nncs1.