Reaction #41104

Reaction equation

t-butylhydrazine hydrochloride salt

ethyl (ethoxymethylene)-cyanoacetate

sodium acetate

→

5-amino-1-tert-butyl-1H-pyrazole-4-carboxylic acid ethyl ester

Yield 77.0%

Solvents

ethanol

Conditions

Workup

1. 1
   Temperaturerefluxed for 16 hours
2. 2
   ExtractionThe separated aqueous phase was extracted three times with dichloromethane
3. 3
   WashThe combined organic phases were washed successively with water and saturated brine solution
4. 4
   Dryingdried with sodium sulfate
5. 5
   OtherThe solvent was removed in vacuo

Procedure

A solution containing t-butylhydrazine hydrochloride salt (10 g, 80.3 mmol), ethyl (ethoxymethylene)-cyanoacetate (13.6 g, 80.4 mmol), and anhydrous sodium acetate (8.2 g, 100 mmol) in 100 mL ethanol was stirred and refluxed for 16 hours. The solution was poured into ice-water. The separated aqueous phase was extracted three times with dichloromethane. The combined organic phases were washed successively with water and saturated brine solution and dried with sodium sulfate. The solvent was removed in vacuo to give 5-amino-1-tert-butyl-1H-pyrazole-4-carboxylic acid ethyl ester (13 g, 77%).

Source