['CC1(C)CNCC2(CCCC2)O1', 'CCCc1ccn2ncnc2n1', 'CCC', 'CC1(C)CN(c2ccnc3ncnn23)CC2(CCCC2)O1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is c1cc(N2CCOC3(CCCC3)C2)n2ncnc2n1.