Ethyl 2-acetylacetoacetate → 2,5,7-Trimethylpyrazolo[1,5-a]pyrimidine-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

3-Amino-5-methylpyrazole (970 mg) and ethyl diacetoacetate (1.7 g) were dissolved in acetic acid (5 ml) and stirred at 120° C. for 3 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. Ethanol (5 ml) and 5 N sodium hydroxide solution (2 ml) were added to the residue and stirred at 70° C. for 1 hour. The reaction mixture was cooled to room temperature, and water was added to the reaction mixture which was then washed with ethyl acetate. 2 N Hydrochloric acid was added to the aqueous phase until it became acidic, and precipitated crystals were collected by filtration and washed with water and n-hexane. The crystals were dried under reduced pressure to give the title compound (1.6 g, Y.:80%) as white crystals.

Provenance & Evidence