Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• Marine Le Stum Eugenie Romero Gary A. Molander Université Paris-Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SCBM, 91191 Gif-Sur-Yvette, France 10.3762/bjoc.21.49 Abstract Antibody–drug conjugates (ADCs) represent a promising class of targeted therapeutics

• functionalized antibodies. Perspective In this perspective, how light-driven chemistry can enhance the development of innovative methods for accessing antibody–drug conjugates (ADCs) will be outlined. A brief introduction to photoredox chemistry as it relates to bioconjugation in proteins is followed by a

• facilitate various modifications, including labeling, crosslinking, and the creation of protein–drug conjugates. The incorporation of photoredox strategies has facilitated the synthesis of complex protein architectures, enabling precise control over conjugation sites and degrees of modification. The number

Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• University, Universitätsstraße 25, 33615 Bielefeld, Germany 10.3762/bjoc.21.40 Abstract Drug conjugates using toxic payloads are a promising approach for selectively combating cancer while sparing healthy tissue. The lack of highly cytotoxic and at the same time selective therapeutics against cancer is an

• derivatives lack a covalent attachment handle. By making use of drug conjugates, toxic payloads such as cryptophycins can be selectively delivered to the target site. We present the synthesis of two conjugable cryptophycins with amino groups in unit B, representing potential payloads for drug conjugates

• particularly effective against multidrug-resistant cancers. Keywords: cancer treatment; cryptophycins; drug conjugates; payload; targeted delivery; Introduction Cryptophycins emerged as highly potent cytotoxins for the use in targeted cancer therapy [1]. Originally discovered over three decades ago by

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• therapeutics, particularly in antibody–drug conjugates (ADCs). Cysteine (Cys) holds a special place in this context due to the distinctive nucleophilicity of its thiol side chain. The cysteine thiol group offers a reactive handle for site-selective modifications, allowing for the attachment of various

Copper-catalyzed monoselective C–H amination of ferrocenes with alkylamines

• Zhen-Sheng Jia,
• Qiang Yue,
• Ya Li,
• Xue-Tao Xu,
• Kun Zhang and
• Bing-Feng Shi

Beilstein J. Org. Chem. 2021, 17, 2488–2495, doi:10.3762/bjoc.17.165

• –drug conjugates (Scheme 4a). Three amines used to treat psychosis were subjected to couple with 1a and the desired conjugates were obtained in good yields (with haloperidol, 4p, 63%; with buspirone, 4q, 60%; with perospirone, 4r, 70%). This protocol was also amendable to gram-scale synthesis, giving 3a

• preparation of ferrocene–drug conjugates effectively. Mechanistic studies indicated that the C–H activation step was the rate-determining step. 3d-Transition-metal-catalyzed C–H functionalization to access functionalized ferrocenes. Scope of ferrocenes with morpholine. Scope of various amines with 1a

Total synthesis of ent-pavettamine

• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2021, 17, 1440–1446, doi:10.3762/bjoc.17.99

• metabolic regulators [5]. In addition to this, some PAs are currently being used as therapeutic drugs, being incorporated as drug conjugates, or are under investigation for other applications [6][7][8][9][10][11][12]. The elucidation of the structure of pavettamine revealed a new class of polyamines with a

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• biologically active molecules that already find practical use. It has been found that complexation improves the transportation of a drug and prolongs its effect, and a synergistic effect is observed in some cases [36]. The situation with covalent binding in fullerene–drug conjugates is different. C60 is an

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• cell lines [44]. Here, the incorporation of CF3 and CF3O groups as NMR reporters into the tumour-targeting drug conjugates enabled the direct investigation of the mechanism of the pro-drug metabolic cleavage and the pharmacophore release by real-time 19F NMR analysis. 19F NMR was also employed as a

Synthesis of a tubugi-1-toxin conjugate by a modulizable disulfide linker system with a neuropeptide Y analogue showing selectivity for hY1R-overexpressing tumor cells

