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

• the optical properties of 18 in CHCl3 (c = 100 μM) by measuring its UV–vis absorption spectrum as well as its excitation and emission spectra. The UV–vis spectrum of 18 showed two absorption peaks at 334 nm and around 375 nm (gray solid line). When excited at 375 nm, the emission spectra of 18

• - and E- rings serve as hydrogen bond (HB) donors/acceptors to facilitate DNA alkylation at C21. UV–vis absorption (gray solid line), the emission spectrum (blue solid line), and the corresponding excitation spectrum (blue dashed line) of the imidate 18 in CHCl3 (c = 100 μM). aQuantum yield (Φfl

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

• established methods, including 1H NMR-based hydrogen bond acidity determination, UV–vis spectroscopy titration with Reichardt's dye, and 1H NMR titration using tri-n-butylphosphine oxide as a hydrogen bond acceptor. Our experiments reveal that the direct attachment of the CF2H group to cationic aromatic

• as the charge of the solute changes, complicating the Δδ-based direct assessment of HB acidity. To quantify the HB donation ability of both neutral and cationic species on a single scale, we chose an alternative strategy based on an established UV–vis spectroscopy titration method [52] with

• ). Reports in the literature show that the UV–vis absorption of the Lewis basic Reichardt’s dye disappears in the presence of some cationic HB donors [52]. We found similar results with 3b and likewise ascribe the unexpectedly small Kd to such limitations of this assay (Figure 3C and Figure S19 in Supporting

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

• spectroscopic (e.g., NMR, FTIR, UV–vis, Raman) characterization methods are commonly used in real-time reaction monitoring. To quantify the products of a chemical reaction, a calibration curve is required before the optimization campaign. The following sequential steps are typically employed to refine raw data

• repository to be employed freely for research purposes. In addition to HappyTools, there are other available open-source Python packages to analyze chromatographic and spectroscopic data. A cross-platform Python package named Aston can be used to process both UV–vis and MS data. The open-source library is

• . [70] assembled four complementary PATs, including in-line NMR, UV–vis, IR, and online ultra-high-performance liquid chromatography (UHPLC) to meticulously monitor the intricate three-step linear synthesis of the drug mesalazine (18, Figure 7) with a 1.6 g⋅h−1 throughput. In the first step, the

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• in 3, which consume the energy of the excited state. Figure 4 shows the UV–vis absorption spectrum of 3 in cyclohexane with the absorption edge at 561 nm and its emission spectrum with a peak at 580 nm. In the test windows of cyclic voltammetry (Supporting Information File 1, Figure S1), 3 exhibits

• clarification). Structure of (M,P,M)-3 in the crystal of 3·CH2Cl2 (carbon and oxygen atoms are shown as grey and red ellipsoid at the level of 50% probability, and hexyl groups and hydrogen atoms are removed for clarity). UV–vis absorption spectrum (black line) and emission spectrum (blue line, excited at 400

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

• HRMS spectrometry were in full agreement with the expected structures, and single-crystal X-ray diffraction analysis was conducted to confirm the structure of compound 7-H. Moreover, the photophysical properties of these PhFlOP derivatives were determined by UV–vis absorption and photoluminescence

• CCDC 2256875. The crystallographic details are summarized in Table 1, and the structure of 7-H is shown in Figure 1 as an ORTEP diagram. Photophysical properties In order to investigate the photophysical properties of the PhFlOP-based molecules 7, UV−vis absorption and photoluminescence (PL) studies

• were conducted. UV−vis absorption spectra of 7 in toluene solution at room temperature are shown in Figure 2, and the corresponding data are included in Table 2. The spectra in Figure 2a exhibit two major absorption bands at ≈290 nm and ≈340 nm. The band at around 290 nm might be induced by π→π

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• derivatives and the antiparallel stacking mode into columnar structures stabilized by arene–perfluoroarene intermolecular interactions were confirmed by the single-crystal structure of the alkoxy-free side chain analog, i.e., 1,2,4-trifluoro-3-(perfluorophenyl)triphenylene (F). UV–vis absorption and

• . Photophysical properties: UV–vis absorption and photoluminescence UV–vis absorption and fluorescence spectra of the synthesized fluorine polycyclic aromatic hydrocarbons Fn and Gnm were measured in solution (in various solvents) and thin film and the results are summarized in Figure 6 and Table S7 in Supporting

• Information File 1; F6 and G66 were chosen as representative examples. F6 and G66 show almost identical UV–vis absorption spectra, both of them possessing a very broad absorption band below 400 nm with two maxima at ca. 380 nm for the strongest peak, and at ca. 360 nm for the smaller one (λabs = 284 nm for

Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D

• Sasha Hayes,
• Yaoying Lu,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266

• biological profiling. Experimental General experimental procedures Specific rotations were recorded using a JASCO P-1020 polarimeter. UV data was recorded on a JASCO V-650 UV–vis spectrophotometer. NMR spectra were recorded at 25 °C on a Bruker Avance III HD 800 MHz NMR spectrometer equipped with a cryoprobe

Surprising acidity for the methylene of 1,3-indenocorannulenes?

