The reaction was cooled to room temperature. The crude material was purified by flash column chromatography (0 -50% ethyl acetate in cyclohexane) to yield the title compound (0.92 g, 56% Step A: 2-Chloro-4-mercaptobenzonitrile To 2-chloro-4-fluorobenzonitrile (0.50 g, 3.2 mmol) was added sodium sulphide (0.27 g, 3.5 mmol) and in DMF (2.5 mL) and the reaction was stirred at room temperature for 2 hrs. 1 M Sodium hydroxide was added and the mixture washed with dichloromethane (5 mL). The aqueous layer was acidified to pH 1-2 with 1 M hydrogen chloride solution (2 mL) and extracted with dichloromethane (2 x 5 mL). The combined organic layers were washed with brine (5 mL), dried over magnesium sulfate, filtered and concentrated under reduced pressure to provide a crude residue. To the residue was added 10 % hydrogen chloride solution (2 mL) and the mixture was cooled with an ice-water bath. Zinc dust (2.00 g, 30.6 mmol) was added and the mixture was stirred for 1 hour. Ethyl acetate (5 mL) was added and the mixture was stirred for an additional 30 min. The organic layer was separated and washed with water (10 mL) and brine (10 mL), dried over magnesium sulfate, filtered and concentrated under reduced pressure to provide the desired product as an orange oil (0.48 g, 88% Step B: 4-(((5,6-Dimethoxypyrazin-2-yl)methyl)thio)phthalonitrile