Pht-Gly-OtBu

5292-43-3

1074-82-4

6297-93-4

A 250 mL three-necked flask was equipped with a thermocouple, nitrogen inlet tube and magnetic stirrer and tert-butyl bromoacetate (10 g, 51 mmol) was added. Subsequently, acetone (100 mL) was added as a solvent and tetrabutylammonium bromide (0.8 g, 2.5 mmol) was added as a phase transfer catalyst. The potassium salt of phthalimide was added all at once and the reaction system was heated to 45 °C and maintained for 15 hours. Upon completion of the reaction, the mixture was cooled to 21 °C and concentrated by rotary evaporator to remove acetone. Ethyl acetate (100 mL) and water (30 mL) were added to the concentrate and stirred at 21 °C for 20 min to achieve phase separation. The organic layer was separated and washed sequentially with saturated sodium carbonate solution (3 x 30 mL) and brine. The organic phase was concentrated to remove volatile solvents. The crude product was suspended in ethanol (30 mL) and water (30 mL) was added slowly for 30 minutes. The suspension was stirred overnight at 21 °C, followed by collection of the solid product by filtration and washing with water to give the final tert-butyl 2-(1,3-dioxoisoindolin-2-yl)acetate in 78.4% isolated yield and 99.29% HPLC purity.