反应详情

A mixture of 6.25 g of (1-methylpyrazol-5-yl)-(2,3-dichloro-4,5-dimethoxyphenyl)-methanone and 70 ml of aqueous 47% hydrobromic acid is refluxed for 3 hours and the reaction mixture is evaporated to remove solvent. The residue is dissolved in aqueous 10% sodium hydroxide solution and the solution is adjusted to pH 3-4 by addition of acetic acid. The mixture is extracted with ethyl acetate. The extract is washed with an aqueous saturated sodium chloride solution, dried and evaporated to remove solvent under reduced pressure. The residue is crystalized from isopropyl ether and the crystals are collected by filtration to give 4.77 g of (1-methylpyrazol-5-yl)-(2,3-dichloro-4,5-dihydroxyphenyl)-methanone. Yield: 84%

1. temperatureis refluxed for 3 hours
2. customthe reaction mixture is evaporated
3. customto remove solvent
4. dissolutionThe residue is dissolved in aqueous 10% sodium hydroxide solution
5. additionthe solution is adjusted to pH 3-4 by addition of acetic acid
6. extractionThe mixture is extracted with ethyl acetate
7. washThe extract is washed with an aqueous saturated sodium chloride solution
8. customdried
9. customevaporated
10. customto remove solvent under reduced pressure
11. customThe residue is crystalized from isopropyl ether
12. filtrationthe crystals are collected by filtration