Bioconjugation through Mesitylene Thiol Alkylation

Abstract

The design and generation of complex multifunctional macromolecular structures by bioconjugation is a hot topic due to increasing interest in conjugates with therapeutic applications. In this regard, the development of efficient, selective, and safe conjugation methods is a major objective. In this report, we describe the use of the bis(bromomethyl)benzene scaffold as a linker for bioconjugation with special emphasis on antibody conjugation. We first performed the monothioalkylation of 1,3,5-tris(bromomethyl)benzene, which rendered the reactive dibromotrimethylbenzyl derivatives to be used in thiol bis-alkylation. Next, we introduced into the linker either a bis(Cys)-containing peptide or anti-CD4 and -CD13 monoclonal antibodies, previously subjected to partial reduction of disulfide bonds. Mass spectrometry, UV-vis spectra, and SDS-PAGE experiments revealed that this bis-alkylating agent for bioconjugation preserved both antibody integrity and antibody-antigen binding affinity, as assessed by flow cytometry. Taken together, our results show that the mesitylene scaffold is a suitable linker for thiol-based bioconjugation reactions. This linker could be applicable in the near future for the preparation of antibody drug conjugates.

Innovative Bioconjugation Technology for Antibody–Drug Conjugates: Proof of Concept in a CD30-Positive Lymphoma Mouse Model

“…Convinced by the great potential of ADCs, we, among other teams, explored new linker technologies to produce improved ADC products especially with innovative rebridging bioconjugation heads. Pioneer work used the same mechanism of Michael addition, either using a maleimide motif − or replacing it with other scaffolds such as bis-sulfone, 3-arylpropiolonitrile, or carbonylacrylic reagents. , However, it has been hypothesized − that removing the maleimide motif and changing the nature of the bioconjugation chemical reaction would improve the overall properties of the immunoconjugates.…”

Macrocyclization strategies for cyclic peptides and peptidomimetics

“… 106 Another approach reacted tribromomethylenebenzene ( 30 ) monovalently with a wide variety of groups, including biotin, cholesterol, arachidonic acid and carboxyfluorescein, before cyclizing the unprotected peptide with the functionalized scaffold. 107 The same approach has been used for the bioconjugation of proteins and antibodies, 108 though a major drawback of bromomethylenearyl scaffolds is their limited solubility in aqueous solutions. Therefore, Smeenk et al designed a bromomethylene scaffold ( 29 ) that combines improved solubility with the option for functionalization.…”

A concise review on the stereoselective synthesis of chiral α-bisamides using stereoselective Ugi-type reaction

“…The Ugi reaction involves a one-pot condensation of four components, an aldehyde or a ketone, an isocyanide, an amine, and a carboxylic acid to furnish α-bisamides. 1,2 In addition to three new bonds (two C-N bonds and one C-C bond) a new stereogenic center may be generated in this reaction by using a prochiral ketone / aldehyde having enantiotopic / diastereotopic faces. As one stereocenter can be generated, the search for its stereoselective version has become a much-desired goal among synthetic organic chemists.…”