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

• interaction by roughly one order of magnitude (from 1 µM to 120 nM Kd). For further structural proof we attempted co-crystallization of survivin with our new tweezer H3 conjugate. Unfortunately, crystallization of full length survivin 1–142 was difficult to reproduce and often resulted in low-quality crystals

• . Hence, we designed the truncation constructs 1–122, 1–127 and 1–134 that shorten the flexible C-terminal helix of survivin. All new constructs showed a much better expression and crystallization behavior. Fluorescence polarization measurements with the FITC-labeled H3 peptide confirmed that constructs 1

• the included side chain protons [12][13]. HPLC–HRMS analysis finally produced a single chromatographic signal with clean molecular ion peaks for [M + 2H]2+ and [M + 3H]3+. The high purity of 2a was further demonstrated by successful co-crystallization of this tweezer peptide conjugate with survivin

Experimental and DFT studies on the regioselective methanolysis of 5-azido-9-oxabicyclo[6.1.0]nonan-4-yl 4-nitrobenzoate isomers

• İlknur Polat,
• Selçuk Eşsiz and
• Emine Salamci

Beilstein J. Org. Chem. 2026, 22, 547–556, doi:10.3762/bjoc.22.40

• and 9b, respectively, but all attempts to separate the isomeric epoxides 9a and 9b by column chromatography or crystallization failed. Eight-membered rings are known to preferentially adopt boat-chair conformations, which minimize torsional and transannular strain [24]. To further rationalize the

• :37 ratio (1H NMR), but all attempts to separate the isomeric epoxides 9a and 9b by column chromatography or crystallization failed. Acetylation and methanolysis of the mixture of isomeric azidobenzoate epoxides 9a and 9b with HCl(g) in MeOH In a similar manner as described in the literature [13], a

Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• 2, received via fractional crystallization. However, the oxidation procedures were performed with mixtures of both isomers with the aim to get the quinols 3 and 4. Results and Discussion Structure of compound 4 Compound 4 was isolated from a dichloromethane extract of the leaves of M. barbigera as a

• during crystallization, was identified within solvent-accessible voids in the crystal lattice. Due to its high level of disorder, the DMF molecule was removed computationally using the SQUEEZE routine implemented in the PLATON software package [18]. The final structural model clearly establishes the

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• , 110 °C, crystallization. (b) i. DIBAL-H, THF/toluene, −10 °C; ii. Ph3PCHCO2Et, benzoic acid, DCM, 50 °C; (c) i. TESOTf, 2,6-lutidine, DCM, 0 °C; ii. 5 mol % Pn-Bu3 (5 mol %), THF, 50 °C; (d) DIBAL-H, DCM, 20 °C; (e) i. (−)-DET, Ti(OiPr)4, DCM, 0 °C; ii. DMP, DCM, 0 °C; iii. MePPh3Br, NaHMDS, THF, 0 °C

• , EtOAc, 15 °C; ii. CrCl2, NiCl2, 1-bromo-2-trimethylsilylethene, DMSO, MeCN, 30 °C; iii. AcOH, H2O, 95 °C, crystallization; iv. TBDMSOTf, 2,6-lutidine, MTBE, 30 °C, crystallization; v. NIS, MeCN, toluene, TBDMSCl, 35 °C; (k) DIBAL-H, 2,6-di-t-Bu-4-hydroxytoluene, toluene, 65 °C. Below: Reaction sequence

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• methanesulfonic acid as first reported by Floriani et al. [17] and Sessler et al. [18]. This condensation reaction produces several PCP isomers, including the targeted pre-organized α,α,α,α-isomer, which is isolated by crystallization from glacial acetic acid, followed by removal of the acetic acid using a

• several ultrasonic washings with aqueous ammonium chloride, as previously described by Verma et al. [51]. At this stage, chromatographic techniques, crystallization, and successive washing steps all failed to yield the pure compound due to the persistent presence of DBU. Additionally, the use of a small

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

• removed in vacuo, the residue was treated with water, and the solid precipitate was filtered off and dried. The formed compounds 1–9 were purified by crystallization from acetonitrile [17]. Spectral data Analytical and spectral data, IR, 1H, 13C NMR and LC–MS spectra of compounds 1–9 are given in

