Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• 3, respectively, in a more efficient and selective way by protein engineering, we thought that germacrene A (5), whose terpene cyclases are widely found in different organisms [52], could serve as a precursor for synthesis of both 2 and 3 via a transannular cyclization process [37][53][54]. A

Using generative AI to transform peptide hits into small molecule leads

• Joshua Mills and
• Yu Heng Lau

Beilstein J. Org. Chem. 2026, 22, 672–679, doi:10.3762/bjoc.22.51

• Joshua Mills Yu Heng Lau School of Chemistry, The University of Sydney, Camperdown NSW 2006, Australia ARC Centre for Innovations in Peptide and Protein Science, The University of Sydney, Australia 10.3762/bjoc.22.51 Abstract There is a wealth of structural data on peptides that bind potential

• potential for new AI-based tools to expedite the structure-based transformation of peptide hits into small molecule leads. In this Perspective, we highlight how AI-enabled prediction and design tools can potentially span the entire workflow from peptide to small molecule: target protein structure prediction

• , peptides serve as accessible starting points for designing molecules that bind and inhibit a chosen protein target. Many enzyme targets (e.g., proteases) natively process peptides as their substrates. Peptide domains are also common motifs in protein–protein interactions, mediating the binding between

Advantages of PROTACs in achieving selective degradation of homologous protein families

• Luxi Yang,
• Xinfei Mao,
• Jingyi Zhang,
• Jing Shu,
• Wenhai Huang,
• Xiaowu Dong,
• Yinqiao Chen and
• Mingfei Wu

Beilstein J. Org. Chem. 2026, 22, 628–661, doi:10.3762/bjoc.22.49

• summarize the advantages of PROTACs in conferring selectivity toward highly homologous proteins. This focus will provide a feasible strategy for developing PROTACs that selectively target highly homologous proteins and will ultimately support future therapeutic applications. Keywords: homologous protein

• ; PROTAC; protein–protein interaction; selectivity; ubiquitination; Introduction The cell is the fundamental unit of structure and function in the human body [1][2]. More than 20,000 proteins act in concert to regulate the entire cellular life process [1]. To date, dysregulated protein function has been

• recognized as one of the leading causes of human diseases [3]. Although small-molecule inhibitors [4] remain the most widely used therapeutic agents for the treatment of disorders associated with abnormal protein activity, nearly all disease-relevant scaffolding proteins [5], transcription factors [6], and

Towards the targeted protein degradation of CK2: design and synthesis of CAM4066-based PROTACs

• Sophie Day-Riley,
• Sona Krajcovicova,
• Aryaman Raj Sokhal,
• Jan L. Venne,
• Paul Brear,
• Marko Hyvönen,
• Benjamin C. Whitehurst,
• Jason S. Carroll and
• David R. Spring

Beilstein J. Org. Chem. 2026, 22, 611–619, doi:10.3762/bjoc.22.47

• Cambridge Institute, Robinson Way, Cambridge, CB2 0RE, United Kingdom 10.3762/bjoc.22.47 Abstract Human protein kinase CK2 is a constitutively active serine/threonine kinase implicated in numerous cancers. Although ATP-competitive inhibitors such as CX-4945 show therapeutic potential, they are limited by

• binding affinity comparable to CAM4066, confirming that linker installation is tolerated and preserves key interactions in the αD and ATP sites. Keywords: CAM4066; casein kinase 2 (CK2); PROTACs; targeted protein degradation; Introduction Protein kinases form a large family of more than 500 enzymes that

• regulate key cellular processes through the phosphorylation of protein substrates. Dysregulation of kinase activity, often through mutation or altered expression, is associated with numerous malignancies [1]. CK2 (previously called casein kinase 2), a constitutively active serine/threonine kinase

Regioselective approach to 5-arylsulfonylisoxazoles and their antimicrobial activity

• Artem S. Sazonov,
• Dmitry A. Vasilenko,
• Denis V. Porfiriev,
• Yuri K. Grishin,
• Rimma A. Gazzaeva,
• Alisa P. Chernyshova,
• Maxim A. Kryakvin,
• Anna A. Baranova,
• Vera A. Alferova and
• Elena B. Averina