• Rainer Kufka,
• Robert Rennert,
• Goran N. Kaluđerović,
• Lutz Weber,
• Wolfgang Richter and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2019, 15, 96–105, doi:10.3762/bjoc.15.11

• differential for tumor cells. Members of one prominent novel class of targeted anticancer drugs that has been developed over the last years are antibody–drug conjugates (ADCs) [9][10][11]. Due to their high antibody-mediated target specificity, ADCs are designed for selective treatments of tumor cells with

• market. However, many other ADC development projects are in clinical trials [12][13]. More recently, peptide–drug conjugates (PDCs) have been recommended as targeted therapeutics [14][15]. While sharing the ADCs’ therapeutic concept of targeted and highly selective drug addressing to the diseased cells

• been identified as fast and efficiently internalizing GPCR in those cells upon agonist binding [29][30]. The NPY Y1 receptor subtype for these reasons is a very promising molecular target to be addressed by selective peptide–drug conjugates (PDCs), notably for cancer treatment or diagnosis. However

Comparative cell biological study of in vitro antitumor and antimetastatic activity on melanoma cells of GnRH-III-containing conjugates modified with short-chain fatty acids

• Eszter Lajkó,
• Sarah Spring,
• Rózsa Hegedüs,
• Beáta Biri-Kovács,
• Sven Ingebrandt,
• Gábor Mező and
• László Kőhidai

Beilstein J. Org. Chem. 2018, 14, 2495–2509, doi:10.3762/bjoc.14.226

• -targeting by application of a GnRH analog as a carrier to deliver a covalently linked chemotherapeutic drug directly to the tumor cells. In this study our aim was (i) to analyze the effects of GnRH-drug conjugates on melanoma cell proliferation, adhesion and migration, (ii) to study the mechanisms of tumor

Drug targeting to decrease cardiotoxicity – determination of the cytotoxic effect of GnRH-based conjugates containing doxorubicin, daunorubicin and methotrexate on human cardiomyocytes and endothelial cells

• Livia Polgár,
• Eszter Lajkó,
• Pál Soós,
• Orsolya Láng,
• Marilena Manea,
• Béla Merkely,
• Gábor Mező and
• László Kőhidai

Beilstein J. Org. Chem. 2018, 14, 1583–1594, doi:10.3762/bjoc.14.136

• and his co-workers developed the first GnRH derivative–drug conjugates for targeted tumor therapy. One of these compounds Zoptarelin doxorubicin (developmental code names AEZS-108, AN-152) Glp-His-Trp-Ser-Tyr-D-Lys(Dox-O-glut)-Leu-Arg-Pro-Gly-NH2 (where glut is glutaric acid) [11] reached phase III

• for real-time monitoring of cells to distinguish short-term (0–2 hours) and long-term (0–72 hours) effects elicited by the drug or carrier–drug conjugates. The basic theory of impedimetry is that proliferation/viability of cells is well detectable by monitoring of the electric impedance (Z) in an AC

• and Figure 4b–g), whereas the data on short-term effects are presented in Supporting Information File 2. As mentioned above, the modified cytotoxic/cardiotoxic moiety of antitumor drugs in GnRH conjugates is focused in the present work. Results Synthesis of GnRH derivative–drug conjugates In this

Design and biological characterization of novel cell-penetrating peptides preferentially targeting cell nuclei and subnuclear regions

• Anja Gronewold,
• Mareike Horn and
• Ines Neundorf

Beilstein J. Org. Chem. 2018, 14, 1378–1388, doi:10.3762/bjoc.14.116

• excluded. However, initial drug delivery studies demonstrated the high versatility of these new peptides as efficient transport vectors targeting specifically nuclei and nucleoli. In future, they could be further explored as parts of newly created peptide–drug conjugates. Keywords: anticancer drugs; cell

• sC18 is also able to enter cells directly to some extent, which is among others depending on the cell lines used [20]. For a further exploration and development of peptide–drug conjugates, peptide sequences that specifically accumulate at intracellular target sites are needed. CPPs have been already

