1,1,2,2-Tetrachloroethylsulfenyl chloride → 5-Cyano-1-(2,6-dimethylphenyl)-3-(1,1,2,2-tetrachloroethanesulfenyl)uracil

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Reaction Steps

To an ice cold solution of 1.60 g (0.04 mol) of NaOH in 45 ml of water is added 9.64 g (0.04 mol) of 5-cyano-1-(2,6-dimethylphenyl)uracil, obtained as in Example 1. After dissolution, 50 ml of ice cold dichloromethane is added, followed by a solution of 9.36 g (0.04 mol) of 1,1,2,2-tetrachloroethanesulfenyl chloride (prepared by the method of U.S. Pat. No. 3,395,180) in 15 ml of dichloromethane. The mixture is stirred for 30 min at 4°, after which time 50 mg of triethylbenzylammonium chloride is added and stirring is continued for another 30 min at 4°. The aqueous layer is separated and discarded. The dichloromethane solution is dried and stripped at aspirator pressure. The unreacted sulfenyl chloride is then removed by trituration with pentane/dichloromethane (4:1). The resultant crude product is purified by slurrying at 30° in 60 ml of ethanol-free chloroform, allowed to cool to RT and filtered. To the filtrate is added hexane to the cloud point, and the mixture is then filtered to yield 5-cyano-1-(2,6-dimethylphenyl)-3-(1,1,2,2-tetrachloroethanesulfenyl)uracil, m.p. 180°-183°.

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