Hydrochloric Acid → 3-(4-Pentylphenacyl) benzonitrile

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Reaction Steps

First, 3-cyanophenylacetic acid (3 g, 0.019 mol) is heated under reflux in thionyl chloride (50 ml) for 90 minutes. The excess thionyl chloride is then removed by distillation and the residual acid chloride added in one portion to a solution. 1-phenylpentane (2.76 g, 0,019 moles) in methylene chloride (10 ml). Anhydrous aluminum chloride (2.98 g) is added in small portions over 10 minutes. The reaction mixture is then heated under reflux for 1 hour, cooled and poured into a mixture of ice water (250 ml) and concentrated hydrochloric acid (50 ml). The mixture is extracted with ether (2×100 ml). The ether extracts are dried over magnesium sulfate, filtered, and evaporated to dryness. The residue is chromatographed on silica (hexane: ethyl acetate at 90:10 ) to yield 3-(4-pentylphenacyl) benzonitrile (1.13 g, m.p. 73° C.). This nitrile is heated under reflux in a mixture of 75% sulfuric acid (8 g) and acetic acid (8 g) for 90 minutes. The reaction mixture is then diluted with water (100 ml) and extracted with ether (2×75 ml). The ether extracts are dried over magnesium sulfate, filtered, and evaporated to dryness. The residue is recrystallized from heptane to provide 3-(4-pentylphenacyl)benzoic acid (0.97 g), m.p. 109°-111° C., which was identified by IR and NMR spectroscopy.

Provenance & Evidence