Molecular tweezer–peptide conjugates disrupt the protein–protein interaction between survivin and histone H3 essential in mitosis

• Catherine Gsell,
• Philipp Rebmann,
• Karina Opara,
• Christine Beuck,
• Peter Bayer,
• David Bier,
• Ingrid R. Vetter and
• Thomas Schrader

Beilstein J. Org. Chem. 2026, 22, 557–567, doi:10.3762/bjoc.22.41

• , Otto-Hahn-Straße 11, 44227 Dortmund, Germany 10.3762/bjoc.22.41 Abstract Peptide-modified supramolecular tweezers, a promising new class of chemical tools, were designed and employed to inhibit the interaction of the BIR domain of human survivin, a member of the chromosomal passenger complex (CPC

• ), with the phosphorylated histone H3 N-terminal peptide. Fluorescence polarization measurements revealed a nanomolar affinity of the BIR domain for the peptide-tweezer, depending on the presence of lysine residue 121, as proven by the K121A mutant of survivin. Two crystal structures of C-terminally

• truncated human survivin with the peptide-tweezer molecules demonstrated that the peptide moiety binds the BIR domain as expected from the well-known published crystal structures of survivin with various peptides, but the tweezer itself, surprisingly, was bound to a putative Ca2+ ion and the side chain of

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• 91 in good to excellent yields. In the case of electron-enriched primary amides 92, the yield was decreased. Benzylamine was also a competent nucleophile, providing the corresponding amide 93 in moderate yield. Significantly, this CO2-mediated strategy also enabled chemoselective peptide bond

• benzoates 59, 185, and 51 in essentially quantitative yields. A key advantage of this protocol is its applicability to amino acid- and peptide-derived amides. Complex alcohols were successfully employed, producing the corresponding esters 186–192 in high yields without any detectable racemization or

• epimerization. Notably, the chemoselective esterification of a complex peptide, containing four distinct amide bonds and the tert-butyl nicotinate directing group, delivered the ester product 193 in 58% yield. The p-methoxybenzyl (PMB) group was recognized as an efficient activating unit for the selective

Screwing the helical chirality through terminal peri-functionalization

• Devesh Chandra,
• Sachin and
• Upendra Sharma

Beilstein J. Org. Chem. 2026, 22, 205–212, doi:10.3762/bjoc.22.14

• helical chiral entities was reported by Wang and co-workers. They reported an organocatalyzed asymmetric synthesis of phosphorus-containing chiral helicenes enabled by dynamic kinetic resolution using copper and peptide-mimetic phosphonium salts, i.e. amino acid-derived phosphonium iodide and bromide as

• nucleophilic substitution reactions (Scheme 5). A stereochemical model was proposed for the phospha-Michael addition, indicating that enantioselectivity was primarily influenced by steric effects arising from hydrogen bonding and ion pairing between the peptide mimetic phosphonium salt (PPS)-activated

Total synthesis of asperdinones B, C, D, E and terezine D

• Ravi Devarajappa and
• Stephen Hanessian

Beilstein J. Org. Chem. 2025, 21, 2730–2738, doi:10.3762/bjoc.21.210

• peptide synthetase AnaPS within the genetic machinery of these microorganisms during biosynthesis [18][19]. Subsequently, post-translational enzymatic processes mediated by prenyl transferases (AnaPT) lead to prenylation at the C4–C7 sites in the indole unit. Terezine D (6), an indole-containing

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• inhibitor doravirine [31], calcitonin gene-related peptide (CGRP) antagonist ubrogepant [32], dipeptidyl peptidase-4 (DPP-4) inhibitor gemigliptin [33]. The trifluoromethyl pyridine framework is also widely used in the development of plant protection products [34], including the fungicides fluopicolide [35

Efficient solid-phase synthesis and structural characterization of segetalins A–H, J and K

• Liangyu Liu,
• Wanqiu Lu,
• Quanping Guo and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2025, 21, 2612–2617, doi:10.3762/bjoc.21.202

• scalable methodology overcomes limitations of prior syntheses, enabling biological evaluation. Keywords: Fmoc-solid-phase peptide synthesis (Fmoc-SPPS); head-to-tail cyclization; plant cyclopeptides; Vaccaria segetalis; Introduction Cyclopeptides have garnered significant research interest owing to their

• from the high cost of the specialized resin and large solvent volumes required for dilution, coupled with DPPA's poor efficiency in forming sterically hindered peptide bonds involving residues like Val or Ile. Dahiya and Kaur synthesized segetalin C (3) via a solution-phase fragment coupling strategy

• and solid-phase approaches are viable for peptide synthesis, Fmoc-based SPPS offers distinct advantages in operational simplicity and efficiency for laboratory-scale production [20]. We therefore devised a streamlined solid-phase strategy for synthesizing the Vaccaria segetalis cyclopeptide family

Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA

• Grant D. Walby,
• Brandon R. Tessier,
• Tristan L. Mabee,
• Jennah M. Hoke,
• Hallie M. Bleam,
• Angelina Giglio-Tos,
• Emily E. Harding,
• Vladislavs Baskevics,
• Martins Katkevics,
• Eriks Rozners and
• James A. MacKay

Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193

• acid (RNA) impacts many biological processes; however, the complexities of its many roles are not completely understood. Therefore, designing tools for molecular recognition is of paramount importance. Peptide nucleic acids (PNA) show promise as a tool for selective recognition of double helical

• bonding; modified nucleobases; peptide nucleic acids; PNA–RNA triplexes; RNA recognition; Introduction RNA is a key contributor in countless biological processes. Though coding RNA has a well-known role in the central dogma of biology, most RNA is non-coding (ncRNA) and plays a multitude of roles

• oligonucleotides (TFOs) [8]. TFOs are utilized in both RNA and DNA recognition [9][10][11][12] and a particular type of TFO, peptide nucleic acid (PNA), has emerged as a promising probe for recognizing ncRNA [13][14][15][16]. The Nielsen lab first designed PNA with the N-(2-aminoethyl)glycine backbone for the

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• -bonded to a chiral peptide station. This rotaxane works as a chiroptical switch by light-induced macrocycle movement along the axle [65]. The need to understand the photochemistry of fumaramides to aid their usage in various applications led to the design of rotaxanes containing different axles. Both

Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design

• Daniil V. Khabarov,
• Valeria A. Litvinova,
• Lyubov G. Dezhenkova,
• Dmitry N. Kaluzhny,
• Alexander S. Tikhomirov and
• Andrey E. Shchekotikhin

Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161

• as the activating agent under standard peptide coupling conditions. Cleavage of the Boc-protecting group with TFA afforded the target 6-oxoindolo[1,2-c]quinazoline-12-carboxamides 7a–c (Scheme 2). 3-Aminomethylindole derivatives represent a well-established class of compounds with diverse biological

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• HSA in aqueous medium shows a characteristic oxidation wave that begins to rise around +0.5 V and significantly increases up to +1.2 V vs Ag/AgCl (Figure 3). This wave is attributed to oxidation processes at peptide bonds or specific side chains (such as cysteine, methionine, tyrosine, serine

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• the peptide chain [94]. Arylhydrazones Arylhydrazones are a class of extremely versatile photoswitches, with good fatigue resistance and thermal half-lives that span from a few hours to years (Figure 17). The common feature of arylhydrazones is the presence of a H-bond acceptor in the rotor, which

Research progress on calixarene/pillararene-based controlled drug release systems

• Liu-Huan Yi,
• Jian Qin,
• Si-Ran Lu,
• Liu-Pan Yang,
• Li-Li Wang and
• Huan Yao

Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139

• developed a SAC4A grafted self-assembled peptide hydrogel for hypoxia-responsive controlled drug release in anti-inflammatory treatment of ischemic stroke (Figure 17) [125]. Following PBS induction, the peptide hydrogel was tailored to exhibit a rheological modulus and shear-thinning behavior similar to

• -DM) or fingolimod (FTY720) in vitro. Upon local administration, the hypoxia-responsive self-assembling peptide hydrogel resulted in improved motor function and reduced inflammation in vivo. Recently, Geng and colleagues created additional binding sites by modifying the upper rim of CA4 with glucose

• responses have a broad application prospect in controlling drug release. For example, supramolecular peptide assemblies that naturally respond to pH or ion strength can be designed to include light-responsive elements or feature-specific enzyme substrates, thus utilizing two separate stimulus-response

N-Salicyl-amino acid derivatives with antiparasitic activity from Pseudomonas sp. UIAU-6B

• Joy E. Rajakulendran,
• Emmanuel Tope Oluwabusola,
• Michela Cerone,
• Terry K. Smith,
• Olusoji O. Adebisi,
• Adefolalu Adedotun,
• Gagan Preet,
• Sylvia Soldatou,
• Hai Deng,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2025, 21, 1388–1396, doi:10.3762/bjoc.21.103

• tentative biosynthesis follows that of pseudomonine, a non-ribosomally synthesized isoxazolidone produced by P. fluorescens. The previous studies on the biosynthesis revealed seven genes, three non-ribosomal peptide synthases (Pms D, E, G) and four precursor biosynthetic enzymes (Pms A, B, C, F) [23][24][25

A versatile route towards 6-arylpipecolic acids

• Erich Gebel,
• Cornelia Göcke,
• Carolin Gruner and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

• . It contains a six-membered ring and is, like its five-membered correlate, known for its secondary structure inducing properties, which are particularly useful in the design of peptide conformations. We present a new and improved way to generate enantiomerically pure pipecolic acid derivatives with

• important role as building blocks for peptide synthesis [1][2][3][4][5], as organocatalysts [6][7][8][9][10] and as enzyme inhibitors [4][11][12][13]. The incorporation of such amino acids into peptides can, for example, influence peptide conformation, the binding affinity to receptors [14], as well as

