Supramolecular PEG−co-Oligo(p-benzamide)s Prepared on a Peptide Synthesizer

Abstract

An automated synthesis protocol has been developed for the preparation of oligo(p-benzamide)s on solid support using a commercial peptide synthesizer employing a variation of standard Fmoc chemistry. Bis(trichloromethyl carbonate) in NMP was used to activate the aromatic carboxylic acids for acylation of secondary aromatic amines on solid support. N-Protected hepta(p-benzamide) was automatically prepared on solid support and manually converted to a solid supported block co-oligomer by attaching a poly(ethylene glycol) chain. Cleavage from the support could be achieved with minimal loss of the p-methoxybenzyl N-protective group. While the N-protected block co-oligomer was molecularly dissolved in nonpolar organic solvents, the N-deprotected block co-oligomer adopted a rod-coil conformation and showed strong aggregation as evidenced by gel permeation chromatography and transmission electron microscopy. Rigid rodlike aggregates could be observed in chloroform, toluene, as well as water.

Tuning the solubility of hepta(p-benzamide)s via the monomer sequence

“…8 They have also been extensively used in the shape of conjugated electro-and photoactive materials. 9,10 We recently reported several synthetic routes to rigid rod-like oligo(p-benzamide)s employing modified peptide coupling protocols on commercially available peptide synthesizers 11,12 and using solution chemistry. 13 Oligo(p-benzamide)s (OPBA) are particularly rigid aromatic amides which suffer from poor solubility due to their linearly aligned hydrogen bond donors and acceptors.…”

Polymeric Janus Particles

“…[43,44] Most morphologies of diblock copolymers that have been investigated are centrosymmetric; less-symmetric rod-like aggregates can however be formed by special copolymer architectures, such as polymers containing dendritic segments [45] or rod-coil polymers. [46,47] The formation of various kinds of microphase-separated structures, such as spheres, cylinders, lamellae, or gyroids, can be controlled by the block ratios and by adjusting the miscibility of the respective segments of the block copolymers. [48] For ABC-terblock copolymers, a great variety of morphologies can be found by variation of the block ratios.…”

Der Natur abgeschaut: β‐Faltblatt‐Oligopeptide und Analoga organisieren Blockcopolymere

“…[43] Unter Verwendung von Amidschutzgruppen, die eine Aggregation verhinderten, konnte die Synthese auch an der Festphase durchgeführt werden. [44,45] OPBA-7-mere wurden vollautomatisch an einem Festphasenträger synthetisiert und mit PEG konjugiert. TEM-Aufnahmen zeigten kettensteife Aggregate mit Breiten von ca.…”

“…Die in TEM-Aufnahmen beobachteten Aggregate glichen denjenigen, die definiert in Lösung oder an einem Trägerharz hergestellt wurden. [43,45] Wie schon zuvor beobachtet, entsprach die Breite der Aggregate den molekularen Abmessungen der Oligomere. Der leichte Zugang zu größeren Mengen an OPBA-Copolymeren wird es zukünftig ermöglichen, Materialeigenschaften genauer zu untersuchen.…”

“…In beiden Aufnahmen werden stäbchenartige Micellen beobachtet. [45] Schema 1. Synthese von OPBA-Copolymeren im größeren Maßstab über eine automatisierte Syntheseroute.…”