Potassium Hydroxide → Benzylmalonic acid

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A solution of diethyl [2-n-butyl-1-{(2-chlorophenyl)methyl}-1H-imidazol-5-yl]-2-benzyl-malonate [Example 8(iii)] (5.54 g, 0.0108 mol) in ethanol (75 mL) was treated all at once with a solution of potassium hydroxide (3.65 g, 0.065 mol) in water (50 mL). The resulting mixture was stirred at room temperature for 24 hours, then refluxed for 3 hours. The ethanol was evaporated, water was added to the aqueous product, and the basic solution was extracted with diethyl ether. The aqueous layer was acidified to pH 4 with hydrochloric acid and the product was extracted into ethyl acetate. The dried, concentrated product was crystallized twice from ethyl acetate to give 0.6 g of 2-n-butyl-1-{(2-chlorophenyl)methyl}-1H-imidazol-5-yl]-2-benzyl-malonic acid; mp 165°-166° C.(d). The filtrates from the crystallizations (4.9 g) consisted of additional malonic acid, the propanoic acid derivative and the mono ethyl ester malonate derivative. These are converted to [ 2-n-butyl-1-{(2-chlorophenyl)methyl}-1H-imidazol-5-yl]-2-benzylpropanoic acid by the method described previously.

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