Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• , most likely due to different crystalline packing motifs. Keywords: fluorescence; fluorinated aromatics; phenacene; photoreaction; Introduction Polycyclic aromatic hydrocarbons (PAHs) have been subject of continuous interest not only from aspects of fundamental synthetic, structural, and physical

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

• fluorescence and NMR experiments. Acknowledgements We would like to thank Prof. Wennemers for her continuous support and for providing access to the infrastructure necessary to carry out the research described herein.

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

• automated and continuous mixing during irradiation, thus increasing the reproducibility and convenience of the process [67]. In particular, the authors found that the simultaneous irradiation using a low-pressure Hg lamp and grinding led to 97% 1H NMR yield of 2.3 in 24 h starting from 2.1 and 2.2, which

• corresponds to a 4-fold improvement on reaction rates compared to manual grinding [64]. The authors proposed that continuous mechanical stress results in an increase of nucleation sites and allows catalysis to be accelerated with respect to manual grinding. Moreover, continued mechanical stress imparted by

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

• cage and the heterocycle. This latter conclusion is further supported by the computed current density maps for the o-carborane-fused pyrazoles (Figure 6). It is observed a non-continuous diatropic ring current in the five-membered ring, interrupted by the fusing bond between the cage and the pyrazole

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

• Dried acetonitrile (10 mL) was used to prepare a solution of compound 5 (251 mg, 1.0 mmol) followed by addition of anhydrous K2CO3 (173 mg, 1.25 mmol) under continuous stirring and heating. After 30 minutes, the solution of the respective 2-chloro-N-aryl/benzyl/cyclohexylacetamide 6a–h (1 mmol) in dry

• -benzothiazine-N-aryl/benzyl/cyclohexylacetamides 7i–n Dried acetonitrile (10 mL) was used to prepare a solution of compound 5 (1.0 mmol, 251 mg) followed by the addition of anhydrous K2CO3 (297 mg, 2.15 mmol) under continuous stirring and heating. After 30 minutes, the solution of respective 2-chloro-N-aryl

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

• to give 22. In a same manner, Opatz et al. have shown that zinc phthalocyanins can catalyze oxidative cyanation reactions of tertiary amines 23, yielding α-aminonitriles 24 under continuous-flow conditions [36]. This reaction proceeds through the excitation of zinc phthalocyanin by near-infrared

• in continuous-flow conditions. This performance is particularly notable given that the reaction was carried out using sub-part-per-million loadings of the catalyst (0.003 mol %), a stark contrast to traditional systems, which often require higher concentrations of heavy metals. Unlike classical

• integrity over extended reaction times, even under high substrate concentrations and continuous flow conditions, achieving high turnover numbers of over 50000. This stability allowed for solvent-free reactions, significantly enhancing the sustainability of the process. Additionally, the authors have

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

• consists of a single band at 1704 cm−1, assigned to the ν(CC)exo-CBD vibration, which moved to 1689 cm−1 in 2•+, and to 1686 cm−1 in 22+. This continuous downshift upon oxidation is in contrast to the observed upshift in 1•+ → 12+, corroborating that the fusion topology of the two molecules determines the

• were generated using the continuous set of gauge transformations (CSGT) method, as implemented in the Gaussian 09 suite, and the AICD 2.0.0 program [34]. Chemical structures of heptacene, diindenoanthracene (DIAn), and the molecules of 1 and 2 studied in this work (TIPS: triisopropylsilyl, Mes: mesityl

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

• group developed the electrocatalytic racemic C(sp³)–H alkynylation of THIQs with terminal alkynes in a continuous-flow microreactor using copper/TEMPO relay catalysis [51]. The electrocatalytic reaction in continuous flow facilitates straightforward scale-up and demonstrating a broad substrate scope. In

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

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

• categorical and continuous variables, in particular for the stoichiometry and chemical formulation of reaction mixtures. Many HTE batch experiments have been performed in self-contained automated platforms developed by various instrument manufacturers (Chemspeed, Zinsser Analytic, Mettler Toledo, Tecan

