Hexachloroethane → 3,5-dichloro-N,N-dimethyl-1H-pyrazole-1-sulfonamide

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Reaction Steps

Under a nitrogen atmosphere, a solution of 3-chloro-N,N-dimethyl-1H-pyrazole-1-sulfonamide (1.68 g, 8 mmol) (i.e. the product of Example 12, Step B) in tetrahydrofuran (10 mL) was cooled to −78° C. and then treated with a solution of 2 M n-butyllithium in cyclohexane (4.5 mL, 9 mmol) dropwise. The solution formed a thick precipitate and was allowed to stir for 30 minutes after the addition. To the stirred suspension, a solution of hexachloroethane (2.0 g, 8.5 mmol) in tetrahydrofuran (10 mL) was added dropwise. After 1.5 h the resulting clear solution was warmed to ambient temperature and quenched with the addition of water (20 mL). The reaction mixture was extracted with dichloromethane and dried over MgSO4. The solution was filtered and concentrated under reduced pressure to give 1.97 g of the title compound. This compound was of sufficient purity to use in subsequent reactions.

Provenance & Evidence