['N#CCO', 'CCc1nc(C)c2c(C)c(C=O)sc2n1', 'CC#N', 'CCc1nc(C)c2c(C)c(C(=O)O)sc2n1', 'N#CCOC=O', 'CCc1nc(C)c2c(C)csc2n1', 'CC', 'Cc1ncnc2sc(C(=O)OCC#N)c(C)c12']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1ncc2ccsc2n1.