N-carboxy-anhydrides derived from threo- and erythro-β-hydroxyaspartic acids and poly-β-methyl hydrogen threo-β-methoxy-DL-aspartate

Abstract

The N-carboxy-anhydrides derived from either threo- or erythro-β-hydroxy-DL-Aspartic ACID In which the hydroxy-group is protected by an acetyl group and the β-carboxy-group by a benzyl or methyl ester do not undergo polymerisation in solution by basic catalysts or in bulk. This is due to an O→N-acetyl shift. Polymerisation does take place after methylation of the hydroxy-group.