Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

• Daniel Krappmann and
• Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

• synthesized (Scheme 1, bottom). In contrast to the previously synthesized large library carbon-based NBDs [40], only a few heterocyclic derivatives were successfully isolated. During the monitoring of additional reactions attempting to reproduce the literature scope, in most cases traces of new NBD species

• -containing push–pull derivative that could be synthesized in rather high quantity and purity. Monitoring first the switching process from O-NBD2 to O-QC2 by UV–vis spectroscopy showed complete formation of O-QC2 was achieved after 5 seconds, indicated by the major decrease of the NBD signal at λmax = 392 nm

• observed π–π* absorption from λπ–π* = 294 nm to 298 nm was found. Prolonged irradiation up to 660 s led to a complete change in the overall absorption properties with maxima at λ = 348 nm and 297 nm and an absorption shoulder at λ = 228 nm suggesting photodecomposition. Next, NMR monitoring of the

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• fluorescent protein (GFP), has revolutionized genetics by providing highly accurate real-time detection of fusion proteins in vitro and in vivo [1]. Pioneering work on GFP-tagged proteins for real-time monitoring of gene expression was first reported by Chalfie and co-workers in 1994 [2]. For a long time

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

• (C8F17)2 [36]. These results make it clear that monitoring photoirradiated solutions by UV–vis spectroscopy must be accompanied by complementary analyses to enable accurate interpretation of the changes in the UV–vis spectra and identification of the photoproducts. The next comparative photostability

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

• was then taken at time intervals of 15–30 minutes for a total of 3 h. The UV–vis monitoring revealed that the absorbance decreases as irradiation continues, indicating photodegradation; however, no evidence of a [2 + 2] cycloaddition product was seen in the spectra (Supporting Information File 1

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

• all synthesized compounds. Thermal half-lives (t1/2) were determined by monitoring the thermal relaxation of the synthesized diazocines at 25 °C in a UV spectrometer (see Supporting Information File 1, section III). The dihalogenated N-acetyl diazocine 4 shows a significantly reduced half-life

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

• . Solvent screening for the kinetic resolution of rac-1. Screening of catalyst and co-catalyst for kinetic resolution. Monitoring the kinetic resolution of 1 over time. Study of the concentration's effect on kinetic resolution. Substrate the scope of kinetic resolution reactions. Study of the kinetic

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

• technique for high-throughput experimentation [83]. A further area of development would be the possibility of integrating options for the in-situ monitoring of reactions, such as X-ray and Raman techniques [47][48][84][85][86][87]. In conclusion, in recognizing that both photochemistry and mechanochemistry

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

• significantly spurred the scientific curiosity of researchers over the past few decades [1]. Intensive studies revealed that this subtle code of cell surface glycans is extensively responsible for monitoring a plethora of diverse biological phenomena like post-translational modification of proteins [2][3

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

• assigning specific contributions of each to the observed binding affinities. Even so, 1H NMR titration experiments with phosphine oxides still allow us to partially resolve these two forces by monitoring the proton of the CF2H group. Such issues are particularly salient when quantification methods that rely

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

• , stirring, heating, and cooling modules for enhanced versatility. In addition, the platform is capable of performing under inert and low-pressure atmospheres, handling separation steps, and pressure sensing for reaction monitoring. Its efficacy and robustness were confirmed through the successful synthesis

• medium for enhancing the optimization of the Buchwald–Hartwig amination intermediate, which is crucial for synthesizing the drug olanzapine [47]. The reactor setup was integrated with spectroscopic and chromatographic in-line analytical tools, enabling real-time monitoring of products and reaction

• , each comprising 650 µL within a slug flow reactor [48]. This innovative system features precise monitoring of the reaction slug through a dedicated array of phase sensors and an algorithm designed for detecting its passage. As a result, the workflow delivers a notable boost in productivity, surpassing

Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives

• Shuxian Qiu,
• Duan Dong,
• Jiahui Li,
• Huiting Wen,
• Jinpeng Li,
• Yu Yang,
• Shengxian Zhai and
• Xingyuan Gao

Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274

• was funded by the Youth Innovation Talents Project of Guangdong Universities (natural science) in China (No. 2022KQNCX052), Research and Innovation Team for Wastewater Treatment and Monitoring of Guangdong University of Education (No. 2024KYCXTD016), the quality and reform project of Guangdong

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• bis- and tris-norbornadienyl-substituted benzene derivatives. Photometric monitoring of the irradiation of 1h (A), 1i (B), 1j (C), 1k (D), 1l (E), and 1n (F); λex = 315 nm (1h, 1i, 1k, and 1l) or 340 nm (1j, 1n). Insets: plot of absorption at long-wavelength maximum versus irradiation time t

• . Photometric monitoring of the irradiation of 1i (A) and 1l (B) in the presence of [Ru(phen)3](PF6)2; λex = 520 nm. For clarity, the absorption of the sensitizer has been deducted. Insets: plot of absorption at long-wavelength maximum versus irradiation time t [38]. Photoinduced [2 + 2]-cycloaddition

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• − in the aqueous state at a pH of 7.4 due to its weak acidic nature and high solubility in water (80 mM at 37 °C) [6]. Elevated levels of H2S in groundwater pose high risks to both human health and aquatic ecosystems [7], compelling rigorous monitoring of water sources. Even though sensors for

Photoluminescence color-tuning with polymer-dispersed fluorescent films containing two fluorinated diphenylacetylene-type fluorophores

