反応 #41164

反応方程式

Cyclopentyl-hydrazine hydrochloride

ethyl (ethoxymethylene)-cyanoacetate

sodium acetate

→

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

収率 79.3%

溶媒

ethanol

反応条件

後処理

1. 1
   温度After cooling to room temperature
2. 2
   その他ethanol was removed in vacuo
3. 3
   その他the residue was partitioned between methylene chloride and water
4. 4
   洗浄The organic phase was washed sequentially with water and brine
5. 5
   抽出Each aqueous phase was back extracted with a single portion of methylene chloride
6. 6
   乾燥dried over sodium sulfate
7. 7
   濃縮concentrated
8. 8
   その他Purification by flash chromatography
9. 9
   洗浄eluting with 10-40% EtOAc/hexanes

実験手順

Cyclopentyl-hydrazine hydrochloride (1.000 g; 7.32 mmol), ethyl (ethoxymethylene)-cyanoacetate (1.026 g, 6.61 mmol) and anhydrous sodium acetate (0.644 g, 7.85 mmol) were combined in ethanol (10 mL) and heated at 70° C. for 20 hours. After cooling to room temperature, ethanol was removed in vacuo and the residue was partitioned between methylene chloride and water. The organic phase was washed sequentially with water and brine. Each aqueous phase was back extracted with a single portion of methylene chloride. The two organic phases were combined, dried over sodium sulfate and concentrated. Purification by flash chromatography, eluting with 10-40% EtOAc/hexanes yielded 5-amino-1-cyclopentyl-1H-pyrazole-4-carboxylic acid ethyl ester (1.170 g, 73%). Mass spectrum: m/z: 224.1 (M+H).

出典