Hydrochloric Acid → (2E)-3-[4-(4-fluorophenyl)-1-methyl-1H-pyrazol-5-yl]acrylic acid

Sodium hydride (60% in oil, 60 mg) was added to a mixture of 4-(4-fluorophenyl)-1-methyl-1H-pyrazole-5-carbaldehyde (168 mg), ethyl diethylphosphonoacetate (400 mg) and N,N-dimethylformamide (3 ml) at 0° C. and the mixture was stirred at room temperature for 15 min. The reaction mixture was poured into a 1N aqueous hydrochloric acid solution and the mixture was extracted with ethyl acetate. The ethyl acetate layer was concentrated and the residue was dissolved in a mixture of 6N hydrochloric acid (18 ml) and acetic acid (2 ml). The mixture was stirred for 1 hr. with heating under reflux. The reaction mixture was concentrated and poured into water. 1N Sodium hydroxide was added for neutralization. The precipitated solids were collected by filtration, washed with water, and dried to give (2E)-3-[4-(4-fluorophenyl)-1-methyl-1H-pyrazol-5-yl]acrylic acid (159 mg, 78%) as colorless crystals.

1. extractionthe mixture was extracted with ethyl acetate
2. concentrationThe ethyl acetate layer was concentrated
3. dissolutionthe residue was dissolved in a mixture of 6N hydrochloric acid (18 ml) and acetic acid (2 ml)
4. stirringThe mixture was stirred for 1 hr
5. temperaturewith heating
6. temperatureunder reflux
7. concentrationThe reaction mixture was concentrated
8. additionpoured into water
9. addition1N Sodium hydroxide was added for neutralization
10. filtrationThe precipitated solids were collected by filtration
11. washwashed with water
12. customdried

ORD record

ord-a3d12dfc2d4d4a6f9702605c13b20559

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07423159B2