Pyridine → HCID 18690747, compound

Participants

Reaction Conditions

Reaction Steps

65 ml (0.8 mol) of pyridine and then 80 ml (0.48 mol) of trifluoromethanesulfonic acid anhydride are added dropwise at 0-5° C. to a solution of 129 g (0.3 mol) of 3-(4-chloro-2-fluoro-5-hydroxyphenyl)-4-methyl-5-(methylthio)-1-methyl-[1H]-pyrazole (approx. 70%) (Example P9) in 1.2 liters of 1,4-dioxane. After being stirred for 30 minutes at 0-5° C. and then at 22° C. overnight, the reaction mixture is concentrated to approximately 1/3 of its original volume by evaporation, poured into a mixture of ice, water and hydrochloric acid, extracted with MTBE, washed with water and concentrated by evaporation. After purification of the crude product by silica gel chromatography, 87.7 g (70% of the theoretical yield) of the desired compound are isolated in the form of crystals having a melting point of 54-56° C.

Provenance & Evidence