To a 100 mL four-necked flask under nitrogen protection was added nickel ryenne (12.6 g), N,N-dimethylacetamide (30 mL), morpholine (1.36 mL, 15.6 mmol), and 2,2'-dithiobis[5-(2-fluorophenyl)-1H-pyrrole-3-carbonitrile] (4.50 g, 10.4 mmol) to a 15 mL solution of N,N-dimethylacetamide (15 mL) solution. The reaction mixture was heated at reflux at 105 °C for 5.5 hours. After completion of the reaction, the mixture was cooled, the catalyst was removed by filtration, and the filter cake was washed sequentially with N,N-dimethylacetamide and ethyl acetate. Liquid-liquid partitioning was carried out by adding 5% brine to the filtrate and washing solution. The aqueous layer was extracted three times with ethyl acetate. The organic layers were combined, washed with 5% brine and concentrated to dryness under reduced pressure. Ethanol (22.5 mL) was added to the residue and heated to dissolve. Water (45 mL) was added to induce crystallization. The slurry was heated to reflux for 1 hour, then cooled to room temperature and an ice-water mixture was added. Crystals were collected by filtration and washed with an ice-cooled water/ethanol (1:2, 10 mL) mixture. The crystals were dried under reduced pressure at 50 °C to afford the title compound 5-(2-fluorophenyl)-1H-pyrrole-3-carbonitrile (3.45 g, 85% yield). The product was confirmed by 1H-NMR (DMSO-d6, TMS, 300 MHz), mass spectrometry (EI) and elemental analysis.
