Lithium Hydroxide → 1-{3-[(E)-2-(4-Chloro-phenyl)-vinyl]-phenyl}-3,5-diethyl-1H-pyrazole-4-carboxylic acid

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Reaction Steps

A solution of 1.78 g (4.5 mmol) of 1-{3-[(E)-2-(4-chloro-phenyl)-vinyl]-phenyl}-3,5-diethyl-1H-pyrazole-4-carboxylic acid methyl ester in 100 ml of THF/MeOH (1:1) was treated with 11.3 ml of lithium hydroxide solution (1 M in water) at RT and then stirred at reflux (boiling temperature=80° C.) for 60 hours. The reaction mixture was then cooled to RT and evaporated. The residue was partitioned between water and CH2Cl2, acidified with HCl (2N) to pH 1-2 and extracted twice with CH2Cl2. The organic phases were washed with water, dried over magnesium sulfate, filtered and evaporated to give 1.69 g of crude title compound as light yellow solid. MS: 379.2 ([M−H]−, 1 Cl).

Provenance & Evidence