Acetic Anhydride → HCID 66672660, compound

Participants

Reaction Steps

(2R)-2-Amino-2-methyl-4-(1-methylpyrrol-2-yl)butan-1-ol 1/2 D-(−)-tartrate (3.98 g, 15.5 mmol) obtained in Reference example 1 (1 g) was suspended in a mixture of methylene chloride (50 mL) and water (12.5 mL) and an aqueous sodium hydroxide solution (3.20 g of 97% sodium hydroxide was dissolved in 12.5 mL of water) was added thereto, followed by stirring of the mixture at room temperature for 20 minutes. Methylene chloride was added to the reaction mixture to separate it. The thus obtained organic phase was separated and dried over anhydrous sodium sulfate. After filtration, the solvent was evaporated under reduced pressure and the residue was dissolved in methylene chloride (78 mL). Triethylamine (21.5 mL, 155 mmol), acetic anhydride (7.30 mL, 77.4 mmol) and 4-dimethylaminopyridine (0.189 g, 1.55 mmol) were added thereto and the mixture was stirred at room temperature for 1 hour. Methanol was added thereto to stop the reaction and the solvent was evaporated under reduced pressure. Ethyl acetate and water were added to the residue to separate it. The thus obtained organic phase was separated, washed with water, a saturated aqueous sodium hydrogencarbonate solution and a saturated aqueous NaCl solution and dried over anhydrous sodium sulfate. After filtration, the solvent was evaporated under reduced pressure and the residue was purified by silica gel chromatography (ethyl acetate) to obtain the title compound (4.23 g, yield: quantitative).

Provenance & Evidence