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At room temperature and under an atmosphere of protective gas, 43.60 g (0.13 mol) of 2-chloro-3-(4,5-dihydroisoxazol-3-yl)-4-methylsulfonylbenzoyl chloride in 375 ml of anhydrous dioxane and 13.56 g (0.134 mol) of triethylamine in 375 ml of anhydrous dioxane were simultaneously added dropwise to a solution of 12.74 g (0.13 mol) of 5-hydroxy-1-methylpyrazole and 300 ml of anhydrous dioxane. The reaction mixture was stirred at room temperature for 2 hours and then filtered off through silica gel, which was rinsed with dioxane. The eluate was concentrated under reduced pressure to about 500 ml and admixed with 17.94 g (0.13 mol) of dried, finely powdered potassium carbonate. After 6 hours under reflux, the solvent was distilled off under reduced pressure and the residue was taken up in about 700 ml of water. Insoluble components were filtered off and the pH of the filtrate was adjusted to 2-3 by slowly adding 10% strength hydrochloric acid. The precipitate that formed was filtered off with suction. 46.16 g (92% of theory) of 4-[2-chloro-3-(4,5-dihydroisoxazol-3-yl)-4-methylsulfonylbenzoyl]-5-hydroxy-1-methyl-1H-pyrazole were obtained.

1. filtrationfiltered off through silica gel, which
2. washwas rinsed with dioxane
3. concentrationThe eluate was concentrated under reduced pressure to about 500 ml
4. customof dried
5. temperatureAfter 6 hours under reflux
6. distillationthe solvent was distilled off under reduced pressure
7. filtrationInsoluble components were filtered off
8. additionby slowly adding 10% strength hydrochloric acid
9. customThe precipitate that formed
10. filtrationwas filtered off with suction