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

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

• 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

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

• red-shift of the emission peak. Keywords: arene–perfluoroarene interaction; decafluorobiphenyl; fluorinated triphenylene; fluoroarene nucleophilic substitution; organolithium; Introduction Non-covalent arene–fluoroarene intermolecular interactions [1][2] are drawing increasing attention due to their

• (λem = 402 nm for PH8) and 460–500 nm for G66, with absolute quantum yields of 30% and 32%, respectively. Further, their fluorescence spectra in solutions show some solvent polarity influence, with a substantial red shift as the solvent polarity is increased. In thin film, the single luminescence

• maximum is shifted to 450 nm (518 nm) and 610 nm for F6 (PH8) and G66, respectively. The thin film emission of G66 is red-shifted by about 120 nm compared with its solution, while the one of F6 is red-shifted only by 30 nm. This huge difference in thin film emission can be explained via their

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• inhibitors, and their effects were investigated using the Amplex-Red® kit in C. elegans. Individuals exposed to compounds 2a, 2b, 2c, 2d, 2e, and 2f at a concentration of 1 mM were analyzed for AChE activity in their extracts. The results revealed significant inhibition of AChE levels, with compound 2e

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

• light irradiation. There are a few reports on red light-mediated transformations using other pyrrolic macrocycles, such as thiaporphyrin [94], phthalocyanine [95], and subphthalocyanine [96]. Porphyrin macrocycles can also absorb red light (Q bands at 518, 553, 592, and 648 nm with extinction

• coefficients around 104 M−1 cm−1), but they had not been used as photocatalysts in red light-induced processes until very recently. In 2022, Gryko and co-workers screened metal-free porphyrin macrocycles for various organic photochemical reactions that proceed via both oxidative and reductive quenching under

• red light irradiation [97]. Firstly, they evaluated the photoreductant role of metal-free macrocycles, H2TPP (18) and PPIX 78, in the red light-induced C–H arylation of different substrates such as furan, coumarin, thiol, pivalamide, aryl thiaether and the selenium equivalents. Use of both macrocycles

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

• is necessary to accomplish a reasonable balance between the MOST parameters. Hence, to increase the energy density and to induce a decent red shift of the absorption, two, three or even more norbornadiene units may be combined in one integral molecule by attachment to a shared, linking arene unit

• UV range [30]. Therefore, we aimed at further modification of the core structure of bis-and tris-norbornadienes, which may lead to a more pronounced red shift of the absorption while maintaining the high energy density. As this has been shown in other cases already [34], we anticipated that the

• substitution patterns, the compounds 1h–l,n showed the characteristic long-wavelength bands with maxima between 310 nm (1k) and 345 nm (1n) and low-energy zero onsets from 345 nm (1k) to 420 nm (1n). Hence, the red shift of the absorption bands correlates with the size of the respective π-system of the

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• , the A domain (gray rectangles in a) is responsible for activating the substrate BB to be incorporated, and the substrate BB specificity is dictated by the nonribosomal code (the 10 residues that defines its binding pocket, small red circles). Algorithms for A domain substrate prediction were trained

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

• Anastasia I. Ershova,
• Sergey V. Fedoseev,
• Konstantin V. Lipin,
• Mikhail Yu. Ievlev,
• Oleg E. Nasakin and
• Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

• dimethylamino group, were studied (Table 1 and Figure 3). It was found that in most solvents, compound 1i was characterized by a single pronounced absorption maximum in the range of 503–525 nm that red-shifted upon increasing the solvent polarity. In formic acid, due to the protonation of the dimethylamino

• visible region of the spectrum (from blue to red, Figure 3B and Figure 4). Acidic solutions were the most blue-shifted due to the formation of the protonated form 1iH+ (Scheme 2). Two emission maxima were observed in acetic acid and associated with the corresponding absorption maxima. The first, located

• color from blue to orange (Figure 7, top). The most blue-shifted emission was observed for stilbazole 1a without additional substituents. The introduction of an electron-donating group led to a red shift of the emission in accordance with increasing donor strength and number of substituents. Stilbazoles

