Macromolecular Rapid Communications, Vol.29, No.21, 1721-1725, 2008
An Improved Rapid Synthesis of Oligo (p-benzamide) Block Copolymers
We describe a new synthesis that allows the preparation of oligo(p-benzamide)s up to the heptamer on solid support without the need of semi-temporary amide N-protective groups. With increase in length, the solubility of oligo(p-benzamide)s reduces dramatically. Even the tetra (p-benzamide) is not soluble in common organic solvents. Therefore, solution syntheses of oligomers beyond the tetramer are not feasible. As will be shown in this paper, solid supported synthesis allows the preparation of even longer oligomers (up to the heptamer) in good yields. The high dilution on the solid support is most likely responsible for their pseudo-solution-like reactivity and the prevention of aggregation. This procedure is a significant improvement of previous syntheses and an important tool for the rapid exploration of supramolecular rod-coil copolymers based on oligoaramides.
Keywords:aggregates;aramide;block copolymers;rod-coil block copolymers;solid supported synthesis;supramolecular polymers;TEM