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

• 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

• free NH3+ of the first alanine residue contribute directly to the binding of survivin. P-T120 recruits shugoshin 1 and shugoshin 2, which in turn interact with borealin and with survivin itself, probably involving a region that is distinct from the one that interacts with P-T3-H3. B) Crystal structure

• complex. A) Lewis structure of the truncated tweezer peptide monophosphate 2b. B) Close-up of the binding motif formed by 2b (tweezer: green, butynyl ester: red) on the survivin surface encapsulating Lys-121 after MD simulation (Desmond, 100 ns, 300 K, 0.15 mM NaCl) using explicit water solvent. A

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

• formed in both pathways. Free energy computations indicate that the intermediate 12 is thermodynamically more stable by 4.9 kcal mol−1 compared to intermediate 15. The nucleophilic attack by chloride ion bifurcates into two paths, namely C1- (route a) and C2-attacks (route b) for intermediates 12 and 15

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

• to new acetophenones and 2H-chromenes, the dichlormethane extract from leaves of Melicope barbigera A. Gray (Rutaceae) afforded a mixture of the isomeric melifoliones A (1) and B (2) as well as an oxidation product of 2, whose structure was elucidated as the para-quinol 4. For an independent

• been described in the literature. Keywords: Melicope barbigera; Melifoliones A and B; new heterocyclic ring systems; new natural compounds; para-quinols; phenol oxidation; Introduction The genus Melicope is a member of the Rutaceae (Citrus family) and contains more than 200 species distributed in the

• isolated from a dichloromethane extract of leaves of Melicope barbigera A. Gray, a species endemic to the island of Kaua’i, Hawaiian Islands [2][3]. In addition, small amounts of two tetracyclic citrans were identified as a 30:70%-mixture of isomeric melifoliones A (1), and melifolione B (2) [1], both

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

• Sebastian Dominik Graf Gertraud-Kaltenecker Straße 24, D-93049 Regensburg, Germany 10.3762/bjoc.22.37 Abstract Eribulin is a synthetic analog of halichondrin B, a natural product derived from marine sponges, and has gained significant importance in oncology (as its commercial mesylate salt

• eribulin are summarized. Keywords: breast cancer; drug manufacturing; eribulin; Halaven; total synthesis; Introduction Eribulin (1) is a truncated derivative of halichondrin B (2), a complex natural product originally isolated from the marine sponge Halichondria okadai (Figure 1) [1][2][3][4][5]. Already

• within their isolation study on halichondrin B, in 1986, Hirata and Uemura showed its promising activity against murine cancer cells [6], which led to a great interest in the pharmaceutical society [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Only 6 years later, Kishi and co-workers first

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

• complex. The probe was absent in side-view classes. Synthesis of CI-994 and the Au–(CI-994) conjugate. Conditions: a) Boc2O, NEt3, THF, 0 °C to rt, 19 h, 70%; b) 4-nitrobenzoyl chloride, DIPEA, DCM, 0 °C to rt, 16 h, 74%; (c) H2, 10% Pd/C, MeOH/THF 1:1, rt, 17 h, 95%; d) AcCl, NEt3, THF, 0 °C to rt, 21 h

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• catalysis [26]. These molecules are widely found in natural products [27] and drugs, such as michellamines A and B [28], korupensamines A and B [29], diazonamide A [30], mastigophorene A [31], and the recently developed drug candidate BMS-986142 [32] (Figure 1). When a molecule contains two or more chiral

• systems will be developed with the progress of research in the future, thereby facilitating further breakthroughs in this area. Natural products with various stereogenic axes. Iridium complex-catalyzed asymmetrical synthesis of axially chiral (a) teraryl compounds 3 [40] and (b) pentaaryl derivatives 6

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

• 0.5 mM and the cultures were shaken at 17 °C for 18 hours. The cells were harvested by centrifugation and stored at −80 °C. The cell pellets were lysed in 20 mL B-PER complete (ThermoFisher) supplemented with an EDTA-free protease inhibitor tablet (Roche) according to the manufacturer’s instructions

• synthesized using the published cyclocondensation reaction (middle), and the isomeric benzo[c]acridine compound purchased from ChemDiv. B) Dose–response curves of the three compounds against the glutaminase isoform GAC. C) ORTEP diagram of the X-ray crystal structure of the material synthesized according to

