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

• ; ALFRED PASIEKA/SCIENCE PHOTO LIBRARY, No. 585105259. This content is not subject to CC BY 4.0. a. Photoredox catalytic cycles; b. absorption spectrum of photosensitizers. Therapeutic window indicates the most appropriate wavelength range to apply irradiation for biological applications. Graph

Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• Remy B. Teponno Sara R. Noumeur Marc Stadler Department Microbial Drugs, Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany and Institute of Microbiology, Technische Universität Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany Department of Chemistry

• curvupallides, and the spirostaphylotrichins [8][9][10]. Massarilactones A and B were isolated for the first time from the freshwater aquatic fungus Massarina tunicata [8], massarilactones C and D from Coniothyrium sp. associated to the succulent plant Carpobrotus edulis [11], massarilactones E, F, and G from

• [14]. Massarilactones A and B were earlier shown to exhibit antimicrobial activity against Bacillus subtilis (ATCC 6051) and Staphylococcus aureus (ATCC 29213), affording zones of inhibition varying from 12 to 19 mm at 200 μg/disk [8], while massarilactone H displayed moderate cytotoxicity against

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

• conversion of DMSO to MMS, a wide range of 4-arylquinolines can be synthesized (Scheme 8, path I) [24]. In this reaction, the persulfate ion generates the thionium ion (MMS), which is trapped by a nucleophilic aniline. The loss of methyl sulfide generates an imine intermediate B, which, in turn, reacts with

• ). Additionally, the Tiwari group developed a metal-free protocol using only K2S2O8 as an oxidant for the activation of DMSO to MMS (Scheme 8, path II) [38]. Under these conditions, an alternative mechanism arises in which the imine intermediate B, formed as previously stated through reaction between the aniline

• the same amine component) deprotonates the terminal alkyne, generating the metal acetylide derivative A, which is the active nucleophilic species in the reaction. Intermediate A undergoes an oxidative addition by the dihaloalkane, generating intermediate B. This undergoes reductive elimination to

Study of the interaction of 2H-furo[3,2-b]pyran-2-ones with nitrogen-containing nucleophiles

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2025, 21, 556–563, doi:10.3762/bjoc.21.44

• Constantine V. Milyutin Andrey N. Komogortsev Boris V. Lichitsky N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Pr., 47, Moscow, 119991, Russian Federation 10.3762/bjoc.21.44 Abstract For the first time, the reaction of substituted 2H-furo[3,2-b]pyran-2-ones

• with diverse N-nucleophiles was investigated. It was shown that the direction of the process depends on the type of employed nitrogen-containing reagent. For example, condensation with aliphatic amines leads to 2H-furo[3,2-b]pyran-2,7(3H)-diones bearing an exocyclic enamine moiety. At the same time

• unambiguously confirmed by X-ray diffraction. Keywords: allomaltol; enamines; 2H-furo[3,2-b]pyran-2-ones; pyrazol-3-ones; recyclization; Introduction Substituted furan-2(5H)-ones (butenolides) are widely used as precursors for the preparation of diverse types of heterocyclic compounds possessing various

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• yield decreased, possibly due to the formation of imine B, which might be favored by the dehydration effect of the molecular sieves. Conclusion In summary, a regioselective and diastereoselective vinylogous addition reaction of 4-alkenyl-5-aminopyrazoles to alkyl trifluoropyruvate has been studied

• trifluoropyruvates. Synthesis of the starting materials 3. Scope of the reaction. Reaction conditions A: 3 (0.2 mmol) and 4 (0.6 mmol) in 2 mL of toluene at 70 °C. Reaction conditions B: 3 (0.2 mmol), 4 (0.6 mmol), and SQ-1 (10 mol %) in 2 mL of toluene at 50 °C. Yields refer to isolated yields after column

Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• derivatives lack a covalent attachment handle. By making use of drug conjugates, toxic payloads such as cryptophycins can be selectively delivered to the target site. We present the synthesis of two conjugable cryptophycins with amino groups in unit B, representing potential payloads for drug conjugates