• Shi Liu,
• Märt Lõkov,
• Sofja Tshepelevitsh,
• Ivo Leito,
• Kim K. Baldridge and
• Jay S. Siegel

Beilstein J. Org. Chem. 2024, 20, 3144–3150, doi:10.3762/bjoc.20.260

• separately titrated in order to obtain the UV–vis spectra of the acids in neutral as well as in deprotonated forms. Then, the same titration is done with a mixture of measured acid (FIC or BFC) and a reference acid. Using the spectral data from the titrations of mixtures the dissociation levels α = [A−]/([A

• measurements against different reference acids. A Perkin-Elmer Lambda 40 UV–vis spectrophotometer connected with optical fibre cables to an external cell compartment inside a MBraun Unilab glovebox filled with 99.999% pure argon was used for the spectrophotometric titrations. This setup ensured that during all

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

• increasing addition of TsOH into 67, an increase in electrocatalytic current appeared before the second reduction wave, while the first reduction at −1.14 V remained unchanged, suggesting formation of radical anion [67]˙− as the first step. UV–vis spectroelectrochemical measurements under bulk electrolysis

• the UV–vis spectrum revealed a red shift, indicating the presence of diprotonated H4TPP2+ macrocycle (Figure 21a). Fc addition into an air-saturated DCE solution containing 18 (H2TPP) and HTB led to oxidation of Fc to Fc+ and initiated the ORR process (Figure 20b). The rate of ferrocene oxidation (Fc

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• ]. Polyrotaxanes were prepared with a coverage ratio of 18, 46, 64, and 71%, and the conjugative polymer without any CD coverage showed a decrease of the UV–vis absorption and its broadening at around 40–55 °C than those at 25 °C, while this spectral change became weaker according to the increase of the coverage

Tailored charge-neutral self-assembled L₂Zn₂ container for taming oxalate

• David Ocklenburg and
• David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

• S20 in Supporting Information File 1). An average binding constant for oxalate of log K = 4.39 was obtained by UV–vis spectroscopy (Figures S21–S26 in Supporting Information File 1) since the intermediate-like exchange prevents the determination directly from the 1H NMR titration. The binding constant

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• ). Optical studies The UV–vis absorption spectra of 3a, 3b, and 3c are presented in Figure 5, and were carried out in dichloromethane solution (1 × 10−5 mol L−1). The absorption properties are summarised in Table 1. The UV–vis absorption spectra of the materials show a wide absorption band from 530 nm to 860

Synthesis of pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine derivatives via isocyanide-based multicomponent reactions

• Marzieh Norouzi,
• Mohammad Taghi Nazeri,
• Ahmad Shaabani and
• Behrouz Notash

Beilstein J. Org. Chem. 2024, 20, 2870–2882, doi:10.3762/bjoc.20.241

• their suitable fluorophores [49][50][51]. The UV–vis absorption and emission spectra of products 4 and 6 were studied in ethanol at 298 K. The absorption range (λabs) was 400–225 nm, and the emission range (λem) was 560–400 nm. These findings are shown in Figure S3 in Supporting Information File 1. An

• spectra of the products were obtained using an LS45 spectrometer from PerkinElmer. Elemental analyses were conducted using an Vario El CHN mode system from Elementar GmbH. The PL and the UV–vis spectra were obtained using a spectrofluorometer (LS45, PerkinElmer) and a Specord S 600 (Analytik Jena

• nuclear magnetic resonance) spectra of compound 6f (DMSO-d6, 300 MHz) at 25–85 °C; spectrum A: 25 °C, spectrum B: 35 °C, spectrum C: 45 °C, spectrum D: 55 °C, spectrum E: 65 °C, spectrum F: 75 °C and spectrum E: 85 °C. The crystal structure of 6a (CCDC2365306). UV–vis absorption for compounds 4a, 6c and

