Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• aqueous media is limited (Figure 1a–c) [13][14][15][16][17][18]. In particular, receptors which bind tryptophan residues in peptides are rare [19][20]. Recently, we developed a glucose-based naphtho crown ether 1 (Figure 1d) which binds amino acid methyl esters with aromatic side chains chemoselectively

• tripeptides 2–7 consisting of one tryptophan and two alanine residues. We varied the position of the tryptophan in the peptide sequence, N-terminus in 2, middle of the chain in 3, and C-terminus in 4 to check if this affects their binding by 1. To probe the importance of the N-terminal amino group in the

• , they open exciting opportunities for the development of other monosaccharide-based selective receptors of amino acids in aqueous environments. a–c) Examples of synthetic receptors for selective binding of tryptophan in aqueous media, taken from refs. [14][15][16]; d) glucose-based naphtho crown ether 1

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

• -phenyl position of unit A [9][10][11] or derivatisation of unit A’s epoxide moiety into a halohydrin (-glycinate) [5][12][13][14][15][16][17]. Cryptophycins modified at the α-position of unit C [18] and, most recently, various derivatives with modifications in unit D [19] were established as potent and

• formation and N-Boc-protection [24] provided nitroarene 5 in 40% yield over three steps. Reduction of the nitro group was performed with Pd/C and hydrogen to obtain aniline 6 in 98% yield, which served as a precursor for mono- and dimethylated unit B derivatives 7 and 8, respectively. While dimethylaniline

• control of equivalents and pH, or Leuckart–Wallach-like reaction with ammonium formate and Pd/C [25] provided monomethylaniline 7 in 37% and 35% yield, respectively. The absolute structure of monomethylaniline 7 was confirmed by single-crystal X-ray diffraction measurements (Figure 2). Compound 7

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

• other, yet to be identified, ANTH(BnF)n compounds were also observed. In this reaction, ANTH dissolved in DMSO was heated to between 120 °C and 160 °C in the presence of 2 equiv of BnFI and 3 equiv of Cu powder as promotor for 24 h, resulting in the complete conversion of ANTH to reaction products. When

• higher selectivity with milder reaction temperatures. The weaker C(sp2)–Br bond is easier to cleave than a C(sp2)–H bond, resulting in a higher likelihood of radical substitution at those positions. To the best of our knowledge, there are no previous examples of perfluorobenzyl substitution of any PAH(Br

• used for the perfluorobenzylation of PERY were used [22]. 9,10-ANTH(Br)2 and BnFI were dissolved and heated to 160 °C in PhCN in the presence of either Cu powder (22 h) or Na2S2O3 (4 h). According to the 1H NMR spectra of the filtered product mixtures, the reaction with Cu showed poor conversion, but

Synthesis of the aggregation pheromone of Tribolium castaneum

• Biyu An,
• Xueyang Wang,
• Ao Jiao,
• Qinghua Bian and
• Jiangchun Zhong

Beilstein J. Org. Chem. 2025, 21, 510–514, doi:10.3762/bjoc.21.38

• , Mori and Phillips achieved the complete separation of the derivatives from the four stereoisomers by reversed-phase HPLC at −54 °C, and revealed that the natural pheromone consists of four stereoisomers of 4,8-dimethyldecanal (Figure 1) [16][17]. Previous syntheses mainly focused on chiral sources of

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

• crystallography, was irradiated, resulting in Cl2B (C), which showed approximately 18% dimer formation, while no dimerization was observed in the Me2B and Me4B (C) samples (see experimental section for details). The initial presence of the [2 + 2] dimer in the Cl2B (A) sample can be attributed to improper

• and is therefore not expected to undergo this topochemical reaction (Figure 6b). Examination of the reported structure of 9,10-dioxa-syn(carboethoxy,methyl)bimane in the CCDC database (BESGAH) [19][21], shows that it crystallizes in the monoclinic (P2(1)/c space group, unlike Me2B which crystallizes

• groups play a role by increasing the number of hydrogen bonds (C–H···O, 3.18(5)–3.62(6) Å) The intermolecular distances between the C–H groups and the chlorine atoms in Cl2B (A) are C13A–H13···Cl1A, 3.69(5), and C18A–H18C···Cl2A, 3.69(3) Å, indicating further molecular attraction [22]. A previously