• conjugable payloads by our group. Modifications of unit B with conjugation handles are scarcely explored and mainly include the exchange of the para-methoxy group (Figure 1B). The sole exchange of the para-methoxy group of cryptophycin-52 (IC50 = 22 pM) by a hydroxy group reduces the cytotoxicity by

• of N-alkylation on the non-chlorinated unit B derivatives. Results and Discussion For the synthesis of unit B derivatives with amino groups instead of the naturally occurring methoxy group ᴅ-phenylalanine served as the fundamental substrate (Scheme 1). Nitration [23] followed by methyl ester

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• between the ANTH cores. The ANTH hexagons that appear to be overlapped (see Figure 2, bottom left) are separated by 4.154 Å and are tilted from each other by 21.6°. The columns of ANTH cores are insulated along the crystallographic b-axis by the BnF groups, which can be more clearly seen by viewing down

• -10-bis(perfluorobenzyl)anthracene were mounted in a paratone oil on glass fiber rods glued to a small copper wire. X-ray diffraction data were collected at ChemMatCARS (CARS = consortium for advanced radiation sources) sector 15-B at the Advanced Photon Source (Argonne National Laboratory). The data

• software (APEX II) was employed [38], and Bruker SHELXTL software [39] was used for structure solution, refinement, and graphics. Crystal data for 9,10-ANTH(BnF)2: C28H8F14, M = 610.34, orthorhombic, a = 11.5338(4) Å, b = 24.6701(9) Å, c = 8.0275(3) Å, α = 90°, β = 90°, γ = 90°, V = 2284.15 Å3, T = 100(2

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

• packing mode. Extra precautions were taken to shield the compounds from light during synthesis, purification, and storage. After crystallizing each bimane, a vial containing multiple crystals was selected for irradiation studies. Cl2B (B), which showed 5% presence of the [2 + 2] dimer after

• is 0(0°), indicating that the reacting double bonds are coplanar and parallel. Furthermore, the intermolecular distances between the reacting carbons are identical. The distance between two carbon double bonds in Cl2B (B) was determined to be 3.487(4) Å (Table 1). The key question is why did Cl2B

• fluorescence spectrum and η is the refractive index of the solvent. Single crystal X-ray diffraction studies Crystals of Me4B, Cl2B (A), (B), (C), and Me2B were mounted on a MiTeGen micromount with NVH immersion oil. Data were collected from a shock-cooled single crystal at 100(2) K on a Bruker Apex Kappa Duo

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

• switching properties even in an aqueous environment and are therefore promising switches in photopharmacological applications. a) Structural similarity of N-acetyl diazocine 1 with known 17βHSD3-inhibitor tetrahydrodibenzazocine (THB) [17] and parent diazocine with steroid scaffolds [18]. b) Parent

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• ). Synthesis of preQ1 and DPQ1 derivatives with electrophilic handles For the synthesis of haloalkyl- and mesyloxyalkyl-modified preQ1 and DPQ1 ligands 3a,b and 4a–e (for target structures see Scheme 1), a divergent synthetic route was sought that provided flexibility with respect to linker length and nature

• , DPQ1) and haloalkyl-modified preQ1 and DPQ1. B) The ligand classes of XcnpreQ1 and XcnDPQ1 allow specific formation of covalent small molecule–RNA complexes as has been recently demonstrated (see ref. [4]). Electrophile (E). Three-step syntheses of preQ1 (1) and DPQ1 (2). For the synthesis of m6preQ1

• ) for synthetic contributions. Funding This work was funded in part by the Austrian Science Fund FWF [P31691, F8011-B] and the Austrian Research Promotion Agency FFG [West Austrian Bio NMR 858017].

