Enamino ketone (II) was synthesized by treatment of benzothiophenone (I) with dimethylformamide dimethylacetal. Condensation of (II) with methyl cyanoacetate (III) led to the pyridone-fused tricyclic system (IV), which was further aromatized to (V) using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Ester group hydrolysis in (V) under acidic conditions afforded acid (VI). This was finally decarboxylated in refluxing quinoline in the presence of copper powder.