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

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

Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

• Kadri Kriis,
• Harry Martõnov,
• Annette Miller,
• Mia Peterson,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2026, 22, 151–157, doi:10.3762/bjoc.22.8

• ). This suggests that possibly the halogen bond plays a role in the emergence of the stereoselectivity of the reaction. The reaction with the similar quinidine derivative with reduced double bond (catalyst B) was slower and less selective affording the opposite enantiomer in low enantiomeric purity (14

Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

• calculation. (b) Optimized structure of R-Pt by DFT calculation. Emission spectrum of 1 wt % PMMA matrix (R-Pt) (λex = 300 nm). (a) CD spectra of S/R-Pt in 1.0 × 10−5 M dichloromethane solution. (b) CPL spectra of 1 wt % PMMA film (λex = 300 nm). Synthesis of the binaphthyl-based ligand and the platinum(II

Symmetrical D–π–A–π–D indanone dyes: a new design for nonlinear optics and cyanide detection

• Ergin Keleş,
• Alberto Barsella,
• Nurgül Seferoğlu,
• Zeynel Seferoğlu and
• Burcu Aydıner

Beilstein J. Org. Chem. 2026, 22, 131–142, doi:10.3762/bjoc.22.6

• 436 nm, 461 nm and 403 nm, respectively, and the peak at the longer wavelength seen before interaction with CN− disappeared. The peaks for 2a–b+CN− arise from the HOMO−1→LUMO transitions, while for 2c+CN− are contributed from the HOMO−2→LUMO transitions, with the contributions ≈94–99%. Considering the

• dyes 2a (a), 2b (b), and 2c (c); Photographs of dyes in the given solvents of different polarities under ambient light (d) c = 10 μM. Absorption spectra of dyes 2a (a), 2b (b), and 2c (c) upon addition of 20 equiv of anions in DMSO; photographs of dyes with/without addition of anions under ambient

• light (d) (c = 10 μM). Absorption spectra of titrated dyes (2a–c) with up to 50 equiv of CN− (a) 6:4, (b) 7:3, and (c) 4:6 in DMSO/H2O (v/v) (c = 30 μM). Partial 1H NMR spectral change of 2b (c = 10 mM) after up to 2 equiv of TBACN (c = 1 M) in DMSO-d6. Optimized geometries of 2a–c and 2a–c+CN− obtained

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• geometrically calculated positions and included in the refinement in the “riding” model. Crystal of 2, C6H2Cl3N3O2, M = 254.46, monoclinic, space group P21, at 100.4(5) K: a = 11.6233(2), b = 6.39530(10), c = 13.1586(2) Å, β = 96.5730(10), V = 971.71(3) Å3, Z = 4 (two independent molecules), Dcalc = 1.739 g·cm

• . The final R1 was 0.0260 (I > 2σ(I)) and wR2 was 0.0655 (all data). Crystal of 3, C7H5Cl3N2O4, M = 287.48, monoclinic, space group P21/n, at 100.00(10) K: a = 8.3468(3), b = 6.1819(2), c = 21.2056(6) Å, α = 90, β = 93.234(3), γ = 90o, V = 1092.45(6) Å3, Z = 4, Dcalc = 1.748 g·cm−3, μ(MoKα) 7.658 mm−1

• ) K: a = 11.4834(6), b = 11.0564(5), c = 23.7834(10) Å, α = 90, β = 91.057(4), γ = 90o, V = 3019.1(2) Å3, Z = 8 (two independent molecules), Dcalc = 1.595 g·cm−3, μ(Mo Kα) 5.651 mm−1, F(000) = 1485.2, 21310 reflections measured (7.44° ≤ 2Θ ≤ 139.94°), 5708 unique (Rint° = 0.0984, Rsigma° = 0.0556

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• other functionalities. The following sections highlight representative examples of both modes in complex molecule synthesis. Total synthesis of (±)-keramaphidin B by Baldwin, 1996 Although the methodologies for aromatic ring hydrogenations have only recently flourished, the reduction of aromatic rings

• to obtain saturated aliphatic or heterocyclic rings and their subsequent application in the total synthesis of natural products has a long history. A brilliant early work is Baldwin's total synthesis of the macrocyclic diamine natural product (±)-keramaphidin B in the year of 1996 (Scheme 9) [71][72

• 81 was prepared via a Polonovski–Polish reaction and isomerization, which, when adopting the proper conformation, spontaneously underwent an intramolecular [4 + 2] cycloaddition to construct the unsaturated bridged ring of (±)-keramaphidin B in a single transformation. Subsequently, the iminium ion

