Chlorine → 5-(5-Chloro-3-fluoro-2-pyridyl)-4-chloro-2-methyl-[2h]-pyrazole-3-carboxylic acid ethyl ester

Participants

Reaction Steps

22.9 g of 5-(5-chloro-3-fluoro-2-pyridyl)-2-methyl-[2H]-pyrazole-3-carboxylic acid ethyl ester (Example P19) are introduced together with 19.9 g of sodium acetate into 300 ml of glacial acetic acid at a temperature of 65° C. With stirring, 6.3 g of chlorine gas are passed over the solution at that temperature in the course of 1 hour. The reaction mixture is then poured into 2.5 liters of ice-water and subsequently stirred for 20 minutes. The resulting precipitate is filtered off, washed with ice-water and then dried in vacuo at 50° C. 24.4 g of the desired title compound are obtained in the form of a yellow solid having a melting point of 77-79° C.

Provenance & Evidence