• of stereoselective Suzuki–Miyaura couplings, offering precise control over both categorical and continuous variables (Figure 2a) [15]. The integrated robotic system containing a four-needle dispense head facilitated the delivery of reagents in low volume and slurries, ensuring the accuracy and

• continuous or segmented (also known as slug). Segmented flow reactions present an efficient means to gather diverse data points by creating segmented or droplet flow within microfluidic reactors. Each droplet is carefully separated by either an antisolvent or an inert gas, thus providing every droplet with

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• of enol acetates with aryldiazonium salts [93]. The excitation of the porphyrin macrocycles by light irradiation initiated the catalytic cycle, generating aryl radicals from the diazonium salts, similar to findings by Gryko and co-workers. They explored both batch and continuous-flow photocatalysis

• using these systems, achieving improved yields of up to 92%. Notably, a multigram-scale experiment was successfully performed, producing 3.03 g of the desired product under continuous-flow conditions. In 2020, de Oliveira and co-workers published a review covering the field of metal-free porphyrin

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• involving variations in light exposure and quantum yield established the need for continuous irradiation and eliminated the possibility of a radical chain mechanism for the reaction. Recently in 2023, Yadav and colleagues demonstrated that diaryliodonium salts are effective for arylating and cyclizing

Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions

• Hayato Takagi,
• Çetin Çelik,
• Ryosuke Fukuda,
• Qi Guo,
• Tomohiro Higashino,
• Hiroshi Imahori,
• Yoko Yamakoshi and
• Tatsuya Murakami

Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231

• catC60 and PyBA from the membranes. ESR measurements for photoinduced 1O2 and O2•– generation ESR spectra were recorded on a Bruker EMX, Continuous Wave X-Band EPR spectrometer (Bruker BioSpin GmbH, Rheinstetten, Germany). Suprasil® ESR tubes with a diameter of 4 mm, length of 250 mm and a wall thickness

Transition-metal-free synthesis of arylboronates via thermal generation of aryl radicals from triarylbismuthines in air

• Yuki Yamamoto,
• Yuki Konakazawa,
• Kohsuke Fujiwara and
• Akiya Ogawa

Beilstein J. Org. Chem. 2024, 20, 2577–2584, doi:10.3762/bjoc.20.216

• contribution of this work. We acknowledged Mr. Reiya Kani (University of Yamanashi) for his experimental support. Y.Y. would like to express his deepest gratitude to Prof. Dr. Tetsuo Kuwabara (University of Yamanashi) for his insightful feedback and continuous mentorship that significantly contributed to the

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• oxidants or reductants, offer unprecedented control of reactions through the continuous variation of the applied potential and the possibility of combination with photochemical processes. This capability is a substantial advantage for performing electrochemical or photoelectrochemical LSF. Ultimately

• reactors for industrial applications. The potential for upscaling and applicability towards LSF makes electrosynthesis particularly appealing for the fine-chemical and pharmaceutical industry. As the electrode potential can be fine-tuned over a continuous scale, higher functional group compatibility can be

• . Additionally, the increased interest of medicinal chemists in electrochemical methods, combined with their continuous search for new LSF strategies, will further extend the applicability of newly established electrochemical methods. LSF is a rapidly growing field that offers new opportunities in drug discovery

Visible-light-mediated flow protocol for Achmatowicz rearrangement

• Joachyutharayalu Oja,
• Sanjeev Kumar and
• Srihari Pabbaraja

Beilstein J. Org. Chem. 2024, 20, 2493–2499, doi:10.3762/bjoc.20.213

• challenges. To address these points, a novel continuous photo-flow platform for the Achmatowicz reaction including integrated post-synthetic work-up in a safe and faster manner with less intervention of human was developed (Scheme 1 (2)). This process involves a nature abundant energy source such as sun

• reaction selectivity [25]. Continuous flow technology has emerged as an attractive solution for many of these challenges, gaining popularity for its ability to efficiently address these issues. Additionally, this platform offers the advantage of integrating multiple steps, i.e., performing multistep

