144120-53-6

144120-52-5

144120-53-6

Procedure for the synthesis of Nα-Fmoc-L-aspartic acid α-allyl ester: Nα-Fmoc-L-aspartic acid (OH) allyl ester (0.77 g; 1.94 mmol) was dissolved in a mixture of dichloromethane (DCM, 4 ml) and trifluoroacetic acid (TFA, 2 ml), and the reaction was stirred for 1 h at room temperature. After completion of the reaction, the mixture was concentrated to dryness under reduced pressure. The resulting solid was dissolved in saturated aqueous sodium bicarbonate (NaHCO3) solution and washed with ether. Subsequently, it was acidified to pH 2 with 5% hydrochloric acid (HCl) to produce a white precipitate. It was extracted twice with ethyl acetate (EE) and the organic phases were combined. The organic phase was washed with acidified water (HCl, pH 1), dried over anhydrous sodium sulfate (Na2SO4), and evaporated under reduced pressure to afford the target product Nα-Fmoc-L-aspartic acid α-allyl ester (87% yield). The product was structurally confirmed by 1H NMR (250 MHz, DMSO-d6) and 13C NMR (75 MHz, CDCl3), and the purity was verified by ESI-MS (m + Na: 418.1) and HPLC (Rt: 22.0 min, gradient 10-100%).