['CN', 'CCCN(CC=O)Cc1nnc(C2CC2)o1', 'CCC', 'CNC(=O)CNCc1nnc(C2CC2)o1', 'CNC(C)=O', 'CCCNCc1nnc(C2CC2)o1', 'Cc1nnc(C2CC2)o1', 'CCCNCC(=O)NC', 'c1nnc(C2CC2)o1', 'CCCN(C)CC(=O)NC', 'C1CC1', 'CCCN(CC(=O)NC)Cc1nnco1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1nnc(C2CC2)o1.