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

• 3aa–ca in good yields (47–69%). On the other hand, the reaction with tetrahydro-4H-pyran-4-one (1d) occurred with a significant decrease in yield, dropping to 11%. The yield is also affected by the number of carbon atoms of the starting cyclic ketone 1. In the case of structure 3ea, which involves 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

• reacts with hydrazine hydrate and is heated to reflux, forming a pyrazolinone 2. This product is then chlorinated at the α-carbon, introducing a leaving group, to yield 3. The parent pyrazolinone 3 is subsequently treated with a base (either K2CO3 or N,N-diisopropylethylamine) to form the bimane 4. For

• 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

• refined isotropic on calculated positions using a riding model with their Uiso values constrained to 1.5 times the Ueq of their pivot atoms for terminal sp3 carbon atoms and 1.2 times for all other carbon atoms. Disordered moieties were refined using bond length restraints and displacement parameter

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

• provided the corresponding amino-substituted N-acetyl diazocine 21 (Scheme 1). Another option for carbon–heteroatom bond formation reactions are copper-catalyzed Ullmann-type reactions, which have already been applied to the parent diazocine [36][37]. The attempted synthesis of azide-functionalized N

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

• organometallic catalysis [15], enzymatic catalysis [16], aminocatalysis [17][18][19], and hydrogen-bonding catalysis [20][21][22]. The Michael addition reaction is a versatile synthetic methodology that allows the formation of new carbon–carbon and carbon–heteroatom bonds through the coupling of electron-poor

• recorded in CDCl3 or acetone-d6. Chemical shifts for protons are reported in ppm from tetramethylsilane as an internal reference. Chemical shifts for carbons are reported in ppm from tetramethylsilane and referenced to the solvent's carbon resonance. Specific rotations were measured using a 5 mL cell with

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

• yield of 79%. Scanning electron microscopy (SEM) analysis revealed the deformation and reduction in size of SAOED particles upon milling. Interestingly, carbon determination experiments revealed that SAOED is quickly poisoned by organic matter, thus hampering recyclability. This can be to some extent

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

• -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

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

• 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

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

• the inversion at the anomeric sp3 carbon centre by the attack of the acceptor moiety. Crich β-mannosylations are classic illustrations for the same [38][39]. On the other hand, the stability of the carbocation contributes towards the reaction to proceed via the dissociative two-step SN1 reaction

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

• , no correlations of the down-field proton with the carbon atoms of the indolenine fragment are observed (Supporting Information File 2, Figures S21 and S22). Thus, in CDCl3, compound 7a is predominantly in the (OH) tautomeric form. The structure of 2-(3,3-dimethyl-3H-benzo[g]indolin-2-yl)-5,6,7

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

• methylene at 67.7–68.0 ppm, one N-methyl at 38.1–38.2 ppm, and one carbonyl carbon signal at 166.5–167.6 ppm. Also for compounds 7i–n, distinct 13C NMR chemical shifts were observed: two methylene carbon resonances at 54.7–68.2 ppm, one N-methyl at 37.9–38.0 ppm, and two carbonyl carbon signals at 165.2

• –166.7 ppm. Aromatic carbon chemical shifts for both sets of derivatives 7a–h and 7i–n were found in the range of 109.1–156.0 ppm. In vitro antimicrobial and SAR analysis Microbroth single dose antimicrobial assays were performed against different pathogens including susceptible Staphylococcus aureus

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

• 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

• ketocarbonyl carbon at δC 192.9 (C-1') confirming the presence of a hydroxy group at C-3' and to be as depicted in Figure 1. Further key HMBC correlations were recognized including those from an olefinic proton at δH 5.51 (d, J = 9.6 Hz, H-11) to one allylic methyl group at δH 1.77 (d, J = 1.2 Hz, H3-16) and

• one doublet methyl group at δH 0.94 (d, J = 6.6 Hz, H3-15) indicating its presence in the middle between both methyl groups. The latter together with a terminal triplet methyl group at δH 0.80 (t, J = 7.4 Hz, H3-14) further revealed key correlation to one tertiary and one secondary sp3 carbon atoms at