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

• biochemical reactions usually take place in aqueous environments [13]. The substitution of one CH2 group in the CH2CH2 bridge by N–C(=O)–CH3 leads to an intrinsic water solubility of the N-acetyl diazocine 1 (Figure 1) [3]. Furthermore the photoconversion of 1 shows no significant drop in pure water in

• amination is a versatile and powerful tool for C–N bond formation and widely applied in the synthesis of new pharmaceutical substances [29][30][31]. Furthermore, azobenzenes [32][33], as well as diazocines [34][35], have been derivatized via Buchwald–Hartwig amination. The Buchwald–Hartwig amination of

• particular to gain insight into the effects of different substituents on UV spectra and switching behavior. For the determination of the n–π*-absorption maxima of the E and Z isomers 250 µM solutions of each compound in acetonitrile were prepared and measured at 25 °C. All compounds (4, 7–14, 17, 19–21, 23

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

• methanol (1.3 mL). Anhydrous magnesium sulfate (340 mg, 2.82 mmol, 10 equiv) and the respective amino alcohol (2.82 mmol, 10 equiv) were added. The mixture was sonicated for 30 minutes and subsequently stirred at room temperature for 16 h. After cooling to 0 °C, sodium borohydride (96.1 mg, 2.54 mmol, 9

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

• additive (entries 10–13, Table 2), but none of the tests performed led to an improvement in enantioselectivity. We also studied the influence of the reaction temperature by performing two tests at 0 °C (entries 15 and 16, Table 2). We observed that the reaction occurs more slowly, and the enantiomeric

• excess reached is lower than at room temperature. Additionally, when the reaction mixture was stirred at −18 °C, no change was observed after 100 hours (entry 14, Table 2). These results led us to raise the reaction temperature to 31 °C (entries 17–20, Table 2). We observed that the retro-Michael

• reaction occurs more rapidly than at 20 °C (entry 2, Table 2). However, the enantiomeric ratio decreases as the reaction time increases. Based on these results, we considered conducting tests to monitor how the percentage of ReM and enantiomeric ratio change over time (Table 3). With this aim, a 0.028 M

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

• alignment within the crystal drives the reaction. For example, in 2008, Vittal et al. [62] designed a mechanochemical strategy to align the C=C bonds of 4,4'-bipyridylethylene (bpe, 1.1) molecules to drive efficient [2 + 2] cycloaddition and give the corresponding cyclobutanes (1.2). This approach relied on

• spectroscopy (Scheme 1). During the reaction progress, the C=C bonds of bpe ligands undergo pedal-like motion prior to photodimerization [63]. For the single-crystal irradiation, the slow reactivity can be attributed to the hindered pedal motion in the single crystals, likely due to the presence of

• Na2CO3 was ground in a mortar at room temperature for 3–5 min. Second, the reaction mixture was transferred into a quartz tube, heated to 50 °C (heating mantle) for 18 h, while being irradiated with blue LEDs under air-equilibrated conditions. In these conditions, product 3.3 was isolated in excellent

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

• optimized reaction conditions in hand, next, the substrate scope was evaluated (Scheme 2). Symmetrical biaryls with electron-deficient substituents such as Cl (4b) or CF3 (4c) afforded the respective Br(III) products 1b,c in slightly reduced yields as compared to that of 1a. Gratifyingly, electron-rich MeO

• -substituted 1d could be also obtained under the developed conditions. Unsymmetrically substituted 4e and monosubstituted dibromides 4f,g demonstrated reactivity similar to that of their symmetrical analogues 4b,c with exception of the mono-MeO-substituted dibromide 4h. Notably, the presence of two stabilizing

• 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

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

• versions. Recent advances using hexameric resorcin[4]arene-based capsules [122][123][124] (Figure 4B and C), notably by Tiefenbacher [105][125][126][127][128][129][130][131][132][133], have demonstrated substrate-controlled selectivities that vary from the bulk phase due to the stabilization of cations in

• 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

• ]. Lattices can also contain defects, which may affect catalytic activity unpredictably [228]. Nonetheless, macroscale structures, like those that arise from the stacking in 2D COFs, can contribute to catalysis, for instance dense arrays of aligned C–H bonds can provide CH–π interactions in Diels–Alder

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

• a π system with 6 π electrons [11]. When fused with a benzene ring, sharing a C–C bond, it remains aromatic, which is the case of indazole. Pyrazoline (C3H6N2), similar to pyrazole, formally has only one double bond and a lone pair on the nitrogen, so it does not satisfy Hückel's rule and it is

