Hydrochloric Acid → HCID 21220442, compound

Participants

Reaction Steps

In 18 ml of methylene chloride was suspended 1.80 g of 4-bromo-2,5-difluoro-3-hydroxymethylbenzoic acid and to the suspension were added 1.64 g of triethylamine and 0.84 g of acetic anhydride with ice-cooling, after which the suspension was stirred for one hour. The temperature of the suspension was then elevated to room temperature, at which the mixture was stirred for a further 12 hours. The reaction mixture was added to a mixed solvent of 20 ml of methylene chloride and 50 ml of water and the pH was adjusted to 1 with 6N hydrochloric acid. Thereafter, the organic layer formed was separated, washed with a saturated saline solution and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure. The residue obtained was purified by a column chromatography (eluent: chloroform:ethanol=9:1), to obtain a colorless, oily 3-acetoxymethyl-4-bromo-2,5-difluorobenzoic acid. The oily product obtained was dissolved in 42 ml of anhydrous tetrahydrofuran, and 1.64 g of N,N'-carbonyldiimidazole was added to the solution with ice-cooling. The resulting mixture was stirred at room temperature for one hour. Subsequently, 1.45 g of magnesium ethoxycarbonylacetate was added thereto and the resulting mixture was stirred at the same temperature for 20 hours. The reaction mixture was added to a mixed solvent of 80 ml of ethyl acetate and 100 ml of water, and the pH was adjusted to 1 with 6N hydrochloric acid. Thereafter, the organic layer formed was separated, washed with a saturated saline solution and then dried over anhydrous magnesium sulfate. Thereafter, the solvent was removed by distillation under reduced pressure. The residue thus obtained was purified by a column chromatography (eluent: n-hexane:ethyl acetate=20:1), to obtain 1.32 g of colorless, crystalline ethyl 3-acetoxymethyl-4-bromo-2,5-difluorobenzoylacetate.

Provenance & Evidence