Cyclic Peptide–Polymer Complexes and Their Self‐Assembly

Abstract

The efficient synthesis of novel chiral cyclic peptides cyclo[NHCHX-CH=CHCH(2)CO(NHCH(2)CH=CHCH(2)CO)(2)] designed to develop hydrogen-bonding interactions with suitable polymers is described. Complexation of a carboxylic acid derivatized cyclic peptide 2 (X = CH(2)OCOCH(2)CH(2)CO(2)H) capable of self-assembling as "endless" tubes, with poly(vinyl alcohol) (PVA) led to a vast weak-interaction network, in which the cyclopeptide developed extensive hydrogen-bonding interactions with the hydroxyl groups of PVA through not only the carboxylic acid, but also its ester carbonyl and amide groups. In aqueous solution, the peptide/PVA complexes self-assemble into long-grain ricelike aggregates compatible with the stacking of cyclic peptides through intercycle hydrogen bonds. Upon casting on silicon wafer, the anisotropic aggregates can coalesce to form filaments tens of micrometers long. The study demonstrates that complexing functionalized cyclic peptides with polymers through hydrogen bonding is a useful approach for using polymers to mediate the self-assembly and self-organization of cyclic peptides.

Exploring the Backbone of Enkephalins To Adjust Their Pharmacological Profile for the δ-Opioid Receptor

“…The ester was reduced to the aldehyde 10 with dibutyl aluminum hydride; 10 was directly used without additional purification in the subsequent Wittig reaction to yield the alkene 11. Both alkenes 11 and 12 were coupled in a metathesis reaction to give fully protected Tyr//Gly, 13 (37). Hydrolysis of the benzyl ester of 13 produced 14 in a ready-to-use form as a normal protected amino acid in solid-phase peptide synthesis (SPPS).…”

Polyelectrolytes with Tunable Charge Based on Polydehydroalanine: Synthesis and Solution Properties

“…One clear advantage of polymers derived from t BAMA is that the resulting materials can be selectively transformed into weak polyelectrolytes, either polycations (polyamines) or polyanions (substituted poly(acrylic acid); Scheme ) . Furthermore, consecutive deprotection of both functional groups, if successful, should lead to the formation of potentially zwitterionic polymers with a high charge density and the location of opposite charges in close proximity along the polymeric backbone …”

Gold-catalyzed oxycyclization of allenic carbamates: expeditious synthesis of 1,3-oxazin-2-ones

“…Thus, alkynylcarbamates 1a – g were prepared through reductive amination of the appropriate aldehyde with propargylamine, followed by Boc 2 O treatment of the corresponding N-substituted prop-2-yn-1-amine. Alkynylcarbamate 1h was prepared from Garner’s aldehyde following a literature report [56–57]. Alkynylcarbamate 1i was readily accessed from ( S )-prolinol by using a modified known procedure [58].…”