Hydrochloric Acid → (3,5-Dimethyl-1-{4-[(E)-2-(4-trifluoromethyl-phenyl)-vinyl]-benzyl}-1H-pyrazol-4-yl)-acetic acid

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Reaction Conditions

Reaction Steps

A solution of [1-(4-bromo-benzyl)-3,5-dimethyl-1H-pyrazol-4-yl]-acetic acid methyl ester (intermediate 12.1.1, 500 mg, 1.5 mmol), 4-(trifluoromethyl)styrene (0.24 ml, 1.6 mmol) and diisopropylethylamine (0.38 ml, 2.2 mmol) in 10 ml dimethylformamide was degassed, and Pd(II) acetate (33 mg, 0.15 mmol) and tri(o-tolyl)phosphine (45 mg, 0.15 mmol) were added to the solution under argon. The mixture was heated for 4 h at 90° C. and stirred for 12 h at room temperature. The mixture was poured into water and extracted twice with ethyl acetate. The organic layer was separated, dried over MgSO4 and the solvent was evaporated under reduced pressure. The residue was purified by MPLC (silica gel, CH2Cl2/methanol 99:1). Saponification: The ester intermediate (530 mg, 1.24 mmol) was dissolved in 5 ml dioxane and aqueous NaOH solution (2.5 ml, 1 M). After stirring for 1 h and dilution with water, aqueous HCl solution (2.6 ml, 1 M) was added. The mixture was extracted with ethyl acetate, the organic layer was dried with MgSO4 and evaporated under reduced pressure. The residue was purified by MPLC (silica gel, CH2Cl2/methanol 91:9) and preparative reversed phase HPLC (gradient of methanol in water+0.1% NH3).

Provenance & Evidence