Hydrochloric Acid → 3-(2-Methoxycarbonylamino-3-methyl-butyryl)-1-phenyl-imidazolidine-4-carboxylic acid methyl ester

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Reaction Steps

3-(2-Methoxycarbonylamino-3-methyl-butyryl)-imidazolidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester (0.20 g, 0.515 mmol) was dissolved in dichloromethane (1.0 mL) and HCl (4M dioxane, 1 mL) was added. The resultant suspension was stirred at room temperature for 60 minutes, after which all volatiles were removed in vacuo. The crude material was combined with phenyl boronic acid (188 mg, 1.545 mmol) and DCM (15 mL) was added. Triethylamine (1.2 mL, 8.89 mmol) was added, followed by copper(II) acetate and molecular sieves 4 Å. The reaction was stirred at room temperature. After 24 hrs, the reaction was quenched with aqueous ammonium hydroxide solution (10%) and the organic layer was isolated. The organic layer was washed with aqueous HCl solution (0.5 M), brine, and was dried over sodium sulfate. Filtration and evaporation gave crude material. Purification via flash chromatography on silica gel (eluent: EtOAc/hexanes) yielded the desired product 3-(2-Methoxycarbonylamino-3-methyl-butyryl)-1-phenyl-imidazolidine-4-carboxylic acid methyl ester (51.0 mg, 0.14 mmol): LCMS-ESI+: calc'd for C18H25N3O5: 363.4 (M+). Found: 364.4 (M+H+).

Provenance & Evidence