Aspartic anhydrides

Aspartic acid Fumaric acid 2-Amino-1,4-butanediol, 3-aminotetrahydrofuran, amino-2-pyrrolidone, aspartic anhydride Werpy and Petersen 2004... 

C2BH4,N204 137431-06-2) see Saquinavir L-aspartic anhydride hydrochloride (QHsCINOj 34029-31-7) see Aspartame atropine... 

Fu J, Krauland E, Har-el Y, Hanes J. Biodegradable cationic poly(aspartic anhydride-co-ethylene glycol) Synthesis, characterization, and self-assembly with plasmid DNA, submitted to Macromolecules. 

Z-D-aspartic anhydride is synthesized from Z-D-aspartic acid in the same way as that for Z-L-aspartic anhydride. 

To a solution of L-phenylalanine methyl ester (8 mmol, 1.434 g) in dimethyl sulfoxide (60 mL) is added Z-L-aspartic anhydride (8 mmol, 1.994 g) under stirring. The reaction continues at 20°C for S h. The reaction mixture is then poured into distilled water (1.2 L). Acidification with 1M hydrochloride acid (7-8 drops) gives a crude product as white precipitate. This is separated by filtration, dried in a vacuum and re-crystallized from ethyl acetate. Optical activity ([a]o) in methanol +10.0. 

Z-D-Asp(D-Phe-OMe) -OH is synthesized from Z-D-aspartic anhydride and D-phenylalanine methyl ester in the same way as for Z-L-Asp(L-Phe-OMe)-OH. Optical activity ([aJo) in methanol —10.0. 

Z-L-aspartic anhydride (2 mmol) is dissolved in acetonitrile (20 mL). To the solution is added L-phenylalanine methyl ester (2 mmol) under stirring. The reaction continues at 20°C for 2 h. After the reaction, the solution is diluted 10 times with acetonitrile. The composition of the mixture is analyzed by RP HPLC using an ODS column and UV detection at 210 nm. Mobile phase 50% (v/v) acetonitril in 10 mM phosphate buffer, pH 4.15 flow rate 0.5 mL min ... 

This is the regioselectivity observed in the addition of amines to phthaloyl aspartic anhydride, sterically controlled King, F. E. Kidd, D. A. A. J. Chem. Soc. 1951, 243. 

A Japanese patent describes the preparation of iV-formyl aspartic anhydride by direct reaction of L-aspartic acid with formic acid in the presence of acetic anhydride and an optional catalyst. Reaction is complete after 12 h of sonolysis at 45 °C and gives a 93 % isolated yield of the anhydride [198],... 

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