Azobisisobutyronitrile → HCID 23444990, Verbindung

Beteiligte Stoffe

Reaktionsschritte

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 (1.2g, 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, of 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+).

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