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

Participants

Reaction Steps

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.

Provenance & Evidence