• -off experiment was performed to examine the Achmatowicz rearrangement's dependence on light, and it was observed that continuous light irradiation was required (Table 1, entry 2). Next, we considered running the process without utilizing the Ru(bpy)3Cl2·6H2O catalyst (Table 1, entry 3). There was no

Machine learning-guided strategies for reaction conditions design and optimization

• Lung-Yi Chen and
• Yi-Pei Li

Beilstein J. Org. Chem. 2024, 20, 2476–2492, doi:10.3762/bjoc.20.212

• acid–base salts, and continuous variables, such as temperature, pressure, substrate concentration, and residence time. Regression prediction models are then built for these reaction parameters and target objectives by collecting experimental data and conducting statistical analysis. Many reaction

• algorithm for the shell growth of core-shell semiconductor nanoparticles. This involves various unit operations such as phase separation, washing, and continuous in-situ spectral monitoring. Although the process conditions for this reaction system do not have as extensive a literature base for training data

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• its control difficult and risky. In this paper, a homogeneous continuous flow microreactor system was developed for the nitration of O-methylisouronium sulfate under high concentrations of mixed acids, with a homemade static mixer eliminating the mass transfer resistance. In addition, the kinetic

• 94%, initial reactant concentration of 0.5 mol/L, reaction temperature of 40 °C, molar ratio of reactants at 4.4:1, and a residence time of 12.36 minutes. Keywords: continuous flow; kinetic modeling; nitration; reaction optimization; static mixer; Introduction The demand for high-quality

• reaction process of O-methylisouronium sulfate to improve the reaction efficiency and intrinsic safety. In recent years, continuous flow microreactors have been recognized due to their excellent mass and heat transfer performance, precise control over reaction parameters, and intrinsic safety [5][6][7][8

Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• dithioacetals and nitroethane/amines [72][73]. As part of our continuous research in this context, more recently we investigated the selective hydrolysis of α-oxo ketene N,S-acetals in water to gain an environmentally compliant synthetic method for β-keto thioesters and β-keto amides (Scheme 1c). Herein, we

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• the conjugate addition of propanal (22) and trans-β-nitrostyrene (11) catalysed by a simple solid-supported peptidic catalyst 24 using a continuous flow reactor. To overcome the diffusion limitations, elevated pressure was applied. Increasing the pressure from atmospheric to 60 bar resulted in a 12

• mesoporous material. Photoinduced RAFT polymerisation of n-butyl acrylate (19) catalysed by silica nanoparticle-supported eosin Y 21, which could be recycled over five reaction cycles. Pressure and temperature dependence of the 1,4-addition of propanal to trans-β-nitrostyrene under continuous flow conditions

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• solution and in the solid state [127]. Furthermore, even sugar-functionalized pyrazoles have been accessed by this approach [128], and it was readily implemented in a continuous flow reactor [129]. Besides traditional Sonogashira catalyst systems, highly reactive and reusable immobilized Pd-complexes, such

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• , Alcazar et al. developed continuous flow protocols for both the generation of alkylzinc halides and for the subsequent Negishi cross-coupling reaction [40][41][42][43][44]. We successfully adapted Alcazar’s protocols for the synthesis of otherwise challenging heteroaryl–alkyl connections (see Table S1 in

• with the Negishi cross-coupling step in a continuous flow manner [41][42][43]. Continuous flow chemistry offers superior control over reaction parameters compared to traditional batch methods. This approach leads to reproducible reactions, improved safety features, and it can facilitate high-throughput

• screening and rapid optimization [46][47]. Homogenous heating and mixing in flow reactors can lead to higher reaction rates and yields. In terms of photochemistry, continuous flow setups provide enhanced light irradiation as well [48][49]. These advantages make flow chemistry a powerful tool for chemical

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• , albeit with a slow but continuous deterioration of catalytic activity. Preliminary molecular docking and molecular dynamics simulation studies revealed that Thr40 and Ser105 residues played a crucial role in catalyzing the GBB reaction, forming hydrogen bonds with 2-aminopyridine substrate, increasing

Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

• Hiwot M. Tiruye,
• Solon Economopoulos and
• Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153