Lithium hydroxide, monohydrate → 2,5-dichloro-4-[3-(4-cyclopropyl-3,4-dihydro-2H-quinoxaline-1-carbonyl)-pyridin-4-yloxy]-benzoic acid

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Reaction Steps

To a suspension of 3.68 g (7.38 mmol) 2,5-dichloro-4-[3-(4-cyclopropyl-3,4-dihydro-2H-quinoxaline-1-carbonyl)-pyridin-4-yloxy]-benzoic acid methyl ester (Example 27) in 40 mL dioxane and 40 mL water were added 0.387 g (9.22 mmol) lithium hydroxide mono hydrate. The reaction mixture was stirred 1.5 hours at room temperature upon which a yellow solution formed. Dioxane was removed by evaporation and the resulting suspension was diluted with 50 mL water and the pH was adjusted to 1 using 10 mL 25% aqueous hydrochloric acid. The resulting suspension was stirred for approx. 2 hours at room temperature, filtered, washed with water and dried under high vacuum to give 3.49 g (97%) of the desired compound as a light brown solid. MS (ESI): m/z=484.3 [M+H]+.

Provenance & Evidence