Dimethylformamide → 4-(2-fluorophenyl)-1H-pyrazole

Temperatur

70 °C

11.08 ml of N,N-dimethylformamide was slowly added dropwise to 11.03 ml of POCl3 were at 0-5° C. while stirring and, after about 5 minutes a solution of 2-fluorophenylacetic acid (6 g, 38.9 mmol) in 20 ml of N,N-dimethylformamide was added dropwise. The mixture was then heated at 70° C. for about 17 hours. The mixture was subsequently quenched with ice-water and the mixture was made alkaline by adding NaOH. The resulting solid was filtered off, the solution was extracted with dichloromethane, and the organic phase was dried and concentrated. The oil obtained in this way was directly dissolved in 50 ml of ethanol. 7.3 ml of hydrazine hydrate were added, and the reaction mixture was heated at 55° C. for 3 hours. After the reaction was complete, the solvent was evaporated and the remaining solid was stirred with water and then dried. 2.65 g of 4-(2-fluorophenyl)-1H-pyrazole were obtained.

1. customwere at 0-5° C.
2. additionwas added dropwise
3. customThe mixture was subsequently quenched with ice-water
4. additionby adding NaOH
5. filtrationThe resulting solid was filtered off
6. extractionthe solution was extracted with dichloromethane
7. customthe organic phase was dried
8. concentrationconcentrated
9. customThe oil obtained in this way
10. temperaturethe reaction mixture was heated at 55° C. for 3 hours
11. customthe solvent was evaporated
12. customdried

ORD-Eintrag

ord-907dcb6cd7ef4986816ccfa17dc9f1b9

Quelldatensatz

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09139557B2