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• suggested that the developed reaction would be applicable to halichondrin synthesis. The Zr/Ni-mediated ketone synthesis was then applied to the total synthesis of homohalichondrin B (58, Scheme 11B). Using a fragment corresponding to homohalichondrin B, the coupling reaction furnished ketone 57 in 82

• synthesis of homohalichondrin B (58). This synthetic strategy proved broadly applicable to multiple members of the halichondrin family, enabling the efficient synthesis of nine natural products: halichondrins A–C, norhalichondrins A–C, and homohalichondrins A–C. The Zr/Ni-mediated one-pot ketone synthesis

• group achieved the first total synthesis of cyctetryptomycins A and B by employing a zirconium catalyst (Scheme 12) [5]. The synthesis commenced with the dimerization of 3-bromotryptophan derivative 59. As an initial step, the authors sought to develop a mild and scalable method for the dimerization of

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• -hydroxyisoquinolones [36][37]. Additionally, the analyses of both HOMO and Fukui f– function shows little or no nucleophilicity at this position (Figure 2). Therefore, the formation of products 4a,b and 10k could proceed through the intermediary formation of the corresponding compounds 5 and their subsequent

• with the formation of 4a,b, as well as the formation of hydrazone product 10k exclusively in the case of the most sterically hindered diazonium electrophile leads to the conclusion that the direct electrophilic attack onto the i-position could take place in all these cases. To clarify this, we analyzed

• possibility of i-halogenation via a chain radical mechanism (Scheme 3). The initiation stage includes an oxidation of anion 2 into the corresponding radical 13 which in turn reacts with halogens to form products 4a,b and a halogen atom which can also oxidize the anion. Quantum chemical calculations revealed

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• products 28–35, 38 and 39 [56]). The yields varied considerably depending on the substrate, leading to the following conclusions: (a) unhindered ketones lacking functional groups generally react in high yields; (b) sterically hindered ketones provide products 33, 36, and 39 with low yields; (c) electron

• chlorides was also utilized in the total synthesis of (S)-jamaicamide C and laingolide B (not shown) [121][122]. Schwartz’s work on alkenylzirconium complexes revealed high-yielding, stereoretentive transformations under similar conditions (Scheme 29H) [123]. In a complementary study, Srebnik showed that

• with SOCl2, and treatment with base (Scheme 38; yields refer to the transformation of B → C) [139]. A reaction which includes a fluorine–chlorine exchange and subsequent elimination of HCl was reported by Shibata and co-workers (Scheme 39) [140]. In this reaction the AlEt2Cl has a dual role of fluorine

One-pot synthesis of ethylmaltol from maltol

• Immanuel Plangger,
• Marcel Jenny,
• Gregor Plangger and
• Thomas Magauer

Beilstein J. Org. Chem. 2025, 21, 2755–2760, doi:10.3762/bjoc.21.212

• to ethylmaltol (1) combined with the rather harsh deprotection conditions, led us to investigate other masking groups. Next, we turned towards silyl protecting groups as they offered (a) facile tuning of stability and (b) the opportunity for acid-mediated deprotection during aqueous work-up

• ethylmaltol (1) is the use of maltol (2) as the starting material, which is readily available from tree barks. Importance and synthetic approaches to ethylmaltol (1). (a) Ethylmaltol (1) is widely used as a flavor enhancer. (b) Reported syntheses. (c) One-step synthesis from naturally occurring maltol (2

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• Alexander S. Budnikov Nikita E. Leonov Michael S. Klenov Andrey A. Kulikov Igor B. Krylov Timofey A. Kudryashev Aleksandr M. Churakov Alexander O. Terent'ev Vladimir A. Tartakovsky N.D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow

• -nitrosopropane (1a) is expected to be barrierless with the formation of N-oxyl radical B. The radical B undergoes very low-barrier (ΔG≠ 5.5 kcal/mol) fragmentation with the release of NO2 molecule and formation of the final product 2a. An alternative pathway for the formation of 2a is a direct NO2 extrusion from

• ]/CPCM(MeCN) level of theory (in the case of >15 conformers, 15 most stable according to GFN2-xTB were analyzed). CV-curves of 0.01 M solutions of a) 1a (blue), b) 1f (azure), c) 1c (pink), d) 1i (yellow), e) S4 (red), f) S3 (green), g) S2 (brown), and h) S1 (orange) in 0.1 M n-Bu4NBF4 solution in MeCN