反应详情

A stirred slurry of 0.35 gram (0.0009 mole) of ethyl 2-chloro-3-[4-cyano-1-(2,3,4-trichlorophenyl)-1H-pyrazol-5-yl]propionate and 0.24 gram (0.002 mole) of potassium carbonate in 35 mL of 50% aqueous ethanol was heated at reflux for one hour. The reaction mixture was then cooled and concentrated under reduced pressure, leaving a residue. The residue was dissolved in water, and the solution was washed once with methylene chloride. The aqueous layer was stirred and acidified by the dropwise addition of concentrated hydrochloric acid. Upon acidification, the mixture was stirred for one hour, and the resultant solid was collected by filtration. The solid was dried, yielding 0.21 gram of 3-[4-cyano-1-(2,3,4-trichlorophenyl)-1H-pyrazol-5-yl]acrylic acid; m.p. 215°-219° C. A small sample was recrystallized from ethanol and water to raise the m.p. to 226.5°-228.5° C. The nmr spectrum was consistent with the proposed structure.

1. temperatureat reflux for one hour
2. temperatureThe reaction mixture was then cooled
3. concentrationconcentrated under reduced pressure
4. customleaving a residue
5. washthe solution was washed once with methylene chloride
6. additionacidified by the dropwise addition of concentrated hydrochloric acid
7. stirringUpon acidification, the mixture was stirred for one hour
8. filtrationthe resultant solid was collected by filtration
9. customThe solid was dried