Nitrogen → 1-Methyl-1H-pyrazole-3-sulfonyl chloride

Participants

Reaction Steps

The N-methylpyrazole sulfonyl chloride was prepared by adding N-methylpyrazole to chilled (0° C.) chlorosulfonic acid. The reaction mixture was allowed to warm to room temperature and then heated to 100° C. overnight under a stream of N2. The reaction mixture was then cooled to room temperature and chilled to 0° C. To this solution was added thionyl chloride (2.5 eq.) and the reaction was stirred at room temperature for 30 min., then warmed to 70° C. for two hours. The reaction was cooled to room temperature and then chilled in an ice bath. Water and ice were slowly added to the reaction mixture to precipitate a white solid which was collected by filtration. The desired sulfonyl chloride was washed with cold water and hexane.

Provenance & Evidence