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

• the substrate, an activated ester 25, subsequently generating carbon-centered radicals without the need for sacrificial electron donors via a decarboxylation process. In reacting with electron-deficient alkenes or alkynes 26, these radicals further yield tetralin and dialin moieties 27, respectively

• , and heptamethin derivatives. The length of the polymethin chain has a pronounced effect on their absorption properties, with the addition of each conjugated carbon–carbon double bond causing a red shift of about 100 nm in the absorption spectrum. The formation of J-aggregates allows cyanin compounds

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

• derivatives. At first, a Lewis base attack at the α-position of the MBH nitrile of isatin resulted in the intermediate A with elimination of carbon dioxide and tert-butoxide ion. Secondly, the product 3 was produced by the SN2 substitution of the Lewis base by the arylamine. When MBH maleimides of isatin were

• 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

• addition of Lewis base is needed. When triphenylphosphine or tri(n-butyl)phosphine were involved in the reaction, the similar SN2’ substitution of tri(n-butyl)phosphine with the elimination of carbon dioxide and tert-butoxide anion gives the phosphonium salt C. Then, the deprotonation of phosphonium salt C

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

• Electrochemistry Cyclic voltammetry experiments were conducted with a three-electrode geometry operating with a glassy carbon as the working electrode. A Pt-coil counter electrode. and an Ag wire, as the pseudo-reference, were used. Potential values are given with respect to the ferrocene/ferrocenium (Fc/Fc

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

• Islam S. Marae Jingyun Tan Rengo Yoshioka Zakaria Ziadi Eugene Khaskin Serhii Vasylevskyi Ryota Kabe Xiushang Xu Akimitsu Narita Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan

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

• Zhenlei Zhang Ying Wang Xingxing Pan Manqi Zhang Wei Zhao Meng Li Hao Zhang School of Chemistry and Material Engineering, Anhui Provincial Key Laboratory of Green Carbon Chemistry, Engineering Research Center of Biomass Conversion and Pollution Prevention of Anhui Educational Institutions, Biomass

• prevented their widespread use on a large scale. Recently, research efforts have focused on exploring alternative reagents that offer the advantages of being odorless and more stable than thiols. These alternatives include sulfonyl chloride [26], sulfonyl hydrazine [27], carbon disulfide [28], and sodium

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

• generated and followed using the keyword Guess (mix, always). The frequency calculation for the TS was carried out to confirm that there is only one imaginary frequency corresponding to the stretching vibration between the nitrogen and the carbon atoms at the reactive site. The frequency calculation for

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• expected to facilitate the 6-endo-dig cyclization to the distant sp-carbon on the alkyne, as demonstrated by Fujii and Ohno in their total synthesis of (−)-quinocarcin [52][53]. Secondly, the 6-endo-cyclized product 12, bearing the furan-conjugated isoquinoline-type framework, is predicted to be

• Strecker reaction and cyclization to form the 2,3-diaminobenzofuran moiety, and gold(I)-promoted cascade sequence via 6-endo hydroamination, spontaneous dehydrogenative oxidation followed by ring opening. Carbon numbering was assigned in accordance with natural products. The structure of 16 was determined

Heteroannulations of cyanoacetamide-based MCR scaffolds utilizing formamide

• Marios Zingiridis,
• Danae Papachristodoulou,
• Despoina Menegaki,
• Konstantinos G. Froudas and
• Constantinos G. Neochoritis

Beilstein J. Org. Chem. 2025, 21, 217–225, doi:10.3762/bjoc.21.13

• Marios Zingiridis Danae Papachristodoulou Despoina Menegaki Konstantinos G. Froudas Constantinos G. Neochoritis Department of Chemistry, University of Crete, Voutes, 71003 Heraklion, Greece 10.3762/bjoc.21.13 Abstract C1 chemistry has a central role in the efficient utilization of single-carbon

• structure was obtained, revealing certain geometrical features. Keywords: 2-amino-substituted heterocycles; cyanoacetamide; Gewald reaction; multicomponent reaction (MCR); pyrimidine; Introduction The term “net-zero carbon” is becoming increasingly common as we consider a future marked by a rising global

• temperature and severe weather patterns – a result of human-induced greenhouse gas emissions. The principle of net-zero revolves around the idea of using Earth’s carbon resources at a rate that does not exceed their natural replenishment. In 2015, the United Nations introduced the Sustainable Development

