| Use | 3-methyl-1-(3, 4-dimethylphenyl)-2-pyrazoline-5-one is also called 2-(3, 4-dimethylphenyl)-1, 2-dihydro-5-methyl-3H-pyrazoline-3-one, which is a pharmaceutical intermediate, can be used to prepare Aiqubopa. Etruppa was approved by the FDA in November 2008 for the treatment of patients with chronic idiopathic thrombocytopenic purpura (ITP) after glucocorticoid drugs, immunoglobulin therapy or splenectomy. On November 19, 2012, the small molecule thrombopoietin receptor agonist eltrombopag (trade name: Promacta) was approved for the treatment of thrombocytopenia in patients with chronic hepatitis C. |
| preparation | at room temperature, mix 100g(578mmol)3.4-dimethylphenylhydrazine hydrochloride and 600ml absolute ethanol, add 62.8g(923mmol) sodium ethoxide in batches, and stir for 1 hour until the materials are completely dissolved. Raise the temperature to 40 degrees, slowly add 84g(646mmol) of ethyl acetoacetate dropwise, and stir for 30 minutes. Open heating to reflux state, heat preservation reaction 24 hours to TLC tracking reaction to no raw material point. Stop heating and remove most of the ethanol solvent under reduced pressure. The resulting brown viscous liquid. Add 300ml of ethyl acetate, then add 300ml of tap water in batches, stir well, extract by liquid, and dry the ethyl acetate phase with anhydrous sodium sulfate to remove water. The solvent was spirled under reduced pressure to obtain a light yellow oily solid, and 400ml methyl tert-butyl ether dispersion system was added. Filtration, the filter cake was leached with methyl tert-butyl ether, and air drying to obtain 3-methyl-1-(3, 4-dimethylphenyl)-2-pyrazolin-5-one 91g(450mmol) white powder solid. 1HNMR(400MHz,DMSO-d6):δ11.30(brs,1H),7.49(d,1H),7.43(dd,1H),7.14(d,1H),5.31(s,1H),2.20(s,3H),2.22(s,3H),2.08(s,3H). |