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

• magnetic resonance (1H NMR) spectra was recorded on a Bruker DRX400 spectrometer operating at 400 MHz. High-resolution mass spectrometry (HRMS) was performed using a Bruker BioApex 47e FTMS with an analytical electrospray source employing NaI for accurate mass calibration (ESI). UV–vis absorption spectra

• were measured at room temperature utilizing a Varian Cary 1E UV–vis spectrophotometer with a quartz cell of 10 mm path length. Luminescence emission spectra of aqueous solutions were captured at 23 °C using a Varian Cary-Eclipse fluorescence spectrophotometer set to phosphorescence mode, employing a

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• ][5]. Nonplanar porphyrins offer a marked difference in chemical and physical properties when compared to their planar compatriots [6], with relatively smaller HOMO–LUMO gaps resulting in an observed bathochromic shift in the UV–vis absorption spectrum [7]. The phenomenon of nonplanarity results from

• borylation of porphyrin 13 to yield 46. Mean geometrical parameters of OET-meta/para-ArylPP and out-of-plane and in-plane distortion magnitudes. Supporting Information Supporting Information File 9: Experimental methods, synthetic procedures, 1H, 11B and 13C NMR, VT-NMR, UV–vis, IR, HRMS (m/z)-APCI and HRMS

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

• free PyBA. Data analysis, including calculation of the phase transition temperature, was performed using the MicroCal PEAQ-DSC Software. UV–vis absorption measurement UV–vis spectra of DMPC liposomes (1 mM DMPC) with or without catC60 or C60 were measured in PBS(–) using a UV-3600 Plus absorption

• samples dispersed in phosphate-buffered saline (PBS(–)). UV–vis absorption spectra of liposomes (1 mM phospholipid) with C60 (a) or a cationic derivative of C60 (catC60) (b) added at various molar equivalents (mol equiv) to phospholipid. The equivalent of C60 added in C60-loaded liposomes (C60-lip) was

Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• studies; description of photochemical equipment; characterization data of compounds (1H, 13C and 19F NMR spectra, IR and UV–vis spectra). Acknowledgements The University of Genova is kindly acknowledged for the contribution to the acquisition of an NMR instrument (D.R. 3404 19/7/2018). We thank Mr

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• was studied by UV–vis and fluorescence spectroscopy. Keywords: cross-coupling; cyclization; heterocycles; palladium; Introduction Nucleobases contain the coded information and give DNA and RNA their typical structure. As a nucleobase, uracil is involved in numerous vital processes and is therefore a

• -based benzo[f]quinazoline-1,3(2H,4H)-diones C [65]. Furthermore, optical properties were analysed by UV–vis and fluorescence spectroscopy. Results and Discussion Synthesis Our strategy for the synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones is based on a four-step sequence and relies on a combination

• ), strong (s), medium (m), weak (w) or very weak (vw). UV–vis spectra were recorded on a Cary 60 UV–vis spectrophotometer and emission spectra were recorded on an Agilent Cary Eclipse fluorescence spectrophotometer. Basic and high-resolution mass spectra (MS/HRMS) were measured on instruments coupled to a

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

• -absorption studies UV–vis absorbance spectra of the 5-substituted-2-hydroxybenzophenones 4aa–ka were recorded in triplicates at room temperature (298 K) in ethanol at a concentration of 40 µM, in the range of 225–500 nm at 1 nm intervals [11]. The obtained data were corrected using calibration methods with

• ethanol as a blank. The critical wavelength (λc) and UVA/UVB ratio were calculated using Equation 1 and Equation 2, respectively, as shown below. Determination of SPF (sun protection factor) An ethanolic solution of the compounds 4aa–ka was prepared at a concentration of 200 μg/mL. The UV–vis absorption

• compounds 4ja, 4fb, and 4ma. Partial 1H NMR spectra of the aliquots (taken at different time intervals) from the reaction mixture. Plausible mechanism for the transition-metal-free decarbonylation–oxidation. UV–vis absorption spectra of selected synthesized compounds 4aa, 4cb, 4eb, and 4fb from 225–500 nm

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• desorption ionization time-of-flight mass spectrometry (MALDI–TOF MS). The synthesized ion pairs showed similar electronic properties in solution state. In CH3CN, 2+-BF4− exhibited UV–vis absorptions at 273, 350, and 524 nm and fluorescence emission at 607 nm upon excitation at 524 nm. The absorption band at

