Synthesis of dendritic polyamides via a convergent growth approach

The synthesis of dendritic polyamides by the convergent growth approach is described. The synthesis involves an A₂B monomer, N-(tert-butoxycarbonyl)iminodipropionic acid, containing two free carboxylic acid groups and a protected amine. The polycondensation reaction is carried out using classical peptide chemistry with sequential coupling-deprotection steps to afford polyamides with molecular weights up to 5000. As their size increases, the dendritic polyamide find their growth restricted by steric problems. The final step of growth is the condensation of the dendrimers with a trifunctional acid chloride core to give the final globular polyamides. The macromolecules were characterised by a variety of chromatographic and spectroscopic techniques, and were found to have precisely defined structures.