Concept-driven strategies in target-oriented synthesis

• David Yu-Kai Chen,
• Chao Li and
• Yefeng Tang

Beilstein J. Org. Chem. 2026, 22, 451–454, doi:10.3762/bjoc.22.32

• radical cyclization (prostaglandin D2 metabolite, Jun Huang et al.), reductive cyclization cascade (aglacin B, Jina Xiao, Yu Peng et al.), electrochemical cyclization (review, Bin Li, H. N. C. Wong, Xiao-Shui Peng et al.), photochemical reactions (review, Shao-Min Fu, Bo Liu et al.), carbene insertion

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• bioactive trans-(+)-taxifolin. The currently most widely applied synthetic method for trans-(±)-taxifolin and its derivatives (a) and the new method via Darzens reaction reported in this work (b). Darzens reaction of 2 with various arylaldehydes under the optimized conditions. Reaction conditions: 2 (0.81

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

• +/HER2−, Ki-67 low), luminal B (ER+/PR+/HER2+ or HER2−, Ki-67 high), HER2-positive, triple-negative (lacking ER, PR, and HER2 expression), and triple-positive (ER+/PR+/HER2+) subtypes [7]. Among these, breast cancer accounts for 10–20% of triple-negative breast cancer (TNBC) cases [8]. Notably, TNBC

• % probability, b) and c) show Se···Se and Se···C intermolecular interaction in compound. DFT optimised structure of compounds a) 7 and b) 8. HOMO, LUMO, and the energy gap of the compounds: a) 7 and b) 8. Mulliken atomic charge of the compounds: a) 7 and b) 8. MEP analysis of the compounds: a) 7 and b) 8. log

• concentration (µM) vs cell viability (%) of compounds of a) 7 and b) 8. Significant difference of control vs concentration: a) compound 7, b) compound 8. 2D and 3D binding interaction of active (1M17) EGFR tyrosine kinase and synthesised compounds: a) 7 and b) 8, c) 2D interaction of crystal structure 1M17 and

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

• ]arenes by joining propargyl/2-azidoethyl and p-amino groups on a common platform. Parts of 1H,13C HMBC spectra of calixarenes 12 (a) and 13 (b) recorded in CDCl3 solutions at 600 MHz. Red lines show the key correlations between signals from the calixarene narrow-rim substituents and aromatic units

• . Molecular structures of partially nitrated calixarene 16 (a) and exhaustively nitrated calixarene 15 (b). Two projections shown in each case and thermal ellipsoids are drawn at a 50% probability level. Planar and energy-minimized structures (with CHCl3 molecule included and triazole groups highlighted) of

• isomeric homodimers of tetraurea 49 (a); structure of tetratosylureacalix[4]arene 52 (b); planar structure of heterodimer 49·52 (c); fragment of the 1H NMR spectrum of calixarene 49 in CDCl3 (d); fragment of the 1H NMR spectrum of an equimolar mixture of calixarenes 49 and 52 in CDCl3 (e). All spectra were

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

• Maryna V. Kachaeva Agnieszka B. Olejniczak Marta Denel-Bobrowska Victor V. Zhirnov Yevheniia S. Velihina Stepan G. Pilyo Volodymyr S. Brovarets Department of Chemistry of Bioactive Nitrogen-Containing Heterocyclic Bases, V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, National

• antiproliferative and cytotoxic activity against the tested NCI60 cancer cell lines. Also, several other 7-(1,4-diazepan)- and 7-piperazine-substituted [1,3]oxazolo[4,5-d]pyrimidines (structures A and B in Scheme 1) showed cytotoxic activity in the micromolar concentration range against most breast cancer cell

• combination of the [1,3]oxazolo[4,5-d]pyrimidin-7-amine fragment (structures A and B) with cytisine, glucamine, and aminoethylamine represents a promising strategy for the rational design of multifunctional hybrids with improved biological activity, water solubility, lower toxicity and target engagement

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• consists in the simultaneous generation of two reactive intermediates: terminal alkene A and N-methylazomethine ylide B, and final [3 + 2] cycloaddition. It was found that the latter approach depends on CH-acidity of the active methylene compounds and performs well with the acidic substrates in the range

