Dimethylformamide → 1-(4-Methyl-2-nitrophenyl)piperidine

Piperidine (660 μl, 6.66 mmol, commercially available product) was added at room temperature to an N,N-dimethylformamide (DMF; 1 ml) solution of 4-chloro-3-nitrotoluene (358 mg, 2.08 mmol, commercially available product). The resulting mixture was stirred at 100° C. for 17 hours. The mixture was cooled to room temperature, and then water was added thereto. The resulting mixture was extracted three times with ethyl acetate. The obtained organic layer was washed with a saturated sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (50 g, hexane/ethyl acetate=50/1). Thus, 1-(4-methyl-2-nitrophenyl)piperidine (212 mg, 46.2%) was yielded as a colorless oily material.