Hydrochloric Acid → 5-(1-Hydroxy-2-(2,4,5-trifluorophenyl)ethylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione

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Reaction Conditions

Reaction Steps

2,4,5-trifluorophenylacetic acid (30 g), tetrahydrofuran (360 mL), 1,1-carbonyl diimidazole (25.5 g) at about 50° C., and meldrums acid (22.7 g) are combined. The mixture is stirred for about five hours at the same temperature. The reaction mass is then cooled to about 30° C. Isopropyl acetate (180 mL) and water (180 mL) are added and stirred for about 30 minutes. The reaction mass is cooled to about 0° C. and pH is adjusted to about 2.4 using 36% aqueous hydrochloric acid. The organic layer is separated, washed with 0.1 N aqueous hydrochloric acid and distilled off completely. To the residue obtained, n-heptane (140 mL) and isopropyl acetate (70 mL) are charged at about 30° C. and stirred at about 0° C. for about 90 minutes. The separated solid is filtered and washed with a mixture of n-heptane (20 mL) and isopropyl acetate (10 mL). The wet cake is dried at about 50° C. for about 4 hours to afford the title compound. (Yield: 60.1%; purity by HPLC: 98.0%)

Provenance & Evidence