1H-Pyrazol-3-amine, 5-methyl- → 2-methyl-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidine-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

3-Amino-5-methylpyrazole (389 mg) and ethyl (ethoxymethylidene)trifluoroacetoacetate (960 mg) were dissolved in ethanol (10 ml) and stirred for 1.5 hours at 70° C. Conc. hydrochloric acid (1 mg) was added thereto, and the mixture was stirred for additional 1 hour. The mixture was cooled to room temperature and concentrated under reduced pressure. Ethanol (10 ml) and 5 N sodium hydroxide solution (3 ml) were added to the residue and then stirred for 1 hour at 70° C. The mixture was cooled to room temperature, and water was added to the 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 product was dried under reduced pressure to give the title compound (102 mg, Y.:42%) as white crystals.

Provenance & Evidence