• ) 142.15, 140.66, 138.90, 136.12, 134.80, 130.88, 130.80, 110.29, 106.31, 17.63; 19F NMR (564 MHz, CDCl3, 20 °C) δ (ppm) −157.91 (s, 10BF4−), −157.96 (s, 11BF4−); UV–vis (CH3CN) λmax, nm (ε, 105 M−1 cm−1): 272 (1.28), 337 (0.06), 349 (0.09), 524 (0.21); MALDI–TOF MS (m/z) (% intensity): (positive) 594.3

• , TATA-H), 2.11 (s, 18H, CH3); 13C NMR (151 MHz, CDCl3, 20 °C) δ (ppm) 142.40, 140.77, 138.59, 136.46, 135.03, 130.73, 130.69, 110.66, 106.15, 17.61; 19F NMR (564 MHz, CDCl3, 20 °C) δ (ppm) −77.26 (d, J = 712 Hz, 6F); UV–vis (CH3CN), λmax, nm (ε, 105 M−1 cm−1): 272 (1.30), 337 (0.07), 349 (0.09), 523

Synthesis and reactivity of the di(9-anthryl)methyl radical

• Tomohiko Nishiuchi,
• Kazuma Takahashi,
• Yuta Makihara and
• Takashi Kubo

Beilstein J. Org. Chem. 2024, 20, 2254–2260, doi:10.3762/bjoc.20.193

• O–O bond cleavage to give compounds 1 and 5 (Scheme 2). Owing to the high reactivity of the DAntM radical, cyclic voltammogram (CV) was measured by using the stable DAntM cation, prepared from compound 3 oxidized by antimony(V) chloride, which can be characterized by 1H, 13C NMR, and UV–vis

• and cathodic sides became smaller, resulting in a reversible redox wave (Figure 5b). This indicates that the generated DAntM radical rapidly decomposes during the CV measurement, leading to the irreversible redox wave at slow scan rate. The UV–vis spectra of the DAntM radical and cation were shown in

• spectrum shape (Supporting Information File 1, Figure S10). On the other hand, the UV–vis spectrum of the DAntM cation, generated from 3 in TFA solution, showed an intense absorption band at 890 nm, which is the opposite trend compared to the DAntM radical. Conclusion The synthesis and characterization of

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• containing 1 g L−1 of a sample, 10 g L−1 of dithranol, and 1 g L−1 of sodium trifluoroacetate were mixed at a ratio of 1:1:1, and then 1 μL aliquot of this mixture was deposited onto a sample target plate. UV–vis absorption spectra were recorded on a JASCO V-670 spectrophotometer. Fluorescence spectra were

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

• derivatives were successfully characterized and their structures were established by means of the 1H and 13C NMR spectroscopy, besides further confirmation by mass spectrometry (see Supporting Information File 1). The UV–vis absorption, emission and time-resolved fluorescence spectra Emission and absorption

• spectra of thus synthesized truxenes (12, 14, 15, 16, 17, and 18) were analyzed in CHCl3 (Figure 2). The UV–vis spectrum of mono-acetyltruxene 12 displayed a broad band centered at 335.21 nm, an intense peak near 309.75 nm having a shoulder at 297.70 nm, and a less intense, broader band around 280.29 nm

• like 1H NMR, 13C NMR, and mass spectral data. The preliminary UV–vis absorption as well as fluorescence emission spectral data for thus prepared truxene-based compounds were recorded in chloroform and compared as well. Additionally, time-resolved fluorescence lifetime decays were also measured for thus

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• that Z–E isomerisation cannot be easily induced using gentle heating or visible light, as shown by the stability of the UV–vis absorbance spectra and SAXS patterns under these conditions (Figures S1 and S3, Supporting Information File 1). In contrast, irradiation with X-rays leads to significant

• stability of the Z isomer, AAP photoswitches are also susceptible to Z–E isomerisation on X-ray irradiation due to the presence of catalysing ionic and radical species from radiolysis of the surrounding water. This can be seen by a partial return of the UV–vis absorbance spectrum of AAPTAB from the Z to the

• effect, but also as the medium for structural rearrangements. Effect of acidification The effect of acidification on isomerisation was further investigated using UV–vis absorbance spectroscopy, where excess hydrobromic acid (HBr) was added to AzoTAB and AAPTAB samples (25 μM) that had been preirradiated

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• governed the regioselectivity. Reactivities of norcorroles with various reagents. Top and side views of the X-ray structures of a) 2a and b) 1 [2]. Mesityl groups and hydrogen atoms were omitted for clarity. Thermal ellipsoids are drawn at 50% probability. UV–vis–NIR absorption spectra of 1 and 2a in