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

Temperature

70 °C

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.

1. stirringthe mixture was stirred for additional 1 hour
2. temperatureThe mixture was cooled to room temperature
3. concentrationconcentrated under reduced pressure
4. additionEthanol (10 ml) and 5 N sodium hydroxide solution (3 ml) were added to the residue
5. stirringstirred for 1 hour at 70° C
6. temperatureThe mixture was cooled to room temperature
7. additionwater was added to the mixture which
8. washwas then washed with ethyl acetate
9. addition2 N Hydrochloric acid was added to the aqueous phase until it
10. customprecipitated crystals
11. filtrationwere collected by filtration
12. washwashed with water and n-hexane
13. customThe product was dried under reduced pressure

ORD record

ord-71317cfbd6c740068595a2333d506f0b

Source dataset

uspto-grants-2008_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07345180B2