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• their activity against various types of cancer. N-Glycosides of indigo, indirubin, and isoindigo, blue, red, and yellow sugars, turned out to be of special interest because of their high cancerostatic activity and structural novelty. The present article provides an account on the synthesis and

• myelocytic leukemia [5][6][7]. Indirubin, a red isomer of indigo, is an ingredient of indigo naturalis active against various cancers. Since the 1990s, we are witnessing a renaissance of the chemistry of indirubins because of their activity as potent inhibitors of several kinases, such as GSK-3β and CDK’s [8

• , indirubin, and isoindigo which can be regarded as blue, red, and yellow sugars, respectively. Review Indigo-N-glycosides (blue sugars) In 2002, Laatsch and Maskey reported the isolation of the akashins A, B and C, indigo-N-glycosides, from terrestric Streptomyces (Scheme 2) [17][18]. These natural products

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

• equation; LoD = yB + 3sB. yB is the signal associated with the blank and sB corresponds to the standard deviation of the blank [22][23]. LoD: [Tb.1·3Cu]3+ 0.63 μM, λem = 544 nm. Previously reported lanthanide complexes [12][16][17]. Absorption (red line), excitation (yellow line, λem = 615 nm), and

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

• Dmitriy Yu. Vandyshev,
• Daria A. Mangusheva,
• Khidmet S. Shikhaliev,
• Kirill A. Scherbakov,
• Oleg N. Burov,
• Alexander D. Zagrebaev,
• Tatiana N. Khmelevskaya,
• Alexey S. Trenin and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

• the formation of a coordination bond; the benzene moiety is located in a hydrophobic pocket. bThe conformations of compounds 4a–e are identical, whereas the position of compound 5e (red) is significantly different. Reaction of 2-aminoimidazole (1) with N-substituted maleimides (2) and N

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

• dependency on the amount of PyBA added. The absorption spectra of catC60-lip and C60-lip were compared in PBS(–) (Figure 3). At two different concentrations, no significant change was observed in catC60-lip, whereas broadening and a red shift were observed in C60-lip at higher concentrations (10 mol equiv

• (–) and DMSO under irradiation for 30 min by blue LED lamp. In the ESR spectra, signals corresponding to the adducts are indicated with red (4-oxo-TEMPO in a), blue (DMPO-OH in b), and green (DEPMPO-CH3 in c) arrows. Acknowledgements The authors thank Dr. Ebert from ETH Zurich for his support on ESR

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

• and effective luminescence color-tuning method is proposed to investigate the photoluminescence behavior of two-component polymer dispersion films blended with two types of fluorinated diphenylacetylenes, namely blue- and yellow- or red-fluorescent fluorinated diphenylacetylenes. It is confirmed that

• photoluminescence (PL) have been developed, whereas red PL with PL wavelengths in the long wavelength region is considered difficult to achieve owing to the energy gap law [11][12][13]. Over the past few decades, our group has been vigorously pursuing the exploration of functional molecules with a linear

• suppresses the formation of the twisted ICT state, resulting in red fluorescence even in the solid state (Figure 2) [23]. The precise tuning of molecular and electronic structures has made it possible to produce a wide range of PL colors. However, the development of white-light-emitting materials, which are

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• by a red sphere. (B) Schematic representation of the two possible ring-opening reactions of PO in the presence of activated CO2. Symmetric FLP scaffolds considered in the first study. X denotes N or P. Subset of FLP scaffolds considered in the catalyst optimisation study. Substituents and labels are

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

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

• introduction of N-aryl units during the synthesis is rendered difficult owing to steric hindrances. For example, N-phenyl-substituted TATA+ cation 1b+ (Figure 1) [26] exhibited slightly red-shifted absorption and emission, with a higher quantum efficiency compared to those of N-alkyl-substituted TATA+ cations

• , 0.209 mmol, 19%) as a red solid. Rf 0.33 (MeOH/EtOAc/CH2Cl2 1:2:8); 1H NMR (600 MHz, CDCl3, 20 °C) δ (ppm) 7.68 (t, J = 8.4 Hz, 3H, TATA-H), 7.51 (t, J = 7.8 Hz, 3H, Ar-H), 7.44 (d, J = 7.8 Hz, 6H, Ar-H), 6.37 (d, J = 8.4 Hz, 6H, TATA-H), 2.10 (s, 18H, CH3); 13C NMR (151 MHz, CDCl3, 20 °C) δ (ppm

