反応 #41169

反応方程式

Cyclopentyl-hydrazine hydrochloride

cyclopentyl-hydrazine hydrochloride

2-dimethylaminomethylene-4,4,4-trifluoro-3-oxo-butyric acid ethyl ester

sodium acetate

→

1-cyclopentyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester

収率 52.6%

溶媒

ethanol

反応条件

後処理

1. 1
   温度After cooling to room temperature
2. 2
   その他the reaction mixture was partitioned between methylene chloride and water
3. 3
   洗浄The organic phase was washed with water and brine
4. 4
   抽出Each aqueous phase was back extracted with a second portion of methylene chloride
5. 5
   乾燥dried over sodium sulfate
6. 6
   濃縮concentrated in vacuo
7. 7
   その他Purification by flash chromatography
8. 8
   洗浄eluting with a 10-40% ethyl acetate-hexanes

実験手順

Cyclopentyl-hydrazine hydrochloride (0.250 g, 1.83 mmol, Example 64, Step 2), 2-dimethylaminomethylene-4,4,4-trifluoro-3-oxo-butyric acid ethyl ester (0.403 g, 1.68 mmol) and anhydrous sodium acetate (0.163 g, 1.99 mmol) were combined in ethanol (2.5 mL) and heated at 70° C. for 17 hours. After cooling to room temperature, the reaction mixture was partitioned between methylene chloride and water. The organic phase was washed with water and brine. Each aqueous phase was back extracted with a second portion of methylene chloride. The two organic phases were combined, dried over sodium sulfate and concentrated in vacuo. Purification by flash chromatography, eluting with a 10-40% ethyl acetate-hexanes gradient, yielded 1-cyclopentyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (0.244 g, 52%). Mass spectrum: m/z: 277.1 (M+H).

出典