Aromatic oligoamides with a rare ortho-connectivity: synthesis and study of ortho-arylopeptoids

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  • T. Hjelmgaard
  • John Nielsen
Even though aromatic oligoamides composed of aromatic amino acids in a "one-way sequence" attract ever increasing research interest, backbones connected through ortho-linked aromatics remain rare. Herein, we present the first synthesis and study of N-alkylated ortho-aminomethyl- benzamides termed "ortho-arylopeptoids". The ortho-arylopeptoids may, with a few exceptions, be synthesized either in solution or on solid-phase using unique and highly efficient submonomer methods with similar levels of high generality and efficiency to those previously demonstrated for meta- and para-arylopeptoids. NMR studies indicated a more restricted rotation about the amide bonds in ortho-arylopeptoids, presumably due to a more congested backbone structure resulting from the ortho-connectivity pattern. Intriguingly, tert-butyl and phenyl side chains offer complete control over the amide conformations; whereas arylopeptoid residues with tert-butyl side chains adopt a 100 % cis amide conformation, the opposite 100 % trans amide conformation was observed in arylopeptoids with phenyl side chains. The tert-butyl moiety can furthermore serve as a protecting group during synthesis, which can later be removed to allow the amide to adopt a 100 % trans conformation instead.
Original languageEnglish
JournalEuropean Journal of Organic Chemistry
Volume2013
Issue number17
Pages (from-to)3574-3589
Number of pages16
ISSN1434-193X
DOIs
Publication statusPublished - 1 Jun 2013

ID: 49040403