Lithium Hydroxide → 7-[5-(2-n-Propyl-3-hydroxy-4-acetylphenoxy)pentoxy]-8-n-propylchroman-2-carboxylic acid

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Reaction Steps

5 g (9.8 mmole) of the methyl ester from Example 6 was placed in a 250 ml round bottom flask and warmed in 100 ml of methyl alcohol to effect dissolution. After cooling to room temperature, 7.5 ml of 2M LiOH was added and the reaction mixture stirred for 3 hours. Solvent was stripped on the rotary evaporator and water added. The solution was acidified to pH 2 with hydrochloric acid, and the resultant gummy mass was extracted with ethyl acetate-ether, washed once with water then with brine, and dried over Na2SO4. After filtration, the solvent was removed on the rotary evaporator under vacuum at room temperature. Recrystalization form ethyl alcohol gave 3.84 g (79% yield), mp 66°-68° C., of the title compound. Calc: C, 69.86; H, 7.76; Found: C, 70.05; H, 7.68.

Provenance & Evidence