• Kazuki Kobayashi,
• Shigeyuki Yamada,
• Motohiro Yasui and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2682–2690, doi:10.3762/bjoc.20.225

• clearly indicates that the PL originates from a single fluorophore. Using a 1 wt % PMMA film blended with 1a and 1c in an 80:20 ratio (Figure S2g in Supporting Information File 1), the excitation spectrum obtained by monitoring the long PL wavelength derived from 1c was also in good agreement with the

• EFRET values were 55% and 46%. Both mixtures showed a relatively fast energy transfer, which likely caused the PL of 1f to be the major component. Furthermore, the excitation spectrum obtained by monitoring the long PL wavelength originating from 1f using a 1 wt % PMMA film blended with 1a and 1f in an

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• restricted to the recommended one. The reactions should be monitored continuously, and to be quenched as and when recommended in this section. Prolonged heating without monitoring is not recommended. A picture of the experimental set-up is included in Supporting Information File 1 (Figure S31). Single

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

• 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

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

• thioesters 2 (2a as an example) A mixture of (E)-3-(ethylthio)-1-phenyl-3-(phenylamino)prop-2-en-1-one (1a, 70.8 mg, 0.25 mmol) and DBSA (87.9 mg, 0.25 mmol) in water (2 mL) was stirred at reflux in an oil bath under air for 5 h until 1a was completely consumed, as confirmed by TLC monitoring. Then, the pH

• water (2 mL) was stirred at reflux in an oil bath under air for 24 h until 1a was completely consumed, as confirmed by TLC monitoring. Then, the pH value of the reaction mixture was adjusted to neutral using a 10% CH3COOH solution, and the reaction mixture was extracted with CH2Cl2 (3 × 20 mL). The

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• atmosphere. The flask was cooled to 0 ºC, and stirred vigorously after that n-BuBr (11.30 mL, 105.12 mmol) was slowly added to the RB-flask, and the mixture was stirred for 24 h at room temperature (rt), until the reaction completed (TLC monitoring). Then the reaction mixture was quenched with water, and the

• different equivalents (2 equiv for 12, 6 equiv for 15 and 9 equiv for 17) at 0 °C under N2 atmosphere. The red reaction mixture was stirred for 30 min at 0 °C, and further stirred at room temperature for 1 to 6 hours. After the reaction completion (TLC monitoring), the mixture was poured gradually into

• , 18) for 8 h. After the reaction completion (TLC monitoring), excess of triethylamine (TEA) was added to quench the reaction mixture. After the removal of the unreacted pyrrole in vacuo (the temperature of the water bath and the pressure were set to 80 °C and 80 mbar, respectively), the dark brown

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

• ) sample the glycan conformational space; ii) investigate how the glycan behaves in a solution (if the MD is performed in explicit solvent), describing carbohydrate–water interactions; iii) monitoring the intramolecular interactions. Usually, this information has to be further validated by performing

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• Information Supporting Information File 5: Experimental details, supporting figures, and copies of spectra. Supporting Information File 6: Monitoring of DA11 under visible-light irradiation. Supporting Information File 7: Monitoring of DA7 under visible-light irradiation. Supporting Information File 8

• : Monitoring of DA6 under visible-light irradiation. Acknowledgements We acknowledge the technical support from UCEA and ULS of PolyU. All authors sincerely appreciate Prof. Dr. Takanori Fukushima (Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology) for

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• (1.0 equiv) in anhydrous DMF (≈3.5 mL per mmol) was added K2CO3 (2.0–4 equiv) and BocNHCH2CH2Br (1.5–4 equiv), then stirred overnight at 60 °C. After the reaction was completed (TLC monitoring), the mixture was evaporated to dryness under reduced pressure. The residue was dissolved in EtOAc

• compound in anhydrous MeOH (≈10 mL per mmol) was added dropwise AcCl (1.0–3.0 equiv) at 0 °C, slowly warmed to rt, and stirred overnight. After the reaction was completed (TLC monitoring), the mixture was evaporated to dryness under reduced pressure. The residue was dissolved in MeOH, acetone was added

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• dissolved in DCM (10 mL), FeCl3 (30 mol %) added and magnetically stirred at room temperature. Within 2–30 h, the reactions went to completion (TLC monitoring), affording, at last, N,O-aminals 5a–r (42–82%) and the corresponding hemiaminals 6a–p (4–35%) after column chromatography (Scheme 3). An increased

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• determine the ISC quantum yield, ΦISC, using the well-studied photosensitizer [Ru(bpy)3]Cl2 (Rubpy) as reference for actinometry [78][79][80]. This approach involved employing identical excitation conditions at 355 nm (Figure 4A) and monitoring the GSB of Rubpy with a literature-reported difference

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• resulting DNA hairpin. The β-anomer of Va was introduced instead of the target dC in the DNA hairpin with TTC loop and tested in the 1H NMR-based assay monitoring A3A-catalysed deamination of dC hairpin (T(GC)2TTC(GC)2T, wherein C is deaminated) at a 150 mM salt concentration at pH 7.4. Recently, FdZ (IId

Monitoring carbohydrate 3D structure quality with the Privateer database

• Jordan S. Dialpuri,
• Haroldas Bagdonas,
• Lucy C. Schofield,
• Phuong Thao Pham,
• Lou Holland and
• Jon Agirre

Beilstein J. Org. Chem. 2024, 20, 931–939, doi:10.3762/bjoc.20.83