• shuttles. Having shown the great potency of CPP in anticancer drug research, these peptides could be used in future for the development of further innovative and highly effective peptide–drug conjugates. Experimental Materials All Nα-Fmoc protected amino acids (aa) were purchased from IRIS Biotech

Novel unit B cryptophycin analogues as payloads for targeted therapy

• Eduard Figueras,
• Adina Borbély,
• Mohamed Ismail,
• Marcel Frese and
• Norbert Sewald

Beilstein J. Org. Chem. 2018, 14, 1281–1286, doi:10.3762/bjoc.14.109

• analogues containing functional groups that would allow the conjugation of a homing device were developed [41][42][43][44][45][46]. Some of these functionalized analogues have been recently used for the preparation of antibody–drug conjugates (ADCs) and peptide–drug conjugates (PDCs) [46][47][48][49][50][51

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

• >70% by 2030. To effectively combat the menace of cancer, a variety of strategies have been exploited. Among them, the development of peptide–drug conjugates (PDCs) is considered as an inextricable part of this armamentarium and is continuously explored as a viable approach to target malignant tumors

• throughout this review. Among the most intriguing navigating delivery systems that can combine the transporting vehicle and the navigating/targeting moiety in a single module are the tumor-homing peptides [32]. These peptides are exploited to assemble the peptide–drug conjugates (PDCs) which are considered

• rationally installed taking into consideration the final derivative of the cytotoxic agent to retain the original cytotoxic activity. The sections below summarize the basic design principles of peptide–drug conjugates to selectively target the malignant cells. Selecting the proper tumor-targeting peptide to

Development of novel cyclic NGR peptide–daunomycin conjugates with dual targeting property

• Andrea Angelo Pierluigi Tripodi,
• Szilárd Tóth,
• Kata Nóra Enyedi,
• Gitta Schlosser,
• Gergely Szakács and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 911–918, doi:10.3762/bjoc.14.78

• Vienna, Austria 10.3762/bjoc.14.78 Abstract Cyclic NGR peptides as homing devices are good candidates for the development of drug conjugates for targeted tumor therapy. In our previous study we reported that the Dau=Aoa-GFLGK(c[KNGRE]-GG-)-NH2 conjugate has a significant antitumor activity against both

• characterization of novel cyclic NGR peptides and their corresponding NGR-drug conjugates. Special attention was paid on the chemostability and in vitro biological activity of the compounds [17][18]. Daunomycin (Dau) was used as cytotoxic agent, attached to the NGR-derivatives via oxime linkage. The prepared

• The chemostability of cyclic NGR peptide–drug conjugates was studied under the treatment conditions used for the in vitro cytotoxicity experiments. Samples were taken at 0 min, 6 h and 72 h. The deamidation rate was evaluated by HPLC–MS. In contrast to the control conjugate (K) that showed high

Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin–GnRH-III conjugates developed for targeted drug delivery

• Sabine Schuster,
• Beáta Biri-Kovács,
• Bálint Szeder,
• Viktor Farkas,
• László Buday,
• Zsuzsanna Szabó,
• Gábor Halmos and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 756–771, doi:10.3762/bjoc.14.64

• smallest Dau metabolite obtained by lysosomal degradation is H-Lys(Dau=Aoa)-OH, which is able to bind to DNA resulting in a cytotoxic effect. A variety of oxime bond containing GnRH-III drug conjugates have been designed in our research group and their in vitro cytotoxic effects on hormone dependent human

• choice to study biological processes or to test the efficiency of drugs or drug conjugates and their cytotoxic effects. Immortal cell lines offer various benefits, for instance they are easy to handle, cost-effective and provide consistent sample and reproducible results [47]. Nevertheless, cell lines

• data of the conjugates cannot explain alone the results of their in vitro antitumor activity. Cellular uptake of the bioconjugates on MCF-7 human breast and HT-29 human colon cancer cells by flow cytometry The cellular uptake of the GnRH-III–drug conjugates was studied by flow cytometry on HT-29 and

