Triethylamine → 3-[(2-Tert-butoxycarbonylamino-ethyl)-ethoxycarbonyl-amino]-2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-propionic acid methyl ester

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Reaction Conditions

Reaction Steps

To a solution of 18.80 g (47.54 mmol) of 3-(2-tert-butoxycarbonylamino-ethylamino)-2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-propionic acid methyl ester dissolved in 156 mL of anhydrous dichloromethane was added 8.02 mL (57.05 mmol) of triethylamine. The resulting mixture was cooled at 0° C. and 5.00 mL (52.29 mmol) of ethyl chloroformate dissolved in 30 mL of anhydrous dichloromethane was added. The resulting mixture was stirred at room temperature for 12 h. Saturated aqueous solution of ammonium chloride was added and the mixture extracted with dichloromethane. The extracts were washed with a saturated aqueous solution of sodium chloride, sodium carbonate, dried over sodium sulfate and evaporated to dryness. The residue was chromatographed on silica gel eluting with a mixture of dichloromethane/methanol in the proportions 99/1 led to afford 20.00 g (90%) of the desired compound as an oil.

Provenance & Evidence