Hydrochloric Acid → 2-(1-Methyl-1H-pyrazol-4-yl)benzenesulfonyl chloride

Participants

Reaction Steps

By the procedure of Example 4, 17.3 g of 1-methyl-4-(2-aminophenyl)-1H-pyrazole prepared in Example 18 was diazotized with 7.2 g of sodium nitrite and 36 ml of concentrated HCl in 104 ml of glacial acetic acid. The diazonium salt suspension was added to a suspension containing 4.3 g of cupric chloride dihydrate, 30 ml of sulfur dioxide and 76 ml of acetic acid. After completion of the reaction and addition of water, the suspension was extracted with 1-chlorobutane. The extraction was dried over sodium sulfate and concentrated in vacuo at less than 40° C. to yield 22 g of crude 2-(1-methyl-1H-pyrazol-4-yl)benzenesulfonyl chloride as an oil.

Provenance & Evidence