Pyridine → 5-Chloro-6-[(3-methylphenyl)sulfanyl]pyrazine-2,3-dicarbonitrile

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Reaction Steps

Pyridine (2.37 g) was mixed rapidly with a solution of 6.00 g of 2,3-dichloro-5,6-dicyanopyrazine in 240 ml of 1,2-dichloroethane. After 15 minutes the well stirred mixture, protected from moisture, was cooled to -30° and 3.72 g of m-thiocresol was added in one portion. The temperature was maintained at -30° for 0.5 hour and then was allowed to return to ambient over the course of 2 hours. The mixture was then washed with water to remove pyridine hydrochloride, dried over MgSO4, and concentrated on a rotary evaporator to a solid residue. The residue was purified by the technique of dry column chromatography using silica gel adsorbent and 1-chlorobutane as solvent and eluent. The yield of pure product was 6.9 g, mp 117°-119°.

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