Trifluoroacetic acid → ethyl 5-amino-1-(4-ethoxy-2,6-difluorobenzyl)-4-methyl-1H-pyrazole-3-carboxylate

2.01 g potassium (2Z)-3-cyano-1-ethoxy-1-oxobut-2-en-2-olate (10.9 mmol, 1.0 eq.) were dissolved in dioxane at rt and 1.34 mL trifluoroacetic acid (17.4 mmol, 1.6 eq.) were added within 2 minutes. The slurry was stirred for 10 minutes and 3.00 g (4-ethoxy-2,6-difluorobenzyl)hydrazine dihydrochloride (10.9 mmol, 1.0 eq.) were added. The reaction mixture was stirred at 130° C. for 3 hours. The resulting solid was filtered off and washed rinsed with dioxane. The filtrate was partitioned between ethyl acetate and water. The aqueous phase was washed with ethyl acetate three times. The collected organic solutions were washed with brine, dried over a silicon filter, concentrated in vacuo and purified by flash chromatography: 1.10 g (2.42 mmol, 22%) of a 71% pure target compound.

1. stirringThe reaction mixture was stirred at 130° C. for 3 hours
2. filtrationThe resulting solid was filtered off
3. washwashed
4. washrinsed with dioxane
5. customThe filtrate was partitioned between ethyl acetate and water
6. washThe aqueous phase was washed with ethyl acetate three times
7. washThe collected organic solutions were washed with brine
8. customdried over a silicon
9. filtrationfilter
10. concentrationconcentrated in vacuo
11. custompurified by flash chromatography

ORD record

ord-65d4bc075de044fd89e2365fa25c3a31

Source dataset

uspto-grants-2016_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09422268B2