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

• catalyst or the bistrifluoromethyl-substituted analog B could enable the retro-Michael reaction of only one enantiomer of the racemic mixture, potentially leading to a kinetic resolution of the 1,5-dicarbonyl compounds (Scheme 2). Results and Discussion An initial attempt was made to determine if the retro

• without a co-catalyst but is slower, resulting in a lower enantiomeric ratio than in an acidic medium. The obtained results show that the diphenylprolinol derivative A provides a better enantiomeric ratio than that achieved with the α,α-bis[3,5-bis(trifluoromethyl)phenyl]prolinol derivative B (compare

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• : optical path. The benefits of merging photochemistry with mechanochemical setups (top). Most common setups for photomechanochemistry (bottom): a) manual grinding, b) vortex mixing, c) rod milling, and d) ball milling. SWOT (strengths, weaknesses, opportunities, threats) analysis of photomechanochemistry

• reactions: A) atom-transfer-radical addition, B) pinacol coupling, C) decarboxylative alkylation, D) [2 + 2] cycloaddition. The photo in Scheme 11 was reproduced from [77] (© 2024 F. Millward et al., published by Wiley-VCH GmbH, distributed under the terms of the Creative Commons Attribution 4.0

• International License, https://creativecommons.org/licenses/by/4.0). Use of mechanoluminescent materials as photon sources for photomechanochemistry. SAOED: SrAl2O4:Eu2+/Dy3+. A) Hofmann–Loffler–Freytag reaction; B) EDA-based photochemistry [78]. Acknowledgements L.C. acknowledges the COMP-HUB and COMP-R

Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• Br(II) followed by subsequent deprotonation to generate radical B. A following disproportionation of radical B would lead to the formation of Br(III) species C (anodic oxidation cannot be fully excluded), which undergoes intramolecular SNAr-type substitution to form cyclic λ3-bromane 1a and

• hypobromite D. The latter decomposes into bromide and hexafluoroacetone, with the latter observed by 19F NMR [25]. Assuming that intermediate B is sufficiently stable to leave the diffusion layer and undergoes disproportionation to the species C in the bulk electrolyte provides a reasonable explanation for

• -tetrafluorobenzene as an internal standard. Isolated yields are given in parentheses. A: Background and iR drop-corrected CVs of 5 mM 4a at different scan rates (solvent: HFIP, working electrode: glassy carbon, supporting electrolyte: 0.1 M TBA-BF4). B: Plot of the peak current densities (jp) vs v0.5. C

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

• concentration. As for the macrocycles discussed above, dual confinement/encapsulation [36] and the hydrophobic effect dominate the origin of catalytic rate enhancements [158][159]. To avoid product inhibition, model reactions that increase molecularity (A → B + C) or that generate weakly interacting or less

• reactivity. (B) Macrocycles with functional sites that react with bound substrates directly. (A) Cram’s serine protease model system [87][88]. The macrocycle showed strong substrate binding (organization), but the model did not show strong acceleration for a hydrolysis reaction. The “organized” catalytic

• triad (red) was hoped to activate the benzyl alcohol nucleophile, but it does not activate (polarize) the electrophile (substrate ester group). (B) One of Rebek’s “clefts” [108][109]. The rigidly organized carboxylic acids both bind the substrate and the transition state for hydrolysis of an acetal. (A

Unraveling aromaticity: the dual worlds of pyrazole, pyrazoline, and 3D carborane

• Zahra Noori,
• Miquel Solà,
• Clara Viñas,
• Francesc Teixidor and
• Jordi Poater

Beilstein J. Org. Chem. 2025, 21, 412–420, doi:10.3762/bjoc.21.29

• their broader use. With this in mind, Lee and colleagues have recently developed an efficient synthetic method for producing o-carborane-fused pyrazoles as a novel scaffold, without using transition metals. Their approach involves reacting B(4)-acylmethyl and B(3,5)-diacylmethyl o-carborane with 2-azido

• assessed using indicators such as magnetic-based NICS, electronic-based MCI, or bond lengths, among others, given its multidimensional character [41][42][43]. Results and Discussion We have first analyzed a series o-carborane-fused pyrazoles involving the fusion to either a C–C, C–B or B–B bond in the