• therefore non-aromatic. Even when fused with benzene via a C–C bond, pyrazoline remains non-aromatic, which is the case of indazoline. Icosahedral carboranes are globular molecular clusters made of carbon and boron, displaying 3D aromaticity [12][13][14][15]. Their unique properties – such as aromaticity

• -1,3-dimethylimidazolinium hexafluorophosphate (ADMP) in the presence of DBU in acetonitrile. This one-pot process enables sequential diazotization and cyclization, leading to the formation of two or three C–N bonds under extremely mild conditions, with excellent tolerance for various functional groups

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

• glycochemists. The protecting building blocks on the glycosides contribute significantly in attaining the required stereochemistry of the resulting glycosides. Strategic installation of suitable protecting groups in the C-2 position, vicinal to the anomeric carbon, renders neighbouring group participation

• , whereas protecting groups in the distal C-3, C-4, and C-6 positions are often claimed to exhibit remote group participation with the anomeric carbon. Neighbouring group participation and remote group participation are being widely studied to help the glycochemists design the synthetic protocols for

• referred to as α-glycosides are mostly also termed as 1,2-cis glycosides (except in the case of glycosides such as ᴅ-altrose, ᴅ-mannose, ᴅ-iodose, and ᴅ-talose with axial C-2 position), while the equatorial or β-glycosides are termed as 1,2-trans-glycosides with the glycosides mentioned above as exceptions

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

• spectrum of 7a, a correlation of the NH proton with the bridging carbon atoms C(3a'), C(9b'), and the quaternary carbon atom C(1') of the indolenine fragment is observed with δH 136.6 ppm, 134.0 ppm, and 53.6 ppm, respectively (Supporting Information File 2, Figure S20). The most important HMBC

• )-5,6,7-trichloro-1,3-tropolone [5] (dashed lines) at the positions of N(1), C(2) and C(9) atoms (hydrogen atoms removed) (Figure 4). While maintaining the general configuration of the molecular framework, there are minor differences in the details of their structures, manifested in the observed distances

• between the atoms C12)···C(13A) = 0.31 Å, Cl(2)···Cl(2A) = 0.76 Å and in the geometric parameters of the tropolone rings. The angle between the planes C(2)C(3)C(6)C(7) and C(1)C(2)C(7) is equal to 42.9° (42.1°) (here and below, when comparing geometric values, similar values are given in parentheses for

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

• to weak antimicrobial efficiency against E. coli, and C. albicans (see Figure S43 in Supporting Information File 1). These experiments showed that compounds 7b and 7h have potential antistaphylococcal activity. Microbroth dilution assays [52] were performed for the determination of MIC (minimum

• . Yellow-colored precipitates of product 5 were formed which were separated via filtration followed by washing with excess of water. After drying, recrystallization was done with ethanol. Mp 265–266 °C; yield: 221 mg (88%). Synthesis of pyrazolo-1,2-benzothiazine-N-aryl/benzyl/cyclohexylacetamides 7a–h

• 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

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

• reactions of 4-hydroxy-7-methyl-2H,5H-pyrano[4,3-b]pyran-2,5-dione and 4-hydroxy-2H,5H-pyrano[3,2-c]chromene-2,5-dione with ethynylbenzene [26] (Scheme 3). The possibility of the formation of substituted furan structures is shown by the example of the reaction of nitroalkenes with aliphatic CH acids [27

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

• spectrum to two sp3 carbon atoms at δC 67.8 (C-2') and 72.6 (C-3'), respectively. These results suggested that compound 1 possesses a tetramic acid moiety similar to prototenellin D (Figure 1), a precursor in the biosynthesis of tenellin [10], a 2-pyridone derivative purified from the entomopathogenic

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

• , thereupon highlighting potential for broad applications in photoredox catalysis on an industrial scale. In this context, T. Rovis et al. have studied a C–N cross-coupling Buchwald–Hartwig-like reaction using dual nickel and osmium catalysis under red-light activation, addressing common challenges such as

• study, the authors have developed a complementary ground-state- and excited-state-driven aryl oxidative addition platform based on an N,C,N-bismuthinidene complex, showing the unique capacity of this main-group element to engage in reactivity typically associated with d-block metals [21]. The study

