Two unprecedented N functionalizations of indoles with ynamides are described. By varying the electron-withdrawing group on the ynamide nitrogen atom, either Z-indolo-etheneamides or indolo-amidines can be selectively obtained under the same metal-free reaction conditions. The scope and synthetic potential of these reactions, as well as some mechanistic insights provided by DFT calculations, are reported.

Controlled protein functionalization holds great promise for a wide variety of applications.

Here we present the synthesis and evaluation of antibody-drug conjugates (ADcs), for which antibody and drug are non-covalently connected using complementary DnA linkers. these ADcs are composed of trastuzumab, an antibody targeting HER2 receptors overexpressed on breast cancer cells, and monomethyl auristatin e (MMAe) as a drug payload. in this new ADc format, trastuzumab conjugated to a 37-mer oligonucleotide (ON) was prepared and hybridized with its complementary ON modified at 5-end with MMAE (cON-MMAE) in order to obtain trastuzumab-DNA-MMAE. As an advantage, the con-MMAe was completely soluble in water, which decreases overall hydrophobicity of toxic payload, an important characteristic of ADcs. the stability in the human plasma of these non-engineered onbased linkers was investigated and showed a satisfactory half-life of 5.8 days for the trastuzumab-DnA format. finally, we investigated the in vitro cytotoxicity profile of both the DNA-linked ADC and the on-drug conjugates and compared them with classical covalently linked ADc. interestingly, we found increased cytotoxicity for MMAE compared to cON-MMAE and an EC50 in the nanomolar range for trastuzumab-DNA-MMAE on HER2-positive cells. Although this proved to be less potent than classically linked ADC with picomolar range EC50, the difference in cytotoxicity between naked payload and conjugated payload was significant when an ON linker was used. We also observed an interesting increase in cytotoxicity of trastuzumab-DNA-MMAE on HER2-negative cells. This was attributed to enhanced non-specific interaction triggered by the DNA strand as it could be confirmed using ligand tracer assay. Antibody-drug conjugates (ADCs) are promising therapeutic agents used mainly for cancer indications 1,2. There are currently seven ADCs on the market, including three ADCs approved by the US Food and Drug Administration (FDA) in 2019 3. Conjugation of highly potent cytotoxic drugs with antibodies recognizing the antigens overexpressed on cancer cells affords ADCs, which enable the delivery of the cytotoxic payload into the tumor cells in a controlled and selective manner. Following internalization and proteolytic cleavage, the drug induces tumor cell dysfunction and apoptosis. Classical approaches for the preparation of ADCs from native antibodies are based either on drug conjugation to exposed lysine residues or to cysteine residues generated by a reduction of interchain disulfide bonds 4. Alternatively, protein engineering and enzymatic approaches have been actively used for production of homogeneous ADCs 5,6. For more information about advancements in antibody, linker, and warhead technologies, we refer readers to several excellent reviews on these topics 7-9. We have recently reviewed antibody-oligonucleotide conjugates (AOCs) for applications as therapeutic and detection agents. Interestingly, AOCs have been used for targeted therapy as carriers of doxorubicin drug which was intercalated between the CG base pairs of the AOC's double-strand DNA (Fig. 1a) 10-12. The Gothelf ...

Two unprecedented N functionalizations of indoles with ynamides are described. By varying the electron‐withdrawing group on the ynamide nitrogen atom, either Z‐indolo‐etheneamides or indolo‐amidines can be selectively obtained under the same metal‐free reaction conditions. The scope and synthetic potential of these reactions, as well as some mechanistic insights provided by DFT calculations, are reported.

Transition-Metal-Free Tunable Chemoselective N Functionalization of Indoles with Ynamides. -Two new reaction pathways of ynamides with heterocycles containing a N-unsubstituted pyrrole unit are developed using NaOtBu as the base. Either Z-indolo-etheneamides or indolo-amidines (XI) can be selectively obtained under the same reaction conditions. -(HENTZ, A.; RETAILLEAU, P.; GANDON, V.; CARIOU, K.; DODD*, R. H.; Angew. Chem., Int. Ed. 53 (2014) 32, 8333-8337, http://dx.doi.org/10.1002/anie.201402767 ; Inst. Chim. Subst. Nat., CNRS, F-91198 Gif-sur-Yvette, Fr.; Eng.) -Mais 05-134