Beilstein J. Org. Chem. 2026, 22, 592–602, doi:10.3762/bjoc.22.45

• the expression of the katushka2S gene. When scanning, the signal from the RFP protein was displayed in green pseudocolor, and from Katushka2S in red. Most of the studied compounds demonstrated low antibacterial activity against the reporter strains, however, 3-nitrosulfonylisoxazoles 3h, 3g and

• monooxidated 3-nitrosulfonylisoxazole 4b exhibited high activity against both reporter strains. Furthermore, these samples demonstrated strong induction of the RFP reporter protein, indicating that their antibacterial action is associated with induction of the SOS response in bacterial cells (Figure 2). The

Design and synthesis of an erdafitinib-based selective FGFR2 degrader

• Yumeng Jin,
• Shidong Wang,
• Sihan Pan,
• Shuqi Huang,
• Weichen Zhou,
• Xiaohao Huang,
• Lei Zheng and
• Lingfeng Chen

Beilstein J. Org. Chem. 2026, 22, 583–591, doi:10.3762/bjoc.22.44

• design and synthesize a series of PROTAC molecules with different linkers. Screening was performed in KATO III cells with high FGFR2 expression, leading to the identification of LC-JD-6 as a potent degrader. Experimental results demonstrated that LC-JD-6 effectively induced FGFR2 protein degradation with

• -selective degrader, and for the first time confirmed its ability to degrade the membrane-bound form of FGFR2. This work provides an innovative targeted protein degradation strategy for the treatment of FGFR2-driven tumors and holds significant potential for clinical application. Keywords: CRBN; erdafitinib

• fusions [11][12][13]. Genetic amplification of FGFR2 leads to an excessive number of gene copies, resulting in over-expression of the FGFR2 protein on the cell surface. This over-abundance can cause the receptor to be constitutively active, continuously sending growth signals to the cell even without

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

• Pro26, corresponding to a previously unknown binding mode. Guided by the accessibility of survivin’s lysine residues in the CPC, a number of new promising peptide tweezers was synthesized, able to connect both binding sites on the protein. Keywords: click reaction; chromosomal passenger complex

• ; protein–protein interaction; mitosis; X-ray crystallography; Introduction The fundamental process of mitosis is controlled by a very large protein complex called the kinetochore, formed by self-assembly from hundreds of single protein components [1]. For the intricate regulation of the various phases of

• centromere protein), and the kinase Aurora B. During mitosis, Aurora B phosphorylates important components of the kinetochore and thus exerts control over key events of the whole process. The other three proteins localize the CPC during the different mitotic phases [4]. Survivin, borealin and INCENP are

Synthesis of a HDAC inhibitor–nanogold probe for cryo-EM visualization in class I HDAC co-repressor complexes

• Wiktoria A. Pytel,
• John W. R. Schwabe and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2026, 22, 480–485, doi:10.3762/bjoc.22.35

• III [3]. HDAC1, HDAC2, and HDAC3 of the class I HDACs exist in multiprotein co-repressor complexes in vivo [4]. HDAC1 and HDAC2 exist interchangeably in the CoREST, MIDAC, SIN3, NuRD, MIER, and RERE complexes, while HDAC3 exists in the SMRT/NCoR complex [4]. The protein complex partners govern the

• complex is critical, as it may significantly influence how CoREST engages with nucleosomal substrates. Nanogold particles (1–5 nm in diameter) are highly electron-dense and provide high contrast in microscopy. They have been successfully applied in immunogold electron microscopy to study protein

• on a Titan Krios microscope. A range of protein particles resembling the CoREST ternary complex were observed, with several displaying a distinct “black dot” indicative of the electron-dense gold nanoparticle (Figure S6 in Supporting Information File 1). However, as expected, Au–(CI-994) was not