• explores how this bismuth(I) complex undergoes oxidative addition with a variety of aryl electrophiles, including diazonium salts, iodonium salts, and challenging aryl iodides and aryl thianthrenium salts, typically requiring transition-metal catalysts (Figure 3). The reactivity of the N,C,N-bismuthinidene

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

• have made them to become valuable building blocks in organic synthesis. Nucleophilic additions or spiroannulation of the highly reactive carbonyl group at the C-3 position of isatins have various fascinating applications in organic synthesis, which allowed transformation of isatins into various

• spectroscopy techniques. In order to show the universality of the substitution reaction, MBH maleimides of isatins 4 were also employed in the reaction. In the absence of any base as promoter, the reaction of MBH maleimides of isatins with various aromatic amines in toluene at 65 °C gave the expected

• Figure 1 and Figure 2, it can be found that the C=C bond is located in the unit of the pyrrolidine-2,5-dione, while the scaffold of indolin-2-one is connected via a C–C single bond with the unit of the pyrrolidine-2,5-dione. Therefore, an allyl rearrangement must proceed in the reaction process, which is

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• and antiaromatic cores. Conversely, the difference of the k[ν(CC)] for the adjacent CC bonds of NAP (i.e., d–c bonds), namely 7.99–5.47 mdyn/Å in m-1 increase compared to 7.53–6.65 mdyn/Å for individual NAP which is compatible with an enhancement of the quinoid character of NAP. The k[ν(CC)] values

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

• 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

• toluene, and BPP-t-Bu (excitation at 360 nm) [22], c) normalized PL spectra of BPP-OiPr 3 measured in hexane, toluene, tetrahydrofuran (THF), dichloromethane (CH2Cl2), and DMF, and d) normalized PL spectra of BPP-dione 4 measured in toluene, THF, CH2Cl2, and DMF. SEM images of BPP-OiPr showing: a) the

• 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

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

• participation of the C=C bond. Apparently, the ratio of the adducts of the Diels–Alder (i.e., I) and the hetero-Diels–Alder reaction (i.e., II) was strongly influenced by steric factors; a decreased steric hindrance in the initial CH acid derivatives led to a more selective formation of the structures I. This

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

• disulfides from sodium sulfinate without the use of additional redox reagents remains a challenging task. 3-Sulfenylchromones are an important class of heterocyclic compounds with unique skeletons in nature that play an essential role in drug synthesis and development. To synthesize these compounds, direct C

• reaction temperature resulted in a significant decrease in the yield (Table 1, entry 16) and at 80 °C no desired product, but only thiosulfonate was formed (Table 1, entry 17). The reaction did not proceed in the absence of acid or catalyst (Table 1, entries 18 and 19). Compared to TBAI, other iodized

• reaction at 120 °C for 2 hours were determined as optimal conditions for the reaction (Table 1, entry 14). Under the optimized conditions, the coupling reaction of various sodium arylsulfinates was investigated to assess the scope and generality of this protocol. The results, shown in Scheme 2

Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory

• Misato Suganuma,
• Daichi Kitagawa,
• Shota Hamatani and
• Seiya Kobatake

Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16

• the visible region for all molecules, in which a visible absorption maximum was observed at 487, 467, 447, 454, and 440 nm for N3(c), N4(c), and I1(c)–I3(c). Note that the λmax of I4(c) could not be determined due to the overlapping absorption bands of the open-ring and closed-ring isomers. The

• absorption band in the visible region disappeared and returned to the initial one by stopping UV light irradiation. These results indicate that all molecules exhibit T-type photochromic reactions based on 6π aza-electrocyclic reaction. The absorption bands of compounds I1(c)–I4(c) are blue-shifted compared

• to N1(c)–N4(c), which is due to the localization of the π conjugation in the central part of the molecular skeleton as reported in inverse-type diarylethenes [64]. Figure 1c and the video (Supporting Information File 2) show the photochromic behavior of N4 at room temperature in n-hexane. It was

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• . Furthermore, terminal olefins with varying chain lengths also reacted successfully, resulting in 5-membered and 7-membered cyclized products (3l–p) with yields between 44% and 66%. The lower yields in these cases might be due to the low reactivity of the intermediate C (Scheme 3), which may have made it less

• exchange between PIDA and CF2HCOOH would generate PhI(OCOCF2H)2 A. Homolysis of A under visible light (72 W white light) produced an iodanyl radical B and a CF2H radical. The CF2H radical regioselectively added to 1a to form intermediate C. Subsequently, intermediate C could be converted into the radical