Phthalimide → 1H-Isoindole-1,3(2H)-dione, 4-amino-

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Reaction Steps

A mixture of 4 g (21 mmol) of the preceeding diamine, 4.6 g (21 mmol) of di-tert-butyl dicarbonate, and 100 mL of dry CH2Cl2 was stirred for 12 hours at room temperature. Solvent and volatile by-products were removed by evaporation under reduced pressure, leaving 6 g (100% yield) of 6-(tert-butyloxycarbonylamino)-1-diethylamino-2-hydroxyhexane as an oil which was not further purified. It was dissolved in 100 mL of dry tetrahydrofuran (THF) along with 3.27 g (22 mmol) of phthalimide, 5.77 g (22 mmol) of triphenylphosphine, and 3.83 g (22 mmol) of diethyl azodicarboxylate (DEAD). The solution was stirred at room temperature for 12 hours at which point, to complete the reaction, an additional 1.64 g (11 mmol) of phthalimide and 1.92 g (11 mmol) of DEAD were added and stirring continued for 1 hour. Solvent was removed and the residual oil partitioned between ether and 1% hydrochloric acid. The aqueous phase was separated, made basic with NaOH solution, and extracted with ether. The ether extract was dried over anhydrous MgSO4, filtered and evaporated. A pale yellow oil resulted which was dried under high vacuum to afford 9.2 g of the protected amino-phthalimide as a pale yellow oil.

Provenance & Evidence