Structural reassignment of compound 968, an allosteric glutaminase inhibitor

• Lindsey A. Albertelli,
• Sainabou Jallow,
• Chun Li and
• Scott M. Ulrich

Beilstein J. Org. Chem. 2026, 22, 455–460, doi:10.3762/bjoc.22.33

• of wash buffer supplemented with 10 mM imidazole. Protein was eluted into 1 mL fractions at 4 °C with wash buffer supplemented with 300 mM imidazole. A 20 µL aliquot of each fraction was analyzed by SDS-PAGE. Fractions with pure protein were pooled and the buffer was changed to 20 mM Tris (pH 8.5

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• cancer cell line. Molecular docking simulation revealed strong binding interaction and affinities towards the tyrosine kinase domain of epidermal growth factor receptor (EGFR), and the protein–ligand interaction resembles the interaction found in the co-crystallised protein–erlotinib complex. Result and

• -covalent interactions with the target protein, has a significant impact on their anticancer potential. The binding interactions of compounds 7 and 8 with the active (1M17) and inactive (4JHO) EGFR tyrosine kinase domain are summarised in Table 2. The ligand structure of compound 7 was obtained from a

• and 8 with the active (1M17) tyrosine kinase domain of EGFR The epidermal growth factor receptor (EGFR) of the active tyrosine kinase domain in complex with erlotinib was retrieved from the Protein Data Bank (PDB ID: 1M17, https://doi.org/10.2210/pdb1M17/pdb, [71]) and subjected to molecular docking

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• ]. (Multi)calix[4]arenes having (dialkyl)amino groups at the wide rims are soluble in aqueous media at physiological pHs and may be used in protein sensing [18], DNA binding/recognition [19][20][21][22][23], and cell transfection [24][25][26]. Their water-soluble guanidinium derivatives are also

Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells

• Maryna V. Kachaeva,
• Agnieszka B. Olejniczak,
• Marta Denel-Bobrowska,
• Victor V. Zhirnov,
• Yevheniia S. Velihina,
• Stepan G. Pilyo and
• Volodymyr S. Brovarets

Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27

• (Table 3). With regard to the substrate specificity of Pgp, it is highly probable that these compounds are not substrates of this protein, although compounds 1 and 7, unlike 9, appear to be capable of inhibiting it (Table 3). A low probability of oxidative metabolism of these compounds by the studied

Ring contraction and ring expansion reactions in terpenoid biosynthesis and their application to total synthesis

• Nicolas Kratena,
• Nicolas Heinzig and
• Peter Gärtner

Beilstein J. Org. Chem. 2026, 22, 289–343, doi:10.3762/bjoc.22.21

• the groups of Collado, Cane and Viaud could identify a protein titled BcBOT2 (= Botrytiscinerea BOTrydial) with similarity to microbial terpene synthases [78]. Starting from farnesyl pyrophosphate (9) BcBOT2 catalyses a rare, formal [2 + 2] cycloaddition to form the cyclobutyl carbenium ion 29a which

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• inhibition of hERG in vitro. The results are shown in Supporting Information File 1, Table S5. As can be seen from the table, the obtained results suggest that the compounds have a good intestinal absorption and medium permeability. However they are expected to have low plasma protein binding and permeation

• results obtained, docking simulations were performed for the possible interaction of spiro-adducts with actin, as the most widespread and highly conserved cellular protein. Since the initial determination of the G-actin crystal structure in complex with DNase I, many actin structures have been registered

• and nucleotide, DNaze I-binding). The structure of the 8DNH protein was retrieved from the protein data bank and the Molegro Virtual Docker 6.0 software was used to prepare it for the docking study [66][67]. The pose organizer and the ligand energy inspector tool were used to examine the docking

Conformational analysis of difluoromethylornithine: factors influencing its gas-phase and bioactive conformations

• Matheus P. Freitas

Beilstein J. Org. Chem. 2026, 22, 237–243, doi:10.3762/bjoc.22.17

• )/CBS level of theory. Color labels: H = white, C = grey, N = blue, O = red, F = electric blue. (S)-DFMO bound within the active site of human arginase I obtained from the Protein Data Bank (3GN0) (https://doi.org/10.2210/pdb3gn0/pdb, [21]). Dotted lines represent hydrogen-bonding interactions with

