['CO', 'CCn1c(=C(C#N)C#N)s/c(=C/c2csc(Br)c2)c1=O', 'CCOC', 'N#CC(C#N)=c1[nH]c(=O)/c(=C\\c2csc(Br)c2)s1']
The Murcko scaffold (minmal number of connected rings) of <smiles></smiles> is C=c1[nH]c(=O)/c(=C\c2ccsc2)s1.