• the carborane and the pyrazole, i.e., B–B, C–B and C–C decrease from 1.760, to 1.674 and to 1.605 Å, respectively (Figure 2). Thus, the longer the length of the fusing bond, the lower the tension of the formed five-membered ring and the more stable the complex. The stronger strength of the C–B bond

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• by the participation of the phosphate group by reverse anomeric effect. However, according to the authors, the phosphate groups acting as a neighbouring participating group forming the corresponding oxocarbenium ion intermediate 73 (path B, Scheme 13) seemed to be more plausible. Non-ester

• route for 1,2-trans glycoside synthesis. Path B designates the route for the formation of the cyclic ester as the side product which is only possible if the mechanism proceeds through the formation of an oxocarbenium intermediate 86. This has been effectively shown by Kulkarni and co-workers who used a

• demonstrated that the use of triflimide (Tf2NH) in solvents like CH2Cl2, acetonitrile or toluene at −78 °C yielded exclusively the 1,2-trans stereoselective glycoside product 105 (protocol A, Scheme 18), while the use of triflic acid (TfOH) in ether as the solvent at ambient temperature conditions (protocol B

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• properties towards CN− and Hg2+ ions and evaluation of in vitro cytotoxic activity against A431 skin cancer and H1299 lung cancer cell lines. Results and Discussion We found that boiling of equimolar amounts of benzannelated 2,3,3-trimethylindolenines 2a,b and o-chloranil (3) (method A) in dioxane leads to

• the formation of trichlorosubstituted 1,3-tropolones 7a,b as the main reaction products (Scheme 2). Heating 2a,b in acetic acid with a two-fold excess of o-chloranil (3) (method B) is accompanied by the formation of tetrachlorosubstituted 1,3-tropolones 8a,b (Scheme 2 and Supporting Information File 1

• -(indolin-2-yl)-5,6,7-trichloro-1,3-tropolones 7a,b is accompanied by dehydrochlorination of 6 upon boiling in dioxane according to method A. One of the conditions for carrying out the reaction according to method B is the use of a two-fold excess of quinone 3. Oxidation of dihydrotropolones 6 with an

Synthesis, characterization, antimicrobial, cytotoxic and carbonic anhydrase inhibition activities of multifunctional pyrazolo-1,2-benzothiazine acetamides

• Ayesha Saeed,
• Shahana Ehsan,
• Muhammad Zia-ur-Rehman,
• Erin M. Marshall,
• Sandra Loesgen,
• Abdus Saleem,
• Simone Giovannuzzi and
• Claudiu T. Supuran

Beilstein J. Org. Chem. 2025, 21, 348–357, doi:10.3762/bjoc.21.25

• concentrations used as positive controls in these experiments were kanamycin (susceptible S. aureus, 50 μg), vancomycin (methicillin and multidrug-resistant S. aureus, 25 μg), ampicillin (E. coli, 50 μg), and amphotericin B (C. albicans, 25 μg). The final concentration of the tested compounds was 125 μg/mL for

• of contrasting 1H NMR signals for monoalkylated (7a) and dialkylated (7l) derivatives, (-NH and –OH = a, a’ and -CH2- = b, b’). Full spectra are shown in Supporting Information File 1. General scheme for the synthesis of pyrazolo-1,2-benzothiazine-N-aryl/benzyl/cyclohexylacetamide. Different N-aryl

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

• Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov Institute of Organic and Physical Chemistry, 8 ul. Akad. Arbuzova, 420088 Kazan, Russian Federation 10.3762/bjoc.21.24 Abstract New representatives of dioxodihydronaphtho[2,3-b]furan-, furo[3,2-c][1]benzopyran-, furo[2,3

• -d]pyrano[4,3-b]pyran-, furo[2',3':4,5]pyrano[3,2-c]chromene-, and furo[2,3-d]pyrimidine carboxylates were obtained from the reactions of alkyl 3-bromo-3-nitroacrylates with representatives of carbo- and heterocyclic CH-acids under simple conditions, without the use of organocatalysts. The structures