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• iridium (Scheme 1b) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Notably, dioxazolones have primarily been studied in directed carbon–hydrogen amidation processes, which can circumvent the need for tedious prefunctionalizations. Copper catalysts have gained recognition and attracted

• enantioselectivity. Furthermore, a lactam containing a quaternary carbon center (2g) was prepared. However, a lower enantioselectivity was observed for product 2h due to the similar steric environment of the two alkyl substituents. As shown in Figure 1, a catalytic cycle was proposed for the intramolecular C–H

• ) chloride reacts with boronic acids, forming the copper aryl complex INT-16, which then undergoes decarboxylative N–O bond insertion to generate the copper nitrenoid intermediate INT-17. Thereafter, nitrene insertion into the copper–carbon bond occurs, forming a new C(sp2)–N bond (INT-18). Finally, the

Quantifying the ability of the CF₂H group as a hydrogen bond donor

• Matthew E. Paolella,
• Daniel S. Honeycutt,
• Bradley M. Lipka,
• Jacob M. Goldberg and
• Fang Wang

Beilstein J. Org. Chem. 2025, 21, 189–199, doi:10.3762/bjoc.21.11

• oxygen, nitrogen, or sulfur, and a positively charged hydrogen atom, which interacts with a lone pair on the acceptor. Apart from these common heteroatom-containing hydrogen bond donors, certain carbon–hydrogen moieties can also act in this way, although in a substantially weaker capacity [5][6][7][8][9

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• electrochemistry and copper catalysis for various organic transformations. Keywords: copper; electrochemistry; radical chemistry; single-electron transfer; sustainable catalysis; Introduction Transition-metal-catalyzed cross-coupling has emerged as an effective method for forming carbon–carbon (C–C) and carbon

• enantioselective radical cyanation. In the proposed catalytic cycle, Co(III)–H species 92 are initially formed from the anodically oxidized Co(III) complex 91 and hydrosilane 88 (Figure 15). Subsequently, the HAT between the Co(III)–H catalyst 92 and the alkene 27 generates a carbon-centered radical species 93

• radical, which adds to the alkene 97 to form carbon-centered radical intermediate 106 (Figure 17). The resulting alkyl radical intermediate 106 then reacts with the Cu(II)(CN)2 catalyst 109 to produce a Cu(III) species 107, which undergoes reductive elimination to deliver the desired product 105 and the

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C–F bond activation

• Takeshi Fujita,
• Haruna Yabuki,
• Ryutaro Morioka,
• Kohei Fuchibe and
• Junji Ichikawa

Beilstein J. Org. Chem. 2025, 21, 146–154, doi:10.3762/bjoc.21.8

• coupling reactions of aromatic C–F and C–Br bonds with arylboronic acids. Keywords: arylboronic acid; benzofuran; C–F bond activation; cross-coupling; nickel; Introduction The metal-catalyzed activation of aromatic carbon–fluorine (C–F) bonds is widely recognized as a challenging task in synthetic

• -deficient carbon atom owing to the nearby fluorine and oxygen atoms. We expected that 2-fluorobenzofurans 1 could form nickelacyclopropanes E upon treatment with zero-valent nickel species. Subsequent β-fluorine elimination from these intermediates E would facilitate the activation of aromatic C–F bonds

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• to multiple C–C bonds generates extended carbon radicals capable of giving further functionalization. Regarding the ionic mechanism, the key step generally comprises the complexation with the unsaturated substrate leading to activation of the alkenyl/alkynyl moiety towards a nucleophilic attack. In

• orientation between the electron-rich nitrogen of the diene and the electron-poor carbon of the alkyne. A different one-pot procedure affording tetrahydropyridines was developed employing two molecules of aromatic aldehydes, ethyl acetoacetate and two molecules of aniline. The copper triflate catalyst acts in

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• different conditions. This parallel reactor setup was successfully utilized for the multistep synthesis of 18 compounds of an anticonvulsant drug, employing various reaction pathways to perform photoredox carbon–nitrogen cross-coupling reactions. A parallel droplet flow system was developed by Eyke et al