• pharmacokinetics [15][16], stability against degradation [17] and general stability [10][18] of the peptide [19]. One of those amino acids is pipecolic acid [20][21], a homolog of proline with a six-membered piperidine ring. Pipecolic acid has similar features as proline in regard to its rigid nature and turn

Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline

• Benedek Batizi,
• Patrik Pollák,
• András Dancsó,
• Péter Keglevich,
• Gyula Simig,
• Balázs Volk and
• Mátyás Milen

Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79

• silico for non-peptide malignant brain tumor (MBT) antagonist activity, showing hits on three MBT-containing proteins [35]. Although Carex brevicollis DC has been observed to have a teratogenic effect on animals [1][36], which could be linked with the presence of the two mentioned β-carboline alkaloids

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• amino acids. We synthesized two fluorinated analogs of phenylalanine, which are still unexplored in the context of peptide and protein chemistry. Furthermore, both diastereomers of trifluoroleucine were synthesized, demonstrating that the described strategy can also be applied to synthesize enantio‑ and

• -natural amino acids are pivotal in protein engineering and drug development. Over 30% of approved small‑molecule drugs today contain non‑canonical amino acid building blocks [1][2]. In peptide and protein engineering, non‑natural amino acids significantly increase the respective range of tools used to

• modify a series of peptide and protein-related properties such as stability, specificity, and folding. In this regard, fluorinated amino acids are particularly important. Incorporation of fluorinated groups into the sequence of peptides and proteins can, for instance, regulate the respective

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

• such methods are generally reported with a heterogeneous DAR, the group developed a site-specific approach leading to a homogeneous DAR 2, thanks to a photoreactive Fc-binding peptide derivative (pFcBP) containing a photoleucine (pLeu) [46]. By analyzing the X-ray crystal structure of IgG, the

• acts as a microtubule destabilizer. To ensure the stability and homogeneity of the final product, the design of the FcBP included a norbornene motif at the N-terminal end of the peptide sequence. The norbornene motif selectively reacts with a tetrazine located on the spacer-payload. This study

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• peptide carbonyl group. Both moieties result from the glyoxylate compound (Scheme 43). There are many examples in which the ester moiety opens the possibility of a further intramolecular cyclization with a nucleophile (for example, a protected amine in an Ugi/deprotection/cyclization sequence [98][99][100

Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• towards ʟ-Trp over its ᴅ-enantiomer (entries 1 and 6, Table 1). Since tryptophan fulfills many of its biological functions as a component of peptides and proteins [2][3][4][5], we also probed, if 1 can recognize tryptophan residues within peptide sequences. For this purpose, we prepared six model

• tripeptides 2–7 consisting of one tryptophan and two alanine residues. We varied the position of the tryptophan in the peptide sequence, N-terminus in 2, middle of the chain in 3, and C-terminus in 4 to check if this affects their binding by 1. To probe the importance of the N-terminal amino group in the

• , Table 2). The binding affinity of 1 towards peptide 4 is around 1.5 times higher than for the free amino acid (entry 3, Table 2). The acetylated analogues of peptides 2 and 3 – compounds 5 and 6, are bound by 1 notably weaker, with 1.8× and 1.3× lower affinities respectively (entries 4 and 5, Table 2

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• accumulation in the environment after excretion [1][6][7]. These superior properties of diazocines have been exploited in several applications such as the control of protein folding by implementation as cross-linkers between protein side chains [8] or in peptide backbones [9], as photoswitchable

Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• previously reported study investigating the biosynthesis of tenellin from Beauveria bassiana CBS110.25 [13], it was established that tenellin and a vast array of related metabolites could be synthesized through a cascade involving hybrid highly reducing polyketide synthase–non-ribosomal peptide synthetase

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• of saframycin A (1) is assembled from two molecules of ʟ-tyrosine derivative 5 and peptidyl aldehyde 6 by non-ribosomal peptide synthetases (NRPS, Scheme 1a) [15][16][17][18][19][20][21]. The pivotal NRPS module, SfmC, catalyzes iterative regio- and stereoselective Pictet–Spengler (PS)-type

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• condensation of carboxylic acids with anilines, often promoted by activating agents such as thionyl chloride or peptide coupling agents [86][87][88][89]. However, these protocols rely on environmentally harmful reagents and produce unwanted byproduct wastes. Recently, the research group of Son showcased a

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• dehydration, release of the chiral acid, and aromatization through tautomerization of intermediate Int-50 generate the desired product 195. Kwon et al. compared the effectivity of traditional biaryl phosphoric acid C30 with peptide phosphoric acid C46 in the cyclodehydration of trifluorophenylaminoacetals

• present. On the other hand, peptide phosphoric acid C46 appears to work through an alternative mode of enantioinduction, where conformational adaptation presumably limits repulsive interactions. CPA C40 was utilized in the construction of the imidazole ring of axially chiral products 200 (Scheme 59) [89