• furopyran, furocoumarin [9][10], and furopyrimidine series [11][12]. It is known that the main approaches to the synthesis of naphtho[2,3-b]furan-4,9-diones are reactions of hydroxynaphthalene-1,4-dione with ethane-1,2-diol [13], chloroacetaldehyde [14], ethenyl methyl sulfone [15], or ethenyl acetate [16

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

• derivative, farinosone D (1), along with the known 2-pyridones, farinosones A (2) and B (3), and the known cyclodepsipeptides beauvericins A–C (4–6). All isolated compounds were assessed for their antimicrobial and cytotoxic activities while farinosones D (1) and A (2) were selected for biofilm inhibitory

• activity assay. Farinosone B (3) and beauvericins A–C (4–6) showed significant cytotoxic activities with IC50 values in the low micromolar to nanomolar range against several mammalian cell lines. On the other hand, farinosone A (2), which lacked potent cytotoxic effects, revealed potent antibiofilm

• anticancer properties [6]. With concerns about biofilm formation and resistance escalating in the medical field, entomopathogenic fungi have emerged as a promising source of novel bioactive compounds [5]. Our recent exploration of B. neobassiana highlighted this growing interest, affording one tetramic acid

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• organoboron substrates 31, including -B(OH)2, -Bpin, -BF3K, and -Bneo (neopentyl borate) derivatives noted as “-[B]” in Scheme 11, to produce aliphatic alcohols and phenols 32 with moderate to excellent yields. The versatility of this method is highlighted by the broad substrate scope of more than 50 examples

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

• Zi-Ying Xiao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

• used in the reaction, a direct Michael addition of the arylamine to the C=C bond of the maleimide unit and sequential elimination of carbon dioxide and tert-butoxide ion gives the intermediate B, which in turn undergoes an allylic rearrangement to afford the product 5. In this process, no extra

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

• analysis was obtained by slow evaporation of a diethyl ether/n-hexane solution, enabling its unambiguous structural determination by single-crystal X-ray diffraction (Figure 1). The planar BPP core and the isopropyloxy group on the zigzag edge are clearly visualized (Figure 1a and b). In a unit cell

• BPP-OiPr 3: a) top view, b) side view (thermal ellipsoids shown at 50% probability), and c) molecular packing of 3 in a unit cell. All the hydrogen atoms are omitted for clarity. a) UV–vis absorption spectra of BPP 2, BPP-OiPr 3, and BPP-dione 4 measured in toluene. Inset: magnified spectra of 2 and 3

• for the better visualization of the longest-wavelength peaks, b) normalized PL spectra of BPP 2, BPP-OiPr 3, and BPP-dione 4 measured in toluene with a 360 nm excitation. Inset: absolute PLQY of BPP 2 (excitation at 360 nm), BPP-OiPr 3 (excitation at 380 nm), BPP-dione 4 (excitation at 470 nm) in

Three-component reactions of conjugated dienes, CH acids and formaldehyde under diffusion mixing conditions

• Dmitry E. Shybanov,
• Maxim E. Kukushkin,
• Eugene V. Babaev,
• Nikolai V. Zyk and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 262–269, doi:10.3762/bjoc.21.18

• -4,4a,5,7a-tetrahydrocyclopenta[b]pyran-3-yl)methanone (9). From 1,3-diphenylpropane-1,3-dione (224 mg, 1.0 mmol), ʟ-proline (6 mg, 0.05 mmol) and cyclopentadiene (330 mg, 5.0 mmol), compounds 8 (136 mg, 45%) and 9 (97 mg, 32%) were obtained as white crystalline solids. Major isomer 8 1H NMR (400 MHz

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• model reaction was proposed (Scheme 6). First, 1a was acidified to form p-methylbenzenesulfinic acid A, and A was reduced by HI to form p-tolyl hypoiodothioite B, which then reacted with A to form the thiosulfonate C. 3a undergoes a cyclization reaction to form 3aa in an acidic environment. Compound B