Reacción #41164

Ecuación de reacción

Cyclopentyl-hydrazine hydrochloride

ethyl (ethoxymethylene)-cyanoacetate

sodium acetate

→

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

Rendimiento 79.3%

Disolventes

ethanol

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaAfter cooling to room temperature
2. 2
   Otroethanol was removed in vacuo
3. 3
   Otrothe residue was partitioned between methylene chloride and water
4. 4
   LavadoThe organic phase was washed sequentially with water and brine
5. 5
   ExtracciónEach aqueous phase was back extracted with a single portion of methylene chloride
6. 6
   Secadodried over sodium sulfate
7. 7
   Concentraciónconcentrated
8. 8
   OtroPurification by flash chromatography
9. 9
   Lavadoeluting with 10-40% EtOAc/hexanes

Procedimiento

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).

Fuente