反应 #41164

反应方程式

Cyclopentyl-hydrazine hydrochloride

ethyl (ethoxymethylene)-cyanoacetate

sodium acetate

→

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

收率 79.3%

溶剂

ethanol

反应条件

后处理

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

实验过程

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).

来源