Réaction #41169

Équation de réaction

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

Rendement 52.6%

Solvants

ethanol

Conditions de réaction

Traitement

1. 1
   TempératureAfter cooling to room temperature
2. 2
   Autrethe reaction mixture was partitioned between methylene chloride and water
3. 3
   LavageThe organic phase was washed with water and brine
4. 4
   ExtractionEach aqueous phase was back extracted with a second portion of methylene chloride
5. 5
   Séchagedried over sodium sulfate
6. 6
   Concentrationconcentrated in vacuo
7. 7
   AutrePurification by flash chromatography
8. 8
   Lavageeluting with a 10-40% ethyl acetate-hexanes

Mode opératoire

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).

Source