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• ]helicenes 6a,b hinders their practical applications. The CD spectra of optically pure 5a,b and 6a,b were recorded (Figure 5A), and compared with reported analogous oxaza[7]helicenes [49], and spectra obtained from TD-DFT to assign their absolute configurations [27]. The absolute configurations in the first

• and second fractions of the chiral HPLC analysis were assigned as the (P)- and (M)-enantiomers, respectively, for all 5a,b and 6a,b. As expected, the increase in helical length (n) from 7 to 8, 5a and 5b exhibited more red-shifted maximum |gabs| values at around 350 nm, whereas 6a and 6b showed values

• around 290–300 nm for both enantiomers (Figure 5A). High |gabs| values have also been reported for π-extended helical nanographenes featuring aza[7]helicene subunits [65]. Subsequently, CPL spectra of (P/M)-5a,b and (P/M)-6a,b were measured to evaluate the potential of these oxaza[n]helicenes as chiral

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

• of CeO2 to attack the carbonyl carbon, leading to cleavage of the C–N bond (B). Subsequent nucleophilic attack of the octoxide anion on the activated carbonyl center (C) then furnishes the ester product. Later, the same group found that niobium could also serve as a heterogeneous Lewis acid catalyst

• understanding of amide reactivity but also inspire the future development of broadly applicable, efficient, and environmentally sustainable strategies for amide transformation. a) Resonance structure of amide. b) Concept of twisted amides. c) Transition-metal-catalyzed activation of twisted amides. d) Concept

• . Esterification of N,N-dimethyl amides via electrophilic generation of acyl iodide intermediates. Transamidation of DMAc promoted by KOt-Bu. a) LiHMDS-mediated transamidation of tertiary amides. b) Computed reactivities of selected amides. c) Rate-determining step of the LiHMDS-mediated transamidation. d) LiHMDS

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• framework is impossible is one of the ways to improve properties of ORCA. Feasibility of the synthesis of rigid 3b,4,5,6,6a,7-hexahydropyrrolo[2',3':3,4]pyrrolo[1,2-c][1,2,3]triazole and 3b,4,5,6,6a,7-hexahydropyrrolo[2',3':3,4]pyrrolo[1,2-b]pyrazole ring systems with incorporated nitroxide moiety from 2

• sulfonate group, respectively [24]. The 1H NMR spectra of 3a,b,d–f (Zn/CF3COOH system in CD3OD) showed appearance of a singlet of methanesulfonate hydrogens in the region from 2.78 to 3.17 ppm. The NMR spectra were not recorded for 3c because of heavy resinification upon the sample preparation. The

• catalytic system comprising PPh3, CuI, and Pd(PPh3)2Cl2. This procedure afforded alkynones 6a,b in the yields of 75% and 44%, respectively (Scheme 3). In the IR spectra of 6a,b intense bands were observed at 2212–2214 and 1645–1647 cm−1, assigned to vibrations of the triple bond, and the conjugated carbonyl

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

• →5 ring contraction can be found in the family of spirocyclic C15-sesquiterpenes, such as β-vetivone B (11, see Scheme 2B) [57][58][59][60]. The linear precursor farnesyl pyrophosphate (9) is first cyclised by germacrene A synthase (GAS) to its name-bearing product 10. From here, protonation by

• framework and ring contraction (10b). From here, follow up oxidations and olefin isomerisation afford β-vetivone B (11), a constituent of aromatic vetiver oil. Finally, in the biosynthesis of the antibiotic pleuromutilin (13) [61][62][63] a similar ring contraction takes place (see Scheme 2C). Cyclisation

• found in pseudolaric acid B (14) biosynthesis [64][65]. In this case, the linear precursor 12 is first cyclised to give intermediate 14a akin to the α-terpinyl cation (see Scheme 3). From here, quantum chemical calculations indicate that the subsequent 1,2-alkyl shift and olefin cyclisation occur in a

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

• -adducts 4a–e, the carbon signals of ring A (Figure 1) appear at δC 44.8–45.0 ppm (CH21), 27.3 ppm (CH22), and 25.2 ppm (CH23). Ring B carbons resonate at δC 67.7–67.8 ppm (CH4), 46.3–46.4 ppm (CH5), and 58.2–58.3 ppm (CH6). The carbonyl carbons of ring C and the barbiturate ring appear at δC 150.0, 169.3

