Configuration-Dependent Medium-Sized Ring Formation: Chiral Molecular Framework with Three-Dimensional Architecture

This report describes a configuration-dependent [6 + 8 + 5] fused ring formation via a tandem cyclic N-acyliminium nucleophilic addition reaction. Cyclization of the acyclic precursor prepared on a solid phase using l-Ser and a racemic mixture of Fmoc-trans-2-aminocyclohexanecarboxylic acid predominantly yielded the cyclic diastereomer with the (1R,2R)-2-aminocyclohexane moiety rather than the tricyclic diastereomer from the (1S,2S)-enantiomer. In contrast, the model compound prepared with d-Ser predominantly cyclized with the (1S,2S)-2-aminocyclohexanecarboxylic acid substrate. The outcome of the cyclization was not influenced by the type of resin, the spacer, or the N-substituent. The analogous synthesis of the [6 + 7 + 5] fused ring system yielded inseparable diastereomers in a 1:0.6 ratio.Fil: Cankarova, Nadezda. Palacky University; República ChecaFil: la Venia, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Krajcovicova, Sona. Palacky University; República ChecaFil: Krchnak, Viktor. Palacky University; República Chec

Ideas Behind the Tryptophan-Mediated Petasis Reaction (TMPR) Concept for Peptide Stapling.

This Concept short review offers an insightful analysis of pivotal research papers and explores the key synthetic ideas behind the intersection of two realms in peptide chemistry: using tryptophan and Petasis multicomponent reactions for macrocyclisation and labelling of peptides. The recently published tryptophan-mediated Petasis reaction (TMPR) concept represents a critical junction between these two worlds, highlighting how combining such methodologies leads to more effective and versatile synthetic strategies, setting a potentially new direction for future research in the field of peptide-drug conjugates

Tryptophan in Multicomponent Petasis Reactions for Peptide Stapling and Late‐Stage Functionalisation

Funder: Nadace Experientia (Experientia Foundation); doi: http://dx.doi.org/10.13039/100013994AbstractPeptide stapling is a robust strategy for generating enzymatically stable, macrocyclic peptides. The incorporation of biologically relevant tags (such as cell‐penetrating motifs or fluorescent dyes) into peptides, while preserving their binding interactions and enhancing their stability, is highly sought after. Despite the unique opportunities offered by tryptophan‘s indole scaffold for targeted functionalisation, its utilisation in peptide stapling has been limited as compared to other amino acids. Herein, we present an approach for peptide stapling using the tryptophan‐mediated Petasis reaction. This method enables the synthesis of both stapled and labelled peptides and is applicable to both solution and solid‐phase synthesis. Importantly, the use of the Petasis reaction in combination with tryptophan facilitates the formation of stapled peptides in a straightforward, multicomponent fashion, while circumventing the formation of undesired by‐products. Furthermore, this approach allows for efficient and diverse late‐stage peptide modifications, thereby enabling rapid production of numerous conjugates for biological and medicinal applications.</jats:p

Tryptophan in Multicomponent Petasis Reactions for Peptide Stapling and Late-Stage Functionalisation.

Funder: Nadace Experientia (Experientia Foundation); doi: http://dx.doi.org/10.13039/100013994Peptide stapling is a robust strategy for generating enzymatically stable, macrocyclic peptides. The incorporation of biologically relevant tags (such as cell-penetrating motifs or fluorescent dyes) into peptides, while preserving their binding interactions and enhancing their stability, is highly sought after. Despite the unique opportunities offered by tryptophan's indole scaffold for targeted functionalisation, its utilisation in peptide stapling has been limited as compared to other amino acids. Herein, we present an approach for peptide stapling using the tryptophan-mediated Petasis reaction. This method enables the synthesis of both stapled and labelled peptides and is applicable to both solution and solid-phase synthesis. Importantly, the use of the Petasis reaction in combination with tryptophan facilitates the formation of stapled peptides in a straightforward, multicomponent fashion, while circumventing the formation of undesired by-products. Furthermore, this approach allows for efficient and diverse late-stage peptide modifications, thereby enabling rapid production of numerous conjugates for biological and medicinal applications

[68Ga]Ga-DFO-c(RGDyK): Synthesis and Evaluation of Its Potential for Tumor Imaging in Mice

Angiogenesis has a pivotal role in tumor growth and the metastatic process. Molecular imaging was shown to be useful for imaging of tumor-induced angiogenesis. A great variety of radiolabeled peptides have been developed to target αvβ3 integrin, a target structure involved in the tumor-induced angiogenic process. The presented study aimed to synthesize deferoxamine (DFO)-based c(RGD) peptide conjugate for radiolabeling with gallium-68 and perform its basic preclinical characterization including testing of its tumor-imaging potential. DFO-c(RGDyK) was labeled with gallium-68 with high radiochemical purity. In vitro characterization including stability, partition coefficient, protein binding determination, tumor cell uptake assays, and ex vivo biodistribution as well as PET/CT imaging was performed. [68Ga]Ga-DFO-c(RGDyK) showed hydrophilic properties, high stability in PBS and human serum, and specific uptake in U-87 MG and M21 tumor cell lines in vitro and in vivo. We have shown here that [68Ga]Ga-DFO-c(RGDyK) can be used for αvβ3 integrin targeting, allowing imaging of tumor-induced angiogenesis by positron emission tomography

Site-selective peptide functionalisation mediated via vinyl-triazine linchpins †

Herein we introduce 3-vinyl-1,2,4-triazines derivatives as dual-reactive linkers that exhibit selectivity towards cysteine and specific strained alkynes, enabling conjugate addition and inverse electron-demand Diels–Alder (IEDDA) reactions. This approach facilitates site-selective bioconjugation of biologically relevant peptides, followed by rapid and highly selective reactions with bicyclononyne (BCN) reagents

Disulfide re-bridging reagents for single-payload antibody-drug conjugates.

Numerous antibody-drug conjugate (ADC) linker technologies exist for the synthesis of ADCs with drug-to-antibody ratios (DARs) being an even integer (typically 2, 4 or 8). However, ADCs with odd-integer DARs are significantly harder to synthesise. Here, we report the synthesis of ADCs loaded with a single warhead, using TetraDVP linkers which simultaneously re-bridge all four interchain disulfides of an IgG1 antibody