4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• pyrrolidine-2,3-diones 3b–e are not expected to affect the scope of the reaction (Scheme 2, Table 1). When the reaction between 3a (1 equiv) and methylamine (4) (4 equiv, 40% in water) was carried out in absolute ethanol (0.3 mL) at reflux, 4-(1-methylamino)ethylidene-1,5-diphenylpyrrolidine-2,3-dione (5a

• ) was obtained in 80.8% yield. Gratifyingly, substrate 3a is well soluble in methylamine solution (40% in water) and conducting the reaction between 3a (1 equiv) and methylamine (4) (40% in water, 0.3 mL, 47 equiv), without any other solvent added, the yield of product 5a increased to 92.2% (Table 1

• ). Therefore, excess methylamine (40% in water, 47 equiv), served as both the solvent and nucleophilic reactant in the above reaction. In the 1H NMR spectrum of 3a, there are two doublets of doublets at 4.40 ppm and 4.49 ppm corresponding to two methylene protons (CH2) which are diastereotopic and therefore

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• and nickel were used as the cathode and graphite as the anode, the efficiencies of the processes were very close to each other. The use of dry acetonitrile as the reaction medium significantly reduced the yield. These results indicate that water plays a crucial role in this reaction, as its

• optimization of the reaction, an HTe−Chem reactor was used in the presence of Me₄NOAc as the electrolyte. The use of NMP and Me₄NOAc was beneficial, as in many cases, adding water led to the precipitation of the desired product from the reaction mixture. A wide range of iminophosphoranes were synthesized

• according to the following mechanism via an anodic trimethylsilyl cyanide radical formation (Scheme 24). The formation of the Ph₃P=O as the side product was assumed to be due to the presence of water or oxygen in the reaction mixture, which competes with the aminating reagent. Electrochemical O–P bond

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• used it after isolation and characterization. In these cases, BINOL phosphate 5 was purchased, and used either without any further purification (Table 2, entries 5–7), or it was washed first with 2 N HCl solution, then rinsed with water, to remove possible traces of Ca2+, which could stem from

Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion

• Leon M. Friedrich and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57

• α-ᴅ-mannoside (MeMan) measured on the same plate as reference. This leads to relative inhibitory potencies, so-called RIP values. Because of limited water solubility, the samples had to be dissolved in DMSO and therefore, the effect of pure DMSO was also tested in every individual assay (cf

• , Figures S13–S16), the analysis of the testing results shows that determination of the inhibitory potencies of the various isomers is indeed valid in spite of the limited water solubility of the samples. Looking over the measured inhibitory potentials, it can be concluded that (i) the isomeric state of the

• like glycoclusters 1 and 2 are capable of many conformational alternatives and therefore, the control of molecular shape by photoisomerization of azobenzene linkers has its limitations. In addition, water solubility requires improvement. Furthermore, our study, combining synthesis, analysis of

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

• in 40 µL of water, followed by the addition of 12 µL of buffer (250 mM HEPES, 500 mM KCl, pH 7.0) and 6.0 µL of MgCl2 solution (20 mM). The aptamer was annealed by heat shock at 90 °C for 2 minutes and cooled on ice. Then, 2.0 µL of a ligand stock solution (3.0 mM, in DMSO) was added. The final

Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

• alkyl sulfate ionic groups. The X-ray crystal structure of the C1·Me6CHDA complex is reported. Host C1 is significantly less soluble in water (4 mM) compared to the analogous acyclic CB[n] host M1 which features sulfonate ionic groups (346 mM). Host C1 does not undergo significant self-association

• and water [1][2][3][4]. Building on this fundamental knowledge, supramolecular chemists created a variety of functional systems including supramolecular polymers, sensing ensembles, molecular machines, supramolecular separation phases, and drug delivery systems [5][6][7][8][9]. A primary subfield of

• important role driving the inclusion of Me6CHDA inside of C1 to form the C1·Me6CHDA complex. Of course, the inclusion of the hydrophobic cyclohexyl moiety inside the cavity of C1 provides a hydrophobic driving force for complexation in water. Given that C1 is a tetraanion and that Me6CHDA is a dication, an

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

• , conformations in which the two C–F bonds are aligned gauche will be favoured in water due to their high molecular dipole moment. A final layer of complexity is afforded by the stereochemistry of the 1,2-difluoroalkane motif: the various conformational factors described above will aggregate differently depending

• upon whether the 1,2-difluoro stereochemistry is threo or erythro. For example, the diastereoisomeric difluorinated stearic acids 14 and 15 (Figure 3) are found to have very different physical properties [28]. When deposited into a monolayer above a water phase, the threo-isomer 14 occupies a small

• be altered, too [44]. For example, consider compounds 26 and 27 (Figure 4), which are fluorinated analogues of the multiple sclerosis drug gilenya (25) [45]. The syn,anti-fluorinated stereoisomer 26 has a much higher water solubility than gilenya (25), attributable to the presence of new polar bonds

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• fluorinated amino acids that can be synthesized from a single starting material is a unique feature of this method, making it an important cornerstone of fluoropeptide chemistry. Experimental General information Air- and hydrolysis-sensitive reactions were carried out under exclusion of air and water in

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• ]. Accordingly, the electrolysis of monoester 9a in a 2:1 MeCN/H2O mixture in the presence of 0.025 M LiClO4 solution under constant current conditions (j = 12 mA/cm2) with graphite both as an anode and a cathode material afforded the desired N-tosylpyrrolidine 6a in 67% yield (Table 1, entry 1). The water

• amount of water was reduced from 33% to 17% (Table 1, entry 8 vs entry 7), an observation that might be useful for substrates of low aqueous solubility. However, further reduction of water amount to 5 equivalents completely inhibited the anodic oxidation of 9a, and only traces of the desired 6a were

• (entry 10, Table 1) in deuterated solvents (Scheme 2; for details, see Supporting Information File 1, page S40). Surprisingly, the electrolysis in a 5:1 mixture of MeCN-d3 and water delivered 11d without deuterium incorporation (Scheme 2, reaction 1). In contrast, the formation of deuterated 11d-D was

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• available and inexpensive Ru(bpy)3, along with a water-soluble, air- and moisture-stable Ni(dabpy)Br2 catalyst. Moreover, they demonstrated that this system works efficiently in aqueous conditions, making it highly suitable for applications involving antibodies. These characteristics make the method highly

• facilitated a site-specific covalent linkage to the antibody, resulting in the formation of a DAR 2 ADC precursor. For their ADC design strategy, the group selected a polyethylene glycol (PEG) linker, as it enhances the water solubility of the ADC, while the payload consists of the cytotoxic agent DM1, which

• aqueous media is essential for the modification of antibodies, as these biomolecules are typically dissolved in water or aqueous buffers to maintain their stability and activity. Antibodies are sensitive to their environment, and using a non-negligible amount of organic solvents or harsh chemical

Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• Agilent 1100 series preparative HPLC system [ChemStation software (Rev. B.04.03 SP1); binary pump system; column: Kinetex 5u RP C18, dimensions 250 × 21.20 mm; mobile phase: ACN + 0.05% trifluoroacetic acid (TFA) and water + 0.05% TFA; flow rate: 20 mL/min; diode array UV detector; 226 fraction collector

• mixture was stirred at room temperature overnight. The reaction mixture was suspended in water (25 mL) and extracted with CH2Cl2 (2 × 25 mL). The combined organic layer was evaporated to dryness to give a residue, which was dissolved in methanol (300 μL) and purified by preparative HPLC [ChemStation

• software (Rev. B.04.03 SP1); binary pump system; column: Kinetex 5u RP C18, dimensions 250 × 21.20 mm; mobile phase: ACN + 0.05% trifluoroacetic acid (TFA) and water + 0.05% TFA; flow rate 20 mL/min; diode array UV detector; 226 fraction collector. A gradient from 47 to 72% solvent B in 50 min was used

Sequential two-step, one-pot microwave-assisted Urech synthesis of 5-monosubstituted hydantoins from L-amino acids in water

• Wei-Jin Chang,
• Sook Yee Liew,
• Thomas Kurz and
• Siow-Ping Tan

Beilstein J. Org. Chem. 2025, 21, 596–600, doi:10.3762/bjoc.21.46

• hydantoins [19][20], we aim towards creating a more efficient procedure to access hydantoins. We are interested in the synthesis of hydantoins from amino acids and potassium cyanate in water due to its simplicity and environmental friendliness, which also precludes the use of water-sensitive and highly toxic

• Discussion As the first step of Urech hydantoin synthesis involved the N-carbamylation of amino acids, we carried out the microwave-assisted synthesis of urea derivatives in water, utilizing ʟ-phenylaniline as the representative amino acid. The optimal conditions for the N-carbamylation of ʟ-phenylaniline

• were first verified using different equivalents of KOCN at different temperatures in water under microwave heating conditions (Scheme 1, Table 1), and 5.0 equiv of KOCN and microwave irradiation at 80 °C produced the best yield for H1a (Table 1, entry 2). Inspired by the simplicity of the procedure, a

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• carbon atom, due to the readiness for losing a water molecule. Formaldehyde is commonly used in its polymeric form (paraformaldehyde) or in a 37% aqueous solution (formalin). The exceptional solubility of formaldehyde in water or biobased solvents, such as ethanol and glycerol, enhances the feasibility

• [17][18]. An important drawback of this solvent is the difficulty of its removal from the reaction crude, and extractions with water are commonly employed before purification. Depending on the reaction conditions, DMSO can be transformed into different products, e.g., under redox conditions, DMSO can

• ], DMSO [64], water, and even neat conditions [62]. In some cases, the same dihalomethane can be used as both the reactant and solvent. For example, Aguilar et al., proved that when using CH2Cl2 as both a solvent and a C1 source, they could obtain propargylamines 29 with good yields from secondary amines

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

• binding of tryptophan is therefore important for diagnostic and medicinal applications. Recently, we reported a glucose naphtho crown ether which is a chemoselective receptor for the esters of aromatic amino acids, in particular tryptophan, in water. Herein, we demonstrate that the same compound also

• binding of tryptophan in water [9]. However, the development of selective amino acid receptors in aqueous environments is challenging since it requires a combination of hydrophobic and polar interactions for binding [10][11][12]. As a result, the number of reported selective receptors for tryptophan in

• in water [21]. Crown ether 1 is particularly suited for the sensing of Trp methyl ester, which it binds with a higher affinity than the Phe and Tyr esters. Additionally, the binding of Trp-OMe results in a highly efficient fluorescence quenching of the naphthalene unit in the receptor. Herein, we

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

• , dried over 4 Å molecular sieves); quinine hemisulfate salt monohydrate (Fluka); sulfuric acid (EMD Chemicals); diethyl ether anhydrous (EMD Chemicals, ACS grade); chloroform-d (CDCl3, Cambridge Isotope Labs, 99.8%); hexafluorobenzene (C6F6, Oakwood Products); deionized distilled water (purified with a

• Barnstead NANOpure Ultrapure Water system, producing water with a final resistance of at least 18 MΩ); and silica gel (Sigma-Aldrich, 70–230 mesh, 60 Å). For HPLC separations: acetonitrile (Fisher Scientific ACS grade); toluene (Fisher Scientific, ACS grade); and heptane (Mallinckrodt Chemicals, ACS grade

• were extracted with Et2O and washed four to six times with doubly distilled water removing the aqueous layer each time. Anhydrous MgSO4 was added to the organic layer and passed through silica gel with DCM as the eluent. The organic layer was then concentrated to dryness. Yield (isolated): 9-H-10-BnF

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

• azobenzene is that the switching efficiency decreases sharply with increasing water content in the solvent. In a recently published paper, we reported that replacing one CH2 group in the bridge with NCOCH3 not only confers intrinsic water solubility, but also largely eliminates the problem of reduced

• neurotransmitters [10][11] or as switching units for potential dependent potassium channels [12]. Compared to the Z → E conversion rate of 92% (in n-hexane) of the parent diazocine the conversion in water/DMSO mixtures is decreasing with increasing water concentration (73% in water/DMSO 9:1) [8][9][10][11][12

• ]. Moreover, the parent diazocine is insoluble in water (precipitation in water/DMSO > 9:1). Substitution with polar substituents such as CH2NH2 provides water solubility, however, it does not restore the high Z → E conversion rates of the parent system in organic solvents, which is a disadvantage, since

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

• a greater or lesser extent, in all the solvents tested except in water (Table 1, entry 19), where the mixture remains unchanged after 100 hours. The enantiomeric ratio of the diastereomer anti-1 depends on the solvent used, with toluene (Table 1, entry 22) providing the best results. Finally

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

• of organic solvents [34] required for light-mediated transformations including on- and in-water approaches [35][36][37], the use of supercritical CO2 as solvent [38], and the melting point depression strategy [39]. However, a more drastic option would be to remove the solvent: no solvent is the best

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• water (Figure 2A) [71][72][73], or by binding a hydrophobic substrate and holding it close to a functional(ized) rim (e.g., as in cyclodextrins) that performs a reaction (Figure 2B) [74][75][76][77][78][79]. These effects are driven mostly by effective concentration/molarity (i.e., proximity of reacting

• phosphodiesters by 105–107 by electrophilic activation of ester and nucleophilic activation of water or peroxide at the metal ion [101][102]. The takeaway message is that polarization is most effective when it is bifunctional. In enzymes, there is never just a nucleophile – there is always a metal, “oxyanion hole

• a size-selective space [105][126][129][130][132][134]. A key advantage is that these capsules have been made on multi-hundred-gram scales and can be recycled [132]. Additionally, control of structural or bound water by the capsule [105] and properties such as a lowered pKa inside [125] demonstrate a

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• confirmed the presence of 6 that similarly co-eluted with 3 and 7 that completely overlapped with 4 on HPLC under our standard conditions (MeCN/0.1% TFA in water, 10%→60% 0→7 min, 60%→100% 7→10 min, 100% 10→15 min) (Figure 3). The identity of these impurities was further confirmed by independent synthesis

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• represent molecular switches of optical and fluorescent properties under sequential addition of CN− and Hg2+ ions and the transformation cycle presented in Scheme 3 can be repeated at least 5–6 times. The resulting compounds 7b and 8a,b have extremely low water solubility, which makes it impossible to

• prepare concentrations sufficient for studying cellular cytotoxicity. In this regard, 1,3-tropolone 7a, which has an acceptable level of solubility in water, was used for biological testing. The in vitro cytotoxic activity was investigated with A431 skin cancer and H1299 lung cancer cell lines. A standard

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

• of pyrazolo-1,2-benzothiazine derivative 5 A solution of compound 4 (269 mg, 1 mmol) in ethanol (10 mL) was refluxed with excess of hydrazine monohydrate for 24 hours. After the completion of reaction, unreacted hydrazine was removed under vacuum. Cold acidified water was poured into the residue

• . Yellow-colored precipitates of product 5 were formed which were separated via filtration followed by washing with excess of water. After drying, recrystallization was done with ethanol. Mp 265–266 °C; yield: 221 mg (88%). Synthesis of pyrazolo-1,2-benzothiazine-N-aryl/benzyl/cyclohexylacetamides 7a–h

• diluted with cold water and acidified with 5% cold HCl. The solution was allowed to stand for 15 minutes to complete precipitation. Precipitates were collected via filtration and washed with excess distilled water. The dried product was then recrystallized from absolute ethanol. Synthesis of pyrazolo-1,2

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• (2c) or 4-hydroxy-2H,5H-pyrano[3,2-c][1]benzopyran-2,5-dione (2d) in yields up to 51% (Scheme 6). Furopyrimidines 7a–f were obtained by reacting bromonitroacrylates 1a,b with representatives of substituted pyrimidines 2e–g. The reactions proceed successfully by refluxing in a water–alcohol (in the

Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• isolated from a lepidopteran larva found on the leaf litter buried in the soil, on October 6, 2012. Cultivation and extraction Samsoniella aurantia was cultivated on potato dextrose agar (PDA: 200 g potato, 20 g dextrose, 15 g agar in 1 L distilled water, Difco). Mycelial plugs, each with a diameter of 7.0

• mm, were inoculated with rice in 10 × 1 L Erlenmeyer flasks, each containing 180 g of rice and 180 mL of distilled water that were foremost autoclaved, and the mixture was incubated for 16 days under static conditions at room temperature until full mycelial growth was achieved. Upon reaching optimal

• evaporation at 40 °C, forming a semi-solid residue dispersed in water. Liquid–liquid extraction against EtOAc (1:1) was conducted twice. The organic phases were combined, filtered, and evaporated under vacuum, while the aqueous phase was discarded. Isolation of compounds 1–6 The obtained organic crude extract

Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory

• Misato Suganuma,
• Daichi Kitagawa,
• Shota Hamatani and
• Seiya Kobatake

Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16

• dropwise to the solution at −78 °C, and the mixture was refluxed for 20 min. Perfluorocyclopentene (1.2 mL, 8.7 mmol) was added, and the mixture was stirred for 2 h. An adequate amount of distilled water was added to the mixture to quench the reaction. The reaction mixture was neutralized by an aqueous HCl

• mixture was refluxed for 40 min. Perfluorocyclopentene (2.2 mL, 17 mmol) was added, and the mixture was stirred for 5 h. An adequate amount of distilled water was added to the mixture to quench the reaction. The reaction mixture was neutralized by HCl aqueous solution, extracted with ether, washed with

• solution at −78 °C, and the mixture was refluxed for 40 min. 2-Methyl-3-(perfluorocyclopent-1-en-1-yl)benzofuran [68] (0.73 g, 2.3 mmol) dissolved in THF (5 mL) was added, and the mixture was stirred for 2 h. An adequate amount of distilled water was added to the mixture to quench the reaction. The