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• first delipidated with n-hexane. Phytic acid was extracted with 1 M HCl for 1 h. After extraction, the pH value was adjusted to 4.5 with 8.0 M NaOH, which is the isoelectric point of rice bran protein. Solids were removed via filtration and centrifugation followed by supernatant collection. The phytate

Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• ]. Some rhodanine-based derivatives act as inhibitors of hepatitis C virus (HCV) protease [19], UDP-N-acetylmuramate/ʟ-alanine ligase [20], histidine decarboxylase [21], aldose/aldehyde reductase [22], fungal protein mannosyl transferase 1 (PMT1) [23], metallo β-lactamase [24], cathepsin D [25], JNK

Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• class of interest in the search for new chemotherapeutic agents. They are known inhibitors of protein kinase C [40] and agonists of the GABA-type [41] and histamine-H3 receptors [42]. S-Allylic isothiouronium salts substituted with aliphatic groups have shown to combine high antitumor activity against

Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions

• Udyogi N. K. Conthagamage,
• Lilia Lopez,
• Zuliah A. Abdulsalam and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192

• bacteria or malignant cells like cancer) [5][6], or to influence membrane protein function and thereby control cellular behavior [7][8]. One promising approach is the development of light-activated molecules that can modulate membrane properties upon irradiation, enabling remote activation with high

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• developed for photothermal and photodynamic therapy, where their π-conjugated frameworks contribute to both imaging and therapeutic functions [19]. Some other TT-based compounds have been reported to inhibit specific carbonic anhydrase isoforms [20], protein tyrosine phosphatase 1B [21], as well as to act

Comparative analysis of complanadine A total syntheses

• Reem Al-Ahmad and
• Mingji Dai

Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178

• glial cells, rendering complanadine A a promising lead compound for neurological disorder treatment. Later, complanadine A was also identified as a lead compound for pain management by Siegel and co-workers [8]. They discovered one of its potential cellular targets as the Mas-related G protein-coupled

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• selective synthesis owing to their unprecedented catalytic activity and selectivity. Advances in the field of protein engineering have made enzymatic catalysis more amenable to enantioselective organic synthesis in the past decade. Recent advances in the development of synergistic catalytic systems

Research towards selective inhibition of the CLK3 kinase

• Vinay Kumar Singh,
• Frédéric Justaud,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Blandine Baratte,
• Thomas Robert,
• Stéphane Bach,
• Chada Raji Reddy,
• Nicolas Levoin and
• René L. Grée

Beilstein J. Org. Chem. 2025, 21, 2250–2259, doi:10.3762/bjoc.21.172

• VS-77 which has now a significant affinity toward CLK3 (IC50 = 0.3 μM). Thus, VS-77 appears as a new pan-inhibitor of the CLK family. Keywords: cancer; CLK3; kinases; molecular modelling; quinazolines; triazoles; Introduction Human protein kinases are a family comprising nearly 535

• phosphotransferases (called the human kinome) involved in specific signaling pathways which regulate cell functions (e.g., metabolism, cell cycle progression, cell adhesion, vascular function, and angiogenesis). Therefore, the dysregulation of protein kinase enzymatic activity, induced by genetic alterations as well

• as overexpression, is implicated in the pathogenesis of numerous deleterious diseases including nervous and inflammatory disorders as well as a number of malignancies [1][2][3]. Kinases are also known to be highly druggable by both allosteric and competitive inhibitors. As a consequence, protein

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• microsome (HLM) fractions were thawed on ice and diluted in 0.05 M potassium phosphate buffer (pH 7.4) to a final protein concentration of 1.25 mg/mL. Test compounds were dissolved in DMSO to create stock solutions of 5 mM. The drug concentration in the final assays was 10 μM. The assay was performed in

• conditions using Equation 5: where the HLM protein per gram of liver was equal to 25 and the liver weight per standard body was equal to 49. Testosterone was included as a positive control to confirm metabolic competence of the HLM fractions, with and without cofactors. Zero-time samples served as 100

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• F and cryptotrione have fused and spiro five-membered rings, respectively [25][26]. Strepsesquitriol bearing bridged five-membered rings was firstly synthesized by Li in 2024 [27]. The green fluorescent protein (GFP) core chromophore (o-LHBDI) displayed a potential application in organic light