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DOI: 10.1055/s-0041-1737411
Synthesis of Peptide N-Acylpyrroles via Anodically Generated N,O-Acetals
This work was supported by the Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science (CE200100012) and the Westpac Foundation (Research Fellowship to L.R.M.).
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Abstract
An electrochemical approach to peptide C-terminal N-acylpyrroles is described from readily accessible C-terminal hydroxyproline-containing peptides, prepared via standard Fmoc solid-phase peptide synthesis (Fmoc-SPPS). Following electrochemical decarboxylation, the reactive hydroxyproline-derived N,O-acetal intermediate is aromatized under mild acidic conditions, which enable concomitant deprotection of amino acid side-chain protecting groups. The resulting peptide N-acylpyrrole is amenable to late-stage peptide modifications, including reduction with NaBH4 to deliver a valuable C-terminal peptide aldehyde motif.
Key words
decarboxylation - electrochemistry - anodic oxidation - aromatization - peptide N-acylpyrroles - late-stage modification - C-terminal modificationSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/s-0041-1737411.
- Supporting Information
Publication History
Received: 21 January 2022
Accepted after revision: 23 February 2022
Article published online:
09 May 2022
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An earlier term, amidity, has also been used to quantify amide bond strength; see:
For selected examples, see:
To simplify the peptide synthesis, side-chain unprotected Hyp was incorporated and capping steps were omitted to avoid the formation of O-acetylated Hyp. The incorporation of Fmoc-Hyp(Ac)-OH was avoided due to the tendency of this amino acid to aggregate; see:
For selected examples, see:
For selected examples, see: