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

• involvement of a fluorescent intermediate in the cascade synthetic process. Keywords: cascade reactions; copper-catalyzed three-component coupling; gold-mediated 6-endo hydroamination; tandem cyclizations; tetrahydroisoquinoline alkaloids; Introduction The bis-tetrahydroisoquinoline (THIQ) alkaloid family

• . The resulting 6-endo cyclization product 12 could not be isolated under these conditions, and instead, the unexpected formation of fluorescent transient intermediate 18 was observed. Dehydrogenative oxidation of the 6-endo-cyclized product 12 with transpositions of the double bonds conjugated to the

• Information File 1, Figure S2 [57], and the benzylic position on the THIQ ring [58]. Indeed, termination of the reaction just after 90 minutes instead of 20 h resulted in the isolation of the fluorescent intermediate 18 in 55% yield (Scheme S1, Supporting Information File 1). Even with the use of both

Hot shape transformation: the role of PSar dehydration in stomatocyte morphogenesis

• Remi Peters,
• Levy A. Charleston,
• Karinan van Eck,
• Teun van Berlo and
• Daniela A. Wilson

Beilstein J. Org. Chem. 2025, 21, 47–54, doi:10.3762/bjoc.21.5

• : a) Thermograph of PBLG-PSar: Showing dehydration with a peak around 70 °C. b) The fluorescent intensity of pyrene measured at 376.6 nm divided by the intensity at 387.6 nm tracked over temperatures between 20 °C and 80 °C. c) DLS measurement: demonstrating a slight decrease in hydrodynamic radius of

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• fluorescent chemosensors and probes [4][5][6], as well as materials for applications in organic light-emitting diodes (OLEDs) [7][8][9], organic field-effect transistors (OFETs) [10], and perovskite solar cells [11]. In this respect, replacing either one or more of the carbons or rings of a fluoranthene with

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

• channel blockade was determined by the measure of Ca2+ influx induced by K+-depolarization in SH-SY5Y neuroblastoma cells, previously loaded with the fluorescent dye Fluo-4AM. On the other hand, the antioxidant activity of the DHPs was evaluated using the ORAC-FL method. The most potent compounds

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

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

• unchanged. This represents a rare approach for the design of such fluorophores. Arylidene derivatives of pyrindane were found to be efficient fluorescent dyes showing a moderate to high emission quantum yield. The push–pull molecules were also characterized by a dual-state emission (in solution and in the

• ], positron emission tomography (PET) imaging [24], fluorescent probes and labels [25][26][27] detecting H2S in foodstuff, water, and living cells [28], Fe3+ ions [29], Hg2+ ions [30], and cyanide anions [31], for acid–base vapor sensing [32], and as candidate material for photonics devices, optical switches

• flexibility, high efficiency, and versatility, making them essential for modern high-tech applications. Despite the wide variety of known push–pull molecules, the number of fluorescent cores with synthetic potential for tuning the emission wavelength to achieve a full-emission spectrum is limited. Typically

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

• fluorescent-based sensors; notable features include large Stokes shifts, extended luminescent lifetimes, and precisely defined emission bands [15]. Typically lasting in the order of milliseconds, their extended luminescent lifetimes enable the implementation of time-gated detection methods, effectively

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

• fluorescence or phosphorescence from different luminescent centers in the polymer matrix should be combined, and the PL color can be precisely tuned by controlling the ratio of the PL luminescent materials [27][28][29]. In this study, we prepared polymer dispersion fluorescent films containing two compounds

• ) films Initially, we tested the PL behavior of polymer dispersion films containing fluorinated diphenylacetylenes 1a–g as a single component, as shown in Figure 3, because the PL behavior of fluorescent molecules dispersed in a polymer matrix generally differs from that in a dilute solution or the

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

• , meaning no drying is required of the material, the material itself needs to be fluorescent (but not quenching upon assembly) or the addition of a dye is required. Such dyes need to be able to stick with the fibres, rather than sitting in the pores. Therefore, the fluorescent material is either chemically

• attached to the molecules themselves or is interacting with them. Introducing fluorescent dyes to self-assembling systems affects their chemical and mechanical stability as the hydrophobic features can destabilise the self-assembled network [18]. This reliance on fluorescence labels or dyes leading to a

• use of fluorescence probes should be used in tandem with CLSM. For example, Raeburn et al. showed that the addition of molecular rotors and fluorescent dyes affects the bulk network of self-assembled materials using rheology. The co-packing was observed to alter rheological properties of the materials

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

• been widely investigated in the past decades for application as fluorescent dyes [3][4][5], chirality inducers [6][7][8], acceptors for photoinduced electron transfer (PET) [9][10], and components of supramolecular assemblies [11][12][13][14]. Owing to the stable π-electronic systems showing unique

• +) cations, used as visible light fluorescent dyes, have been synthesized via a nucleophilic aromatic substitution (SNAr) reaction with primary alkylamines (e.g., 1a+; Figure 1) [15][16]. The highly planar geometry of the TATA+ core unit induces π–π stacking structures in single-crystal and film states, as

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• -PAGE) and visualized by in-gel fluorescence scanning (Figure 6A). In this approach the tag is a suitable fluorophore. Previously, during an introduction period of a chemical proteomics workflow of activity-based protein profiling (ABPP), the resulting fluorescent bands might be simply cut out from the

• probe–protein interaction leading to disappearance of the fluorescent bands. A gel shift assay is a complementary strategy to validate the labeling of a specific protein (Figure 6B) [65][79]. The assay is based on an increased retardation of the probe-labeled protein on SDS-PAGE due to the addition of a

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• end, the DES mixture from cycle 3 of Table 8 following product extraction was electrolyzed at 100 mA constant current using glassy carbon electrodes until 2 F/mol of current had passed. This deposited a metal clump on the electrode that was removed and then analyzed using X-ray fluorescent

• using a scoopula for further use and analysis using a Thermo Scientific Niton XL3t X-Ray Fluorescent Spectroscopy analyzer. Product characterization 1-(4-Methoxyphenyl)-3-buten-1-ol [39]: 1H NMR (300 MHz, CDCl3) 7.27 (d, J = 8.58, 2H), 6.86 (d, J = 5.82, 2H), 5.83–5.73 (m, 1H), 5.17–5.10 (m, 2H), 4.67

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

• ][12][13]. The most promising applications of truxene-based systems have been found in organic photovoltaics (OPVs), dye‐sensitized solar cells (DSSCs), fluorescent probes, organic thin‐film transistors (OTFTs), lasers, organic light emitting diodes (OLEDs), liquid crystals, non-linear optical (NLO

Cage-like microstructures via sequential Ugi reactions in aqueous emulsions

• Rita S. Alqubelat,
• Yaroslava A. Menzorova and
• Maxim A. Mironov

Beilstein J. Org. Chem. 2024, 20, 2078–2083, doi:10.3762/bjoc.20.179

• in favor of the second mechanism. To identify the structure obtained on the surface of the droplets during the formation of the Pickering emulsion, we used fluorescent labels. Aminofluorescein was introduced into the CMC composition with a ratio of 3 mg per 1 g of cellulose using condensation in the

A new platform for the synthesis of diketopyrrolopyrrole derivatives via nucleophilic aromatic substitution reactions

• Vitor A. S. Almodovar and
• Augusto C. Tomé

Beilstein J. Org. Chem. 2024, 20, 1933–1939, doi:10.3762/bjoc.20.169

• synthesis of highly fluorescent DPP derivatives through straightforward nucleophilic aromatic substitution reactions with thiols and phenols. These nucleophilic substitutions occur at room temperature and manifest a remarkable selectivity for the 4-position of the pentafluorophenyl groups. Both symmetrical

• (disubstitution) and non-symmetrical (monosubstitution) DPP derivatives are formed in excellent overall yields. The optical properties of the newly synthesized compounds are also discussed. The new platform may be useful for bioorthogonal chemistry. Keywords: diketopyrrolopyrrole; fluorescent dye; nucleophilic

• used in a wide range of applications, namely as organic semiconductors [8], acceptors for organic solar cells [9][10], as fluorescent probes [11][12][13], or as photosensitizers for photodynamic therapy and antimicrobial photodynamic therapy [14][15][16][17]. DPP derivatives with improved performance

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

• obtain new fluorescent products [39]. Starting from perbenzylated β-C-glucopyranosyl aldehyde 26, 2-aminopyridine (1) and cyclohexyl isocyanide (11), they synthesized C-glucoside 28 (Scheme 11). β-C-Glucopyranosyl aldehyde 26 was obtained from ᴅ-glucose following a procedure already established [40

• nucleophilicity. In their second work about this topic, Prasad et al. synthesized 5-(3”-alkyl/arylamino-1”-azaindolizin-2”-yl)-2’-deoxyuridines 31 as new base-modified fluorescent nucleosides with high Stokes’ shift, potentially useful for investigating nucleic acid structure and functions. The authors

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• the sole isomer. Spiropiperidine steroids Recently, Sviripa et al. synthesized novel spiro fused-coumarinpiperidines from 5α-androstan-3-one derivatives as part of their efforts to develop fluorescent inhibitors of 17-oxidoreductases for androgen metabolism in prostate cancer [60]. Starting from

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• combinatorial chemistry [35], in analytical chemistry, in electrochemical redox processes, in crystal engineering, and as fluorescent, light emitting, corrosion inhibitors or several other materials [36][37][38][39][40][41][42]. The most used triazine is 1,3,5-triazine (or s-triazine) that can provide

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

• (Gibco). Then, hBM-MSCs (Lonza) were added to the culture dish and cultured for 3 days at 37 °C and 5% CO2 in an incubator. After incubation, the DAn macroscopic scaffold with cells attached was used directly for fluorescent microscopy measurements. UV–vis-absorption-spectral changes of DAn in THF

• fluorescent particles pointed at by orange arrows in (c) and (d) are the clustered hBM-MSCs. Illustration of the reversible visible-light-controlled ring closure and thermal-driven ring-opening-processes of DAn and supramolecular assemblies on different length scales. Synthetic pathway to DAn. Supporting

Synthesis and optical properties of bis- and tris-alkynyl-2-trifluoromethylquinolines

• Stefan Jopp,
• Franziska Spruner von Mertz,
• Peter Ehlers,
• Alexander Villinger and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1246–1255, doi:10.3762/bjoc.20.107

• with trifluoroacetoacetate [17], the synthesis from enaminoketones [18] and the gold-catalysed cyclisation of propargylanilines [19]. Aside from its pharmaceutical significance quinoline compounds have been reported as strongly fluorescent with applications as electroluminescence materials [20][21][22

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• recrystallization from boiling DMSO to obtain highly insoluble red-brown microcrystalline material. 1H and 13C NMR could not be recorded for the compound 3a given its extremely poor solubility in common organic solvents. Rf (CH2Cl2): 0.75, fluorescent orange spot; HRMS (DART): [M + NH4]+ calcd for C22H8N6, 374.1154

Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• . This method allows for the hybridization of complex bioactive and fluorescent-labeled carboxylic acids with diaryliodonium(III) salts. Keywords: auxiliary ligand; diaryliodonium(III) salts; hybridization; hypervalent iodine; organocarboxylates; Introduction Hypervalent iodine compounds are an

• ) carboxylate 7aj carrying a fluorescent-labeling group in 93% yield. Iodosoarenes 5b–f can be easily obtained by treating (dichloroiodo)arenes [41] or (diacetoxyiodo)arenes [42] with sodium hydroxide, by oxidation of iodoarenes with NaClO·5H2O [43], or by electrolysis [44]. The reaction scope of iodosoarenes

• of the fluorescent-labeling carboxylic acid 6j (see Supporting Information File 1, Figure S1). Thus, this post-fluorescence iodonium salt can be used for visual indication of the ligand exchange process, elucidating the arylation mechanism of diaryliodonium(III) salts for their further applications

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• source such as green LEDs or a compact fluorescent lamp (CFL) were used only a small decrease in yield could be observed, although 4 hours of irradiation were needed to reach full conversion using CFL (Table 5, entries 8 and 9). The concentration, a factor expected to play an important role in a three

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• change of the solutions from yellow to dark orange. Subsequent selective interaction with AcO− led to the restoration of the initial absorption and emission properties. Thus, the obtained compounds represent dual-mode “on–off–on” switches of optical and fluorescent properties under sequential exposure to

• change depending on the intensity of sunlight), photochromic tags for biological research and optical sensors [15][16][17][18][19][20][21]. To develop new dual-mode molecular switches capable of efficient modulation of optical and fluorescent properties, both upon irradiation with visible light and upon

• = F, Cl, Br, I, CN, SCN, NO3) did not cause similar changes in the absorption spectra. This process could be carried out at least 4 or 5 times, which allows modulating optical and fluorescent properties by sequentially adding Fe2+ and AcO− to the acetonitrile solution of compound 2a (Figure 8

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• electron-rich coordinating guests. Detection by fluorescence was implemented using competition experiments with dimethylaminostyrylpyridine (DMASP). Intercalated DMASP is not emissive, but its displacement by a guest releases its free fluorescent form, which can be detected. The group of Nabeshima reported

• with two bis-2,2’-bipyridyl ligands and bis-pyrene fluorescent units. The stable conformation of perhydroanthracene is with the two pyrene units in the equatorial position. Their close spatial proximity leads to the observation of an excimer emission. Upon Zn2+ coordination, the perhydroanthracene core

• , tweezers 36 bearing pyrene fluorescent groups and using either rhodium(I) or copper(I) complexes as switching units were reported [79]. Cu(I), which avoids the luminescence quenching effect of Rh(I), requires pyridine as an ancillary ligand to complex the metal center and open the tweezers. The