Synthesis and biological evaluation of RGD and isoDGR peptidomimetic-α-amanitin conjugates for tumor-targeting

• Lizeth Bodero,
• Paula López Rivas,
• Barbara Korsak,
• Torsten Hechler,
• Andreas Pahl,
• Christoph Müller,
• Daniela Arosio,
• Luca Pignataro,
• Cesare Gennari and
• Umberto Piarulli

Beilstein J. Org. Chem. 2018, 14, 407–415, doi:10.3762/bjoc.14.29

• α-amanitin activity on the targeted cells. An alternative approach to the antibody targeted therapy is represented by small molecule–drug conjugates (SMDCs), where the small molecule – usually a peptide or peptidomimetic receptor ligand – avoids the drawbacks of ADCs such as high manufacturing costs

Synthesis of a deuterated probe for the confocal Raman microscopy imaging of squalenoyl nanomedicines

• Eric Buchy,
• Branko Vukosavljevic,
• Maike Windbergs,
• Dunja Sobot,
• Camille Dejean,
• Simona Mura,
• Patrick Couvreur and
• Didier Desmaële

Beilstein J. Org. Chem. 2016, 12, 1127–1135, doi:10.3762/bjoc.12.109

• developed covering all aspects of medicine. Among them, lipid drug conjugates (LDC) were especially developed for the delivery of hydrophilic drugs by covalent coupling with lipid components [3][4]. In this context we recently found that the chemical conjugation of squalene, a natural and biocompatible

Exploring monovalent and multivalent peptides for the inhibition of FBP21-tWW

• Lisa Maria Henning,
• Sumati Bhatia,
• Miriam Bertazzon,
• Michaela Marczynke,
• Oliver Seitz,
• Rudolf Volkmer,
• Rainer Haag and
• Christian Freund

Beilstein J. Org. Chem. 2015, 11, 701–706, doi:10.3762/bjoc.11.80

• release of the dendritic polymer into the cytoplasm [13]. These polymeric scaffolds have been explored well for tumor targeting by using polymer-drug conjugates or polyplexes with genes or siRNA [14], but also have the potential to inhibit protein–protein interaction in cells, by displaying multiple

Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs

• Fabrizio Chiodo,
• Marco Marradi,
• Javier Calvo,
• Eloisa Yuste and
• Soledad Penadés

Beilstein J. Org. Chem. 2014, 10, 1339–1346, doi:10.3762/bjoc.10.136

• paragraph). The ester derivatives were not detected in the EtOH washings after the GNPs precipitation (by MALDI–MS and 1H NMR) indicating that practically all the drug conjugates were linked on the gold surface. Drug quantification and release of the drug from GNPs We studied the stability of the GNPs

Preparation of new alkyne-modified ansamitocins by mutasynthesis

• Kirsten Harmrolfs,
• Lena Mancuso,
• Binia Drung,
• Florenz Sasse and
• Andreas Kirschning

Beilstein J. Org. Chem. 2014, 10, 535–543, doi:10.3762/bjoc.10.49

• ] were one of the earliest examples of folate disulfide–drug conjugates and after the conjugate is internalized by endocytosis, it was demonstrated that the endosomes exert reductive cleavage. For conjugate 7 we found that disulfide cleavage provided a thiol derivative of ansamitocin P-3 (4, AP-3) 8 with

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• (1,3-dihydro-2H-isoindole-1,3-dione, 4) substitution pattern. The isoindole structure has attracted scientists for decades and can be found in several natural and pharmaceutical compounds [2][3]. A number of structures were explored over the years and promising drug conjugates such as 5–11 could be

Antibiotic and cytotoxic peptides

• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 1144–1145, doi:10.3762/bjoc.8.127

• the conventionally applied antibiotics. Consequently, the search for new antibiotically active compounds is of premier importance. On the other hand, highly cytotoxic peptides and peptide analogues, such as monomethyl auristatin E, are used as the “warhead” in antibody–drug conjugates for tumor