Hydrochloric Acid → (1-{3-Acetyl-5-[2-(4-bromo-phenyl)-2-oxo-ethylcarbamoyl]-imidazolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester

Participants

Reaction Steps

1-Acetyl-3-(2-methoxycarbonylamino-3-methyl-butyryl)-imidazolidine-4-carboxylic acid methyl ester (273 mg, 0.829 mmol) was dissolved in THF (1.8 mL) and MeOH (1.2 mL). An aqueous solution of LiOH (34.8 mg, 0.829 mmol) was added and stirring at room temperature was continued. After the hydrolysis was complete, the reaction was neutralized with aqueous HCl (0.83 mL, 1M). The organic solvents were removed in vacuo and the aqueous suspension was frozen and lyophilized. The crude material was used in the next step without further purification. The crude material was dissolved in DMF (3 mL) and HATU (315 mg, 0.829 mmol) and DIEA (106 mg, 0.829 mmol) were added. The reaction was stirred at room temperature for five minutes, after which the amino-(4′bromo) acetophenone hydrochloride salt (207 mg, 0.829 mmol) was added. Stirring at room temperature was continued. After 120 minutes, all volatiles were removed in vacuo and the crude material was dissolved in DCM. The organic layer was washed with aqueous HCl (0.5 M), aqueous lithium chloride solution (5%), brine and was dried over sodium sulfate. Filtration and evaporation of solvents yielded crude product which was purified via silica gel chromatography (eluent EtOAc/hexanes) to yield the product (1-{3-Acetyl-5-[2-(4-bromo-phenyl)-2-oxo-ethylcarbamoyl]-imidazolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (203 mg, 0.397 mmol): LCMS-ESI+: calc'd for C21H27BrN4O6: 511.4 (M+). Found: 511.3/513.2 (M+H+).

Provenance & Evidence