Issue 43, 2020

Insight into the synthesis of N-methylated polypeptides

Abstract

The ring-opening polymerization (ROP) of N-carboxy anhydrides (NCAs) is mostly divided into two classes: NCAs of α-substituted amino acids and N-methylated NCAs of α-unsubstituted glycine derivatives (NNCAs). The use of both monomer types offers different mechanistic features and results in a multitude of functional materials. To combine these properties, the synthesis and ROP of α-substituted and N-methylated NCAs (αNNCAs) of several amino acids were investigated. The current study provides insight into the influence of polymerization conditions and the limitations caused by the enhanced steric demand of the amino acid NCA monomers and their N-methylated derivatives. Namely, the effects of solvent polarity (DMF and DCM) and steric demand of the initiator by using neopentyl amine (NPA) and n-butyl amine (nBu) were studied. Analysis by HFIP-GPC and MALDI-ToF MS reveals that the polymerization and the resulting polymers are tremendously affected by the steric demand of both the initiators and the monomers, while electronic effects seem to have only minor influences. The experimental results are further compared with computational studies, based on coupled cluster (CC) calculations, which underline that electronic effects are of lower importance than steric constraints for the ROP of αNNCAs. Moreover, poly(N-methyl-L-methionine) forms helical secondary structures in solution. Therefore, this work combines mechanistic studies of the ROP of αNNCAs with initial studies on the solution properties of these polypeptides.

Graphical abstract: Insight into the synthesis of N-methylated polypeptides

Supplementary files

Article information

Article type
Paper
Submitted
23 Jul 2020
Accepted
05 Oct 2020
First published
06 Oct 2020

Polym. Chem., 2020,11, 6919-6927

Insight into the synthesis of N-methylated polypeptides

C. Muhl, L. Zengerling, J. Groß, P. Eckhardt, T. Opatz, P. Besenius and M. Barz, Polym. Chem., 2020, 11, 6919 DOI: 10.1039/D0PY01055C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements