2-[3-Chloro-4-(4-chloropyrazol-1-yl)phenyl]propionic acid benzyl ester → 2-[3-Chloro-4-(4-chloropyrazol-1-yl)phenyl]propionic acid

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Reaction Steps

375 mg (1 mmole) of 2-[3-chloro-4-(4-chloropyrazol-1-yl)phenyl]propionic acid benzyl ester are hydrogenolyzed in the presence of 50 mg of 10% palladium/activated charcoal at room temperature and at atmospheric pressure in a mixture of 100 ml of ethyl acetate and 10 ml of glacial acetic acid in a rotary hydrogenation apparatus until the theoretical amount of hydrogen has been absorbed. Filtration from the catalyst is effected, the filtrate is concentrated in a vacuum, and the residue is dissolved in a 1 N solution of sodium hydroxide. The resulting aqueous solution is extracted with benzene; acidification is effected with 1 N hydrochloric acid, followed by extraction again with benzene. The organic phase is dried and concentrated to yield 230 mg (80.7% of theory) of 2-[3-chloro-4-(4-chloropyrazol-1-yl)phenyl]propionic acid (m.p. 102° to 103° C.).

Provenance & Evidence