1,2,3-Triazolium-Based Peptoid Oligomers

Abstract

The cis-directing effect of the 1,2,3-triazolium-type side chain was studied on dimeric peptoid models with various patterns: αα, αβ, βα and ββ. Low influences of the sequence and of the solvent were observed, the cis conformation of the amide carrying the triazolium ranging from 83 to 94% in proportion. The synthesis of peptoid homooligomers with four or eight pendant 1,2,3-triazolium side chains is described. α-, β- and α,β-peptoids carrying propargyl groups were subjected to CuAAC reaction using alkyl azides, and the resulting triazoles were quaternized providing well-defined multitriazolium platforms. The influence of the counteranion (PF, BF or I) on the conformation was also studied.

NCα‐gem‐dimethylated peptoid side chains: A novel approach for structural control and peptide sequence mimetics

“…The cis/trans ratio of the terminal acetamide was determined for all the trimer peptoids 4 ‐ 9 by 1 H NMR integration of singlets corresponding to the acetyl CH 3 protons (Figure ). According to previous studies, the protons of trans peptoid acetamides are deshielded which results in a chemical shift of ˃2 ppm. On the contrary, it was observed that the protons of cis acetamides display a chemical shift of <2 ppm.…”

1,2,3‐Triazolium‐Based Cationic Amphipathic Peptoid Oligomers Mimicking Antimicrobial Helical Peptides

“…It is important to note that in the course of antimicrobial peptoid design, short oligomers were often poorly active except those incorporating the dehydroabietyl moiety or a long alkyl tail . The potency of peptoid 3 may be due to the structuring effect of the triazolium group . Preliminary CD studies on this series showed that peptoids 2 , 3 , and 9 present the characteristic CD signature of the PPI‐like helix of peptoids with two minima at 203 and 220 nm (Figure ) .…”

“…[21] The potency of peptoid 3 may be due to the structuring effect of the triazolium group. [14,16] Preliminary CD studies on this series showed that peptoids 2, 3,a nd 9 present the characteristicC Ds ignature of the PPI-like helix of peptoids with two minima at 203 and 220 nm (Figure 2). [8] The lower band intensity for triazolebased hexapeptoid 2 compared with the triazolium-based hexapeptoid 3 is indicative of helical structure stabilization by the triazoliums.…”

“…Using cyclohexylmethyl azide, the conversion of the alkynyl functions into triazolyls was achieved, yielding hexapeptoid 2 in 52 % yield. Conversion of the triazoles into triazoliums was tested using a well‐established protocol (Scheme ) . A complex mixture of compounds was obtained likely due to the presence of the primary amide and the unprotected terminal amine group.…”

“…Conversion of the triazoles into triazoliums was tested using aw ell-established protocol (Scheme 1). [16] Ac omplex mixture of compounds was obtained likely due to the presence of the primary amide and the unprotectedt erminal amine group. This result prompted us to develop an ew strategy consisting of forming the triazolium moiety directly on the resin after ap rerequisite protection of the N-terminal amine.…”