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

• mixture by preparative TLC or column chromatography. Notably, compounds 4a, 4e, and 4k were purified by crystallization. Detailed synthetic and isolation procedures for all compounds are provided in Supporting Information File 1. We regret to state that when forming a mixture of diastereomers, we were

Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• rigid hydrogen-bonded [26] or ionic networks [13], and utilizing crystallization [27] or confinement environments [28] to restrict molecular motion. These strategies have been implemented in various systems, such as aromatic diketones, diimides, urea/amides self-assembled solids, and carbonyl-containing

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• ). Notably, the crystal structure shows that there are no water molecules of crystallization present, nor are any other solvent molecules incorporated into the crystal packing. When comparing the diffractogram obtained by SCXRD (Figure 3, green) with that obtained by X-ray powder diffraction (XRPD) of 1·HCl

• thermogravimetric analysis (TGA) curves did not show any significant mass loss prior to the melting point, further strengthening the conclusion that 1·HCl is not present as a hydrate or solvate upon crystallization from EtOH. Characterization of 25CN-NBOH (1) in solution 1·HCl displayed a thermodynamic solubility

• , and no water molecules of crystallization or other solvent molecules were incorporated into the crystal packing. XRPD corroborated these findings, indicating a high degree of crystallinity and the presence of a single polymorph in the current work. Product 1·HCl was stable in aqueous solution over an

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

• precipitated from the reaction, which allowed it to be easily isolated and purified by crystallization from MeCN. Diastereomer 4att was obtained from the filtrate also by crystallization from MeCN. Column chromatography allowed us to isolate octahydropyrido[1,2-a]pyrimidinones 4atc, 4acc in an individual form

Unique halogen–π association detected in single crystals of C–N atropisomeric N-(2-halophenyl)quinolin-2-one derivatives and the thione analogue

• Mai Uchibori,
• Nanami Murate,
• Kanako Shima,
• Tatsunori Sakagami,
• Ko Kanehisa,
• Gary James Richards,
• Akiko Hori and
• Osamu Kitagawa

Beilstein J. Org. Chem. 2025, 21, 1748–1756, doi:10.3762/bjoc.21.138

• racemic quinolinones rac-1 in Figure 2 (single crystals of rac-2a were obtained from slow evaporation of hexane/methanol (1:1) mixture at room temperature) [37]. That is, in contrast to rac-1, in which homochiral layered polymer chains were formed, crystallization of quinoline-2-thione rac-2a led to the

• unstable and standing for a long period in the solution state resulted in several decomposed products). Conclusion We found that crystallization of racemic and optically pure C–N atropisomeric N-(halophenyl)quinolin-2-one derivatives led to the formation of homochiral layered polymer chains, which consist

Ambident reactivity of enolizable 5-mercapto-1H-tetrazoles in trapping reactions with in situ-generated thiocarbonyl S-methanides derived from sterically crowded cycloaliphatic thioketones

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Marcin Palusiak,
• Heinz Heimgartner,
• Marta Denel-Bobrowska and
• Agnieszka B. Olejniczak

Beilstein J. Org. Chem. 2025, 21, 1508–1519, doi:10.3762/bjoc.21.113

• , attributed to the Me‒S and Me‒N moieties were found at 1.86 and 3.86 ppm, respectively, and they were accompanied by two multiplets, attributed to two CH units of the adamantane ring, found at 2.37‒2.44 and 2.47‒2.54 ppm. To our delight, simple fractional crystallization from hexane with small admixture of

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• + ions during crystallization. Aiming at developing a protocol for gold recovery from e-waste and gold-bearing scrap based on the use of β-CD, extraction parameters such as the ratio of β-CD to KAuBr4, and the countercation of the gold salts were explored [51]. When the range of the β-CD-to-KAuBr4 ratio

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

• Krishna Pandey,
• Lucas X. Orton,
• Grayson Venus,
• Waseem A. Hussain,
• Toby Woods,
• Lichang Wang and
• Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

• further understand the complexation with metal cations, separate co-crystals of HIM 1 with LiBArF20 and NaBArF24 were obtained by vapor diffusion of diethyl ether into acetone. The details of the co-crystallization experiment are provided in the crystallographic information section of Supporting

