['CCCN', 'O=CCn1c(-c2cccs2)noc1=O', 'CCC', 'NC(=O)Cn1c(-c2cccs2)noc1=O', 'CCCNC(C)=O', 'O=c1[nH]c(-c2cccs2)no1', 'c1ccsc1', 'CCCNC(=O)Cn1cnoc1=O']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is O=c1[nH]c(-c2cccs2)no1.