• % MeOH/CH2Cl2) and was recrystallized from CH2Cl2/n-hexane to afford 2+-PF6− (3.68 mg, 5.0 μmol, 68%) as a red solid. Rf 0.40 (5% MeOH/CH2Cl2); 1H NMR (600 MHz, CDCl3, 20 °C) δ (ppm) 7.63 (t, J = 8.4 Hz, 3H, TATA-H), 7.50 (t, J = 7.8 Hz, 3H, Ar-H), 7.43 (d, J = 7.8 Hz, 6H, Ar-H), 6.35 (d, J = 8.4 Hz, 6H

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• , 17, and α-ᴅ-talose 18. ORTEP diagram showing 50% thermal ellipsoid probability (except for 18): carbon (gray), oxygen (red), fluorine (green), chlorine (orange), bromine (dark red), iodine (purple), and hydrogen (white). Packing arrangement of compound compound 15; a) View down the b axis; b

• ) proposed intermolecular interactions involving halogens. ORTEP diagram showing 50% thermal ellipsoid probability: carbon (gray), oxygen (red), fluorine (green), iodine (purple), and hydrogen (white). Synthesis of halogenated talopyranose analogues 13–15, and 17 that include a 2,3-cis, 3,4-cis relationship

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

• experimental results. The red dots show the experimental values for a sulfuric acid mass fraction of 94% and the black dots show the experimental values for a sulfuric acid mass fraction of 98%. Nitration of IO with mixed acid. Values of k for different H2SO4 mass fractions and at different temperatures

Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• ). Halogen bonding dimer found in the crystal structure of 7Br. Ellipsoids are shown at 50% probability (carbon: grey, nitrogen: blue, oxygen: red, bromine: orange, iodine: purple) and hydrogen atoms are shown in standard ball-and-stick model (white). Halogen and hydrogen bonding is indicated dashed. 1H NMR

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• (red line). b) Cyclic voltammogram of iminoiodinane 2c (8.0 mM) with varying amounts of HFIP in 5.0 mL solution of MeCN (0.10 M TBABF4) under N2 atmosphere: 2c with no HFIP (black line); 2c with 5, 10, 15 µL HFIP (grey line); 2c with 25 µL HFIP (red line); only 25 µL (blue line). c) Diastereomeric

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

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

• structure of DAntM radical (left) and its spin delocalization on two anthryl units. (b) Plausible head-to-head σ-dimerization of the DAntM radical. (a) ESR spectrum of the DAntM radical (black line, Exp.) and its simulated pattern (red line, Sim.). (b) Hyperfine coupling constant of the DAntM radical. (a

• ) ESR spectrum of anthroxyl radical 5 (black line, Exp.) and its simulated pattern (red line, Sim.). (b) Hyperfine coupling constant of 5. (c) X-ray structure of 5. Hydrogen atoms are omitted for clarity. Cyclic voltammogram (CV) of DAntM cation. (a) CV measured with scan rate at 3.0 V s−1. (b) Scan

• rate dependency (0.1, 0.5, 1.0, 2.0, and 3.0 V s−1) of the redox wave. Measurement conditions: 100 mM n-Bu4NPF6 and 1 mM DAntM cation in CH2Cl2. Red arrows indicate the sweep direction. UV–vis–NIR spectra of (a) DAntM radical in toluene, (b) DAntM cation in TFA. Synthetic route to the DAntM radical

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

• profiles (ΔG298 in kJ mol−1) calculated at the ωB97X-D/6-31G(d,p)/PCM (in CH2Cl2). Absorption (blue) and fluorescence (red) spectra of 6a (2 × 10−5 M) in CH2Cl2. (a) Crosslinking reaction of PVC-N3 (x = 0.11) with compound 5. (b,c) Strain-stress curves of PVC-N3 before (blue) and after (red) crosslinking

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

• 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

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

• involving unusual ligands, useful tools can be employed to provide the parameters needed for running MD simulations. Charge calculations and electron density computations for glycan units can be performed using tools like the online RED Server [70]. Although information on force fields is usually available