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

• +···−O3SO contacts with distances in the 4.4–5.4 Å range which suggests they play a supporting role during crystallization. Measurement of the self-association of C1 Before proceeding to investigate the molecular recognition properties of C1 by ITC, we wanted to determine whether C1 undergoes self

Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• -phenacenes for clarifying the different solid-fluorescence behavior between the parent and fluorinated phenacenes. Although we have extensively examined crystallization of F8-phenacenes, no single crystal suitable for an X-ray diffraction analysis was obtained. The crystalline structural analysis is still

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• in P-1 and the molecules pack in a different arrangement, where the double bonds are neither coplanar nor parallel. This product was obtained from propan-2-ol, which may have influenced the crystallization kinetics. The reactive packing mode of Cl2B is enhanced by the hydrogen bonding where the ester

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• separated using chiral resolution. This involves separating the two enantiomers by converting the racemic mixture into a pair of diastereoisomers with the help of a chiral compound. The resulting diastereoisomers can be separated based on their physical properties using crystallization, distillation, or

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• , although the synthesis and characterization (particularly crystallization) of low-symmetry structures remains challenging [227][231][232]. Likewise, COFs hosting chiral organocatalysts are known (Figure 6B) [226][233]. Frameworks are well-suited to hosting opposing reactive functionalities (e.g., acids and

• therefore can be subjected to automated and high-throughput crystallization studies and, with Szczypiński, Slater, Cooper and co-workers, we were able to isolate all five calculated lowest-energy conformers of cage 1 in the solid state (see crystal cavity heights marked under conformers in Figure 9A) [40

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• structural analysis were obtained by crystallization from MeOH (5a), EtOH (5b), or DMFA (6b, 6c, and 7a). Single crystals of a suitable size were glued to the top of a glass fiber in a random orientation. The preliminary unit cell parameters were determined using three runs at different ω angle positions

Synthesis and characterizations of highly luminescent 5-isopropoxybenzo[rst]pentaphene

• Islam S. Marae,
• Jingyun Tan,
• Rengo Yoshioka,
• Zakaria Ziadi,
• Eugene Khaskin,
• Serhii Vasylevskyi,
• Ryota Kabe,
• Xiushang Xu and
• Akimitsu Narita

Beilstein J. Org. Chem. 2025, 21, 270–276, doi:10.3762/bjoc.21.19

• variety in crystallization, including differences in shape, length, and width, b) rod-like crystals with lengths of hundreds of nanometers, c) rod-like crystals with lengths of hundreds of micrometers, and d) longer wire. Synthesis of BPP-OiPr 3 and BPP-dione 4. Reaction conditions for the synthesis of

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• synthesis of 1 using a Ni-mediated Yamamoto coupling reaction and the simultaneous crystallization of its two different conformers from the same solution. Expanding the π-skeleton of 1 through a Barton–Kellogg reaction followed by a subsequent Scholl reaction resulted in a new polycyclic arene (3 in Figure

• presents an apparently twisted central benzene ring with large torsion angles: C1–C2–C3–C4 at 19.5°, C3–C4–C5–C6 at 21.8°, and C5–C6–C1–C2 at 21.5°. The crystallization of the two conformers of 1 in different polymorphs suggests the flexibility of its polycyclic skeleton, with both its [5]helicenoid and

• HOMO level (−5.47 eV). Conclusion In conclusion, we developed a new synthesis of tris(4,5-dehydro-2,3:6,7-dibenzotropone) (1) through a Ni-mediated Yamamoto coupling reaction. Upon crystallization from the same solution in hexane, this compound yielded colorless and yellow crystal polymorphs, adopting

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• POM observations and their room temperature behaviors (no crystallization is observed even at low temperature, except for F12). Compounds with shorter alkyl chains, F3, F4, and F5, possess almost the same clearing temperatures near 190 °C, whereas from F6 to F12, the clearing temperature gradually

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• palladium catalyst. Aminofluorination of alkenes in the synthesis of enantiomerically pure β-fluorinated piperidines. PMB = para-methoxybenzene, athe ee value was determined after Cbz group was replaced with tosyl group, bthe value in brackets corresponds to the ee value after crystallization. PG