反应详情

A solution of 1-(3,4-dichloro-phenyl)-3-methyl-1H-pyrazole (1.4 g, 6.1 mmol) in carbon tetrachloride was treated with N-bromosuccinimide (1.2 g, 6.8 mmol) and a catalytic amount of 2,2′azobis-(isobutyronitrile). The mixture was refluxed for 2 h, cooled, filtered and evaporated. The oily residue was dissolved in DMF (10 ml) and added to a solution of sodium hydride (0.32 g, 7.3 mmol, cf example 1) deprotonated 2-metylimidazole (0.60 g, 7.3 mmol) in DMF (10 ml). After stirring for 12 h at rt all volatiles were removed in vacuo and the residue obtained was dissolved in AcOEt. The organic phase was washed with H2O (3×), dried (Na2SO4) and concentrated. Purification by chromatography [silica, elution with gradient CH2Cl2 to 60% (CH2Cl2/MeOH/aq. NH4OH=90:10:1)] gave the free base of the title compound (0.98 g, 52%) as a light brown oil. After treatment with a solution of HCl in MeOH followed by addition of Et2O the title compound was isolated as a white crystalline material. Mp. 204-205° C. (MeOH/Et2O), MS: m/e=306 (M+).

1. temperatureThe mixture was refluxed for 2 h
2. temperaturecooled
3. filtrationfiltered
4. customevaporated
5. dissolutionThe oily residue was dissolved in DMF (10 ml)
6. customwere removed in vacuo
7. customthe residue obtained
8. washThe organic phase was washed with H2O (3×)
9. dry with materialdried (Na2SO4)
10. concentrationconcentrated
11. customPurification
12. washby chromatography [silica, elution with gradient CH2Cl2 to 60% (CH2Cl2/MeOH/aq. NH4OH=90:10:1)]