(2R)-2-acetamidobutanedioic acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of acetic anhydride (85 μl, 0.90 mmol.) in acetonitrile (1 ml), there is added a solution of commercially available H-D-Asp(OBn)-OH (Senn Chemicals, CH-Dielsdorf) (200 mg, 0.90 mmol.) in a CH3CN.H2O/Et3N (3.5/1.0/0.4 ml) mixture. The reaction mixture is stirred for 18 hours at room temperature. The organic solvent is evaporated and the remaining aqueous phase is cooled down to 0° C., acidified with a 10% aqueous solution of citric acid till pH=3 and extracted with EtOAc (2×). The organic layers are pooled and dried over MgSO4, filtered and evaporated. The -benzyl ester of N-acetyl-D-aspartic acid obtained as a white crystalline solid (192 mg, 81%) is used in the next step with no further purification. (Rf=0.45 in 20/1 CH2Cl2/MeOH containing 2% of acetic acid, phosphomolybdinium compound and U.V. color development agent). The organic solvent is evaporated the remaining aqueous phase is cooled down to 0° C. extracted with EtOAc (2×) dried over MgSO4 filtered evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of acetic anhydride (85 μ1, 0.90 mmol.) in acetonitrile (1 ml), there is added a solution of commercially available H-D-Asp(OBn)-OH (Senn Chemicals, CH-Dielsdorf) (200 mg, 0.90 mmol.) in a CH3CN.H2O/Et3N (3.5/1.0/0.4 ml) mixture. The reaction mixture is stirred for 18 hours at room temperature. The organic solvent is evaporated and the remaining aqueous phase is cooled down to 0° C., acidified with a 10% aqueous solution of citric acid till pH=3 and extracted with EtOAc (2×). The organic layers are pooled and dried over MgSO4, filtered and evaporated. The -benzyl ester of N-acetyl-D-aspartic acid obtained as a white cristalline solid (192 mg, 81%) is used in the next step with no further purification. (Rf=0.45 in 20/1 CH2Cl2/MeOH containing 2% of acetic acid, phosphomolybdinium compound and U.V. color development agent). The organic solvent is evaporated the remaining aqueous phase is cooled down to 0° C. extracted with EtOAc (2×) dried over MgSO4 filtered evaporated