反应详情

A vigorously stirred solution of 2-chloro-4-(3-methyl-1 H-pyrazol-1-yl)benzoic acid (7.08 g, 30.0 mmol) and 1 N potassium hydroxide (30 mL, 30.0 mmol) in water (200 mL) was heated to between 60–65° C. and treated gradually over ninety minutes with several aliquots of solid potassium permanganate (Total: 49.78 g, 315 mmol, 5.25 equivalents). The mixture was heated for an additional 2.5 hours (4 hours total). After cooling to room temperature, the mixture was filtered and evaporated to a residue. The residue was dissolved in 2 N hydrochloric acid and extracted with ethyl acetate (3×). The combined organic phase was washed with water, dried over anhydrous sodium sulfate, filtered, and the solvent removed in vacuo to yield, after crystallization from a mixture of ethyl acetate-diethyl ether-hexane, the title compound (1.27 g, 4.8 mmol, 16%) as a homogeneous solid, m.p. 260–263° C.;

1. temperatureThe mixture was heated for an additional 2.5 hours (4 hours total)
2. filtrationthe mixture was filtered
3. customevaporated to a residue
4. dissolutionThe residue was dissolved in 2 N hydrochloric acid
5. extractionextracted with ethyl acetate (3×)
6. washThe combined organic phase was washed with water
7. dry with materialdried over anhydrous sodium sulfate
8. filtrationfiltered
9. customthe solvent removed in vacuo
10. customto yield
11. customafter crystallization
12. additionfrom a mixture of ethyl acetate-diethyl ether-hexane