• –169.4, 171.2–171.5, 175.5–176.8, and 176.4–177.9 ppm. The spiro carbon appears at δC 70.1–70.3 ppm. For diastereomers 4f–p, the 13C NMR spectra proved more informative than the 1H NMR spectra, clearly displaying a duplicate set of nearly all signals. The chemical shifts of carbons in rings A, B, and C

A mild and atom-efficient four-component cascade strategy for the construction of biologically relevant 4-hydroxyquinolin-2(1H)-one derivatives

• Dmitrii A. Grishin,
• Kseniia I. Sharkovskaia,
• Ilya G. Kolmakov,
• Daria A. Ipatova,
• Rostislav A. Petrov,
• Nikolai D. Dagaev,
• Dmitry A. Skvortsov,
• Maria G. Khrenova,
• Valeriy V. Andreychev,
• Sergei A. Evteev,
• Yan A. Ivanenkov,
• Roman L. Antipin,
• Olga А. Dontsova and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2026, 22, 244–256, doi:10.3762/bjoc.22.18

• Meldrum's acid anion, which then undergoes Michael addition to iminium zwitterion A. The resulting Michael adduct B eliminates deprotonated ʟ-proline through proton migration, yielding arylidene Meldrum's acid C. Simultaneously, ʟ-proline facilitates the formation of the 4-hydroxyquinolin-2-one anion, which

• activity studies. А) In vitro antibacterial activity using the E. coli ΔtolC strain with modified reflux system; B) in vitro antibacterial activity using the E. coli lptD mut strain with modified cell membrane; ery – erythromycin, lev – levofloxacin. Previously reported and newly developed 3-(4-hydroxy-2

• -oxo-1,2-dihydroquinolin-3-yl)-3-arylpropanoic acid derivatives. Retrosynthetic analysis: two alternative approaches to target compounds. Two-stage synthesis A) and one-stage one-pot synthesis B) of 6-halogen-4-hydroxyquinoline-2(1H)-ones 2a–c. Previous synthetic attempts toward the target chemotype

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

• molecular design approaches for TADF include twisted donor–acceptor structures (for example, carbazole or phenoxazine as donors and triazine, nitrile, or carbonyl groups as acceptors) as well as B/N multiresonance frameworks [30][31][32]. These strategies have been successful in achieving efficient triplet

• , 478.1682. a) Single-crystal structure of 1, b) HOMO distribution calculated on the crystallographic geometry, and c) LUMO distribution calculated on the crystallographic geometry. Photophysical properties of 1 in solvents of varying polarity: a) UV–vis absorption spectra and b) fluorescence emission

• spectra (excitation wavelength: 365 nm). Fluorescence and phosphorescence spectra of 1 in THF (excitation wavelength: 365 nm). a) Steady-state and delayed emission spectra of 1, b) room-temperature emission lifetimes monitored at 550 nm and 600 nm, c) time-resolved emission spectra, d) temperature

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

• method for the generation of helical chirality primarily involves cycloaddition and central/axial to helical chirality transfer reactions [31] (Figure 1A and B). In addition to this, a parallel strategy also offers a promising approach to achieving configurationally stable helicenes via terminal peri

• induction of helical chirality which majorly relies on the π extension of organic scaffolds via annulation/cycloaddition and B) central/axial to helical chirality conversion. C) Induction of helical chirality in [4]helicene via terminal peri-functionalization. D) Induction of helical chirality in [5

Base-promoted deacylation of 2-acetyl-2,5-dihydrothiophenes and their oxygen-mediated hydroxylation

• Vladimir G. Ilkin,
• Margarita Likhacheva,
• Igor V. Trushkov,
• Tetyana V. Beryozkina,
• Vera S. Berseneva,
• Vladimir T. Abaev,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2026, 22, 192–204, doi:10.3762/bjoc.22.13

• , Leuven B-3001, Belgium 10.3762/bjoc.22.13 Abstract Solvent-dependent transformations of polysubstituted 2-acetyl-2,5-dihydrothiophenes to the corresponding 2-hydroxy- or deacetylated derivatives are described. The treatment of a methanolic solution of the dihydrothiophene substrates with sodium

