['CCCC', 'CCCCNCc1nnc(C2CC2)o1', 'Cc1nnc(C2CC2)o1', 'CCCCNCCCC', 'c1nnc(C2CC2)o1', 'CCCCN(C)CCCC', 'C1CC1', 'CCCCN(CCCC)Cc1nnco1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nnc(C2CC2)o1.