To a stirred solution of 4-methyl-3-nitrobenzonitrile (16.58 g, 102.3 mmol) in 55 mL of N,N-dimethylformamide (DMF) was added N,N-dimethylacetamide (15.24 g, 128.1 mmol). The reaction mixture turned dark red and was subsequently stirred at 110 °C for 3 hours. After completion of the reaction, the solvent was removed under reduced pressure and the residue was dissolved in a mixture of 300 mL of ethanol and 300 mL of acetic acid. The reaction mixture was heated to 60 °C and iron powder (33 g, 594 mmol) was added in batches. The reaction mixture was refluxed for 2 h. After the reaction was completed, it was filtered through a Hyflo pad. Ether was added to the filtrate and the acidic layer was extracted with ether (1×). The ether layers were combined and concentrated in vacuum. The residue was purified by silica gel column chromatography using dichloromethane as eluent to give 7.02 g (48% yield) of 6-cyanoindaha solid.