• phenols [25]. Hocking has described the oxidation of o-hydroxyacetophenone and some benzophenones with an aqueous alkaline hydrogen peroxide solution [26]. The key steps of oxidation of ketones into phenols include: a) nucleophilic addition of the hydroperoxide anion to the carbonyl carbon; b) [1,2]-aryl

• (retention time 6.905‒6.961). One of these peaks can be assigned to the product 2a, while the other peak showed that the deacylated product 3a is formed during the transformation with subsequent oxidation by sulfur in the oxidation/reduction step to form 2,5-dihydrothiophene 1-oxide 2a′ (Figure 1, a and b

Streptoquinolines A and B, new antibacterial meroterpenoids produced by Streptomyces sp. TMPU-A0679

• Akiho Yagi,
• Hitomi Tomura,
• Ami Konno and
• Ryuji Uchida

Beilstein J. Org. Chem. 2026, 22, 185–191, doi:10.3762/bjoc.22.12

• -resistant enterococci (VRE), two new meroterpenoids, streptoquinolines A (1) and B (2), were isolated from a culture of terrestrial Streptomyces sp. TMPU-A0679. The structures of 1 and 2 were elucidated based on spectroscopic analyses, including NMR and MS, and were found to consist of a drimane-type

• B (2) (Figure 1). Compounds 1 and 2 possessed a unique skeleton consisting of a drimane-type sesquiterpene fused with a quinoline moiety and both exhibited potent antibacterial activity against Gram-positive bacteria. This study describes the production, isolation, structural elucidation, and

• preparative HPLC, yielding streptoquinolines A (1, 7.50 mg) and B (2, 8.05 mg). The physicochemical properties of 1 and 2 are summarized in Table 1. Compounds 1 and 2 showed characteristic absorption maxima at 200–202, 214, 231–234, 312, and 349–350 nm in UV spectra. Common IR absorption bands at 3414–3427

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

• and 0.1% phosphoric acid in the ratios 35:65 and 25:75, v/v for the distribution coefficient and stability experiments, respectively. The ChemStation software (Version B.04.03, Agilent Technologies) was used for instrument control and data collection. Computational chemistry DFT calculations were

• 1.0 Hz before Fourier transformation. Spectra were processed with MestReNova. Synthesis of 25CN-NBOH·HCl (1·HCl). a) 2C-CN is available in 4 steps from 2C-H [12]: 1) TFAA, TEA, DCM; 2) TiCl4, dichloromethyl methyl ether, DCM; 3) NH2OH, HCl, EtOH, then Ac2O; 4) NaBH4, EtOH, then HCl. b) Salicylaldehyde

• , oxygen atoms red, and chloride ion green. b) The crystal packing reveals alternating layers, a polar layer with hydrogen bonds (black dashed lines), and a hydrophobic layer with π–π-stacking (grey dashed lines). SCXRD and XRPD spectra of different preparations of 1·HCl. Blue: SCXRD spectrum of 1·HCl. Red

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• , thereby creating water-soluble derivatives of this ancient dye. A) UV–vis spectra of 6,6’-dibromo-5,5’,7-indigotrisulfonic acid trisodium salt (10) (10 μM) in aqueous solution at different pH values. B) UV–vis spectra of 6,6’-dibromo-5,5’-indigodisulfonic acid disodium salt (9) (10 μM) in aqueous solution

• at different pH values. A) Generalized synthetic scheme for several previous syntheses of 6,6’-dibromoindigo. B) The synthetic scheme for 6,6’-dibromoindigo described in this work. Synthetic scheme for the preparation of 6,6’-dibromoindigo from p-bromotoluene (5). Nitration of p-bromotoluene (5

• ) yields a mixture of regioisomers 3 and 7. Benzylic bromination of 4-bromo-2-nitrotoluene (3). A) Treatment of 4-bromo-2-nitrobenzyl bromide (6) with DMSO did not yield the alkoxysulfonium ion intermediate 8. B) Silver nitrate-mediated Kornblum oxidation yields 4-bromo-2-nitrobenzaldehyde (4) in fair