Sulfuryl chloride → 3-Amino-4-chloro-1-methyl-5-trifluoromethylpyrazole

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Reaction Steps

2.0 g (12.1 mmole) 3-Amino-1-methyl-5-trifluoromethylpyrazole in 20 ml acetonitrile was treated with 1.8 g (13.3 mmole) sulfuryl chloride and the mixture stirred for 2 hours at room temperature. It was poured into aqueous saturated sodium hydrogen carbonate, extracted with ethyl acetate, dried over sodium sulfate and concentrated. 2.24 g 3-Amino-4-chloro-1-methyl-5-trifluoromethylpyrazole was obtained, which was treated without further purification as described under 2 (Example 1) to give 4-chloro-3-hydrazino-1-methyl-5-trifluoromethylpyrazole.

Provenance & Evidence