Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

• platinum(II) complexes with pincer ligand moieties [12]. Thus, the reaction of S/R-3 with platinum(II) precursor 4 in the presence of CuI and diisopropylamine afforded the target platinum(II) complex S/R-Pt in moderate yield. The identification of the complex S/R-Pt were carried out with 1H and 13C NMR

• optoelectronic applications. Experimental General information All reagents and solvents were of commercial reagent grade and used without further purification. Dichloromethane for spectroscopy was purchased from FUJIFILM Wako Pure Chemical Corporation. All compounds were identified by 1H , 13C NMR and ESI-MS. 1H

• and 13C NMR spectra were recorded on a Bruker Avance III 400 or JEOL JNM-ECZ600R spectrometer at 25 °C in chloroform-d1 or DMSO-d6. 1H NMR chemical shifts are expressed in parts per million (δ) relative to trimethylsilane (TMS) as a reference. Mass spectra were obtained with a Thermo Scientific

Symmetrical D–π–A–π–D indanone dyes: a new design for nonlinear optics and cyanide detection

• Ergin Keleş,
• Alberto Barsella,
• Nurgül Seferoğlu,
• Zeynel Seferoğlu and
• Burcu Aydıner

Beilstein J. Org. Chem. 2026, 22, 131–142, doi:10.3762/bjoc.22.6

• , 13C NMR, and mass spectrometry methods. Dye structures were designed with alkylaminophenyl groups, known for their various electron-donating properties, as donors, and the dicyanovinyl group, with its strong electron-withdrawing properties, as acceptors, conjugated with an indan-2-one core (Figure 1

• method (CM)) (Scheme 1, Table 1). All syntheses were also carried out with microwave irradiation (MWI), which had a short reaction time; however, no improvement in yield was achieved (see Supporting Information File 1). The structural analyses of the compounds were performed using 1H/13C NMR and mass

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• conditions. The reaction is carried out either in tetrahydrofuran in the presence of triethylamine or in methanol in the presence of fused potassium acetate. The structures of the isolated individual products were characterized by 1H and 13C NMR, IR spectroscopy, mass spectrometry, and confirmed by single

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• partial positive charge on the i-positioned carbon atom [36], confirmed by an unusually downfield shifted signal of the CH fragment in the 13C NMR spectrum (δ 160.4 ppm in CD3CN) [21]. Moreover, anion 2 underwent a nucleophilic attack onto the i-position by amines to form fluorescent 5

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• octahydropyrido[1,2-a]pyrimidinones 4a–d and hexahydrooxazolo[3,2-a]pyridones 5a–c was determined by IR, 1H, 19F, 13C NMR spectroscopy, two-dimensional NMR experiments, and X-ray diffraction analysis (XRD). The IR spectra of octahydropyrido[1,2-a]pyrimidinones 4a–d are characterized by reduced vibrational

• crystal 4a–d and 5a–c are in excellent agreement with the results of 1D and 2D NMR studies, enabling us to extend these structural assignments to other synthesized bicycles. The complete assignment of signals in 1H and 13C NMR spectra was performed using two-dimensional 1H-1H COSY, NOESY and 1H-13C HSQC

• . Supporting Information Supporting Information File 16: General synthetic procedures, characterization data, XRD analysis data and copies of 1H, 19F, 13C NMR spectra, IR spectra, HRMS spectra of all synthesized compounds. Acknowledgements Analytical studies were carried out using the equipment of the Center

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• standard open 40 μL aluminum pan under 50 mL/min nitrogen atmosphere. IR spectra were obtained on a Bruker ALPHA FT-IR spectrometer in KBr pellets or in neat. NMR spectra were recorded at 295 K on a Bruker Avance III HD 600 (600 and 150 MHz for 1H and 13C NMR spectra, respectively) spectrometer equipped

• with a Prodigy cryo-probehead or a Varian Unity Inova 500 (500 and 125 MHz for 1H and 13C NMR spectra, respectively), or a Varian Unity Inova 400 (400 and 100 MHz for 1H and 13C NMR spectra, respectively), or a Varian Gemini 200 (200 and 50 MHz for 1H and 13C NMR spectra, respectively) spectrometer

• MHz, CDCl3): 7.99 (d, 3J = 8.4 Hz, 1H), 7.95 (d, 4J = 2.1 Hz, 1H), 7.86 (s, 1H), 7.66 (dd, 4J = 2.1 Hz, 3J = 8.3 Hz, 1H), 6.83 (s, 1H), 4.35 (m, 2H), 4.30 (m, 2H), 3.24 (s, 3H); 13C NMR (150 MHz, CDCl3): 187.20, 149.26, 142.28, 138.57, 138.06, 135.76, 134.05, 133.80, 133.09, 125.83, 125.27, 120.48

Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• compounds 3n and 4n was carried out using torsion angle analysis and 13C NMR chemical shift calculations to evaluate the absence of expected signals in the NMR spectra of these compounds. Their photophysical properties were also assessed, confirming a preference for a fluorescence mechanism via an ICT

• efficient synthesis of eight novel imidazo[1,2-a]pyridine–thiazolidinone hybrids in high yields (up to 99%). A spectroscopic analysis of selected compounds was carried out, including torsion angle evaluation and 13C NMR chemical shift calculations, justifying the absence of expected signals in some cases

• scans) and 151 MHz for 13C NMR (20,480 scans), using an overnight experiment in DMSO-d6 at a concentration of 0.1 M. Specifically, the spectra showed either an absence of expected signals or a lack of signal multiplicity, which was apparent in both the 1H NMR and, more prominently, in the 13C NMR

Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B

• Si-Chen Yao,
• Jing-Si Cao,
• Jian Xiao,
• Ya-Wen Wang and
• Yu Peng

Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197

• structures of aglacins A, B, C, and E. Retrosynthetic analysis of (+)-aglacin B (2). Synthesis of cyclization precursor 5. Synthesis of (+)-aglacin B (2). Supporting Information Supporting Information File 16: Experimental procedures, characterization data, and copies of 1H/13C NMR spectra

Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• groups by sodium borohydride and then converted to chloromethyl groups by treatment with thionyl chloride, to give compound 2. The reaction of compound 2 with thiourea in THF gave compound 3 as a white solid in 96% yield. Compound 3 was characterized by 1H and 13C NMR in DMSO-d6 as a solvent (Figure 1

• = 14.3 Hz, 4H, 2 × 4 ArCH2Ar), 6.66 (s, 8H, 8 × ArH); 13C NMR (100.6 MHz, DMSO-d6, 297 K) δ 13.9 (q, dodecyl CH3), 22.2, 26.2, 29.0, 29.5, 29.8, 30.1 (t, dodecyl CH2), 31.5 (t, ArCH2Ar), 34.7 (t, CH2S), 75.0 (t, OCH2), 127.8 (d, ArH), 128.8 (s, ArC-CH2S), 135.0 (s, ArC-CH2S), 156.0 (s, ArCO), 169.4 (s, C

• 10.4.1 (GraphPad Software, Inc., San Diego, CA). Selectivity index determination: The selectivity index of compound 3 was calculated as the ratio of the IC50 in the cancer cell line to the IC50 in the non-malignant cell line, according to the following formula 1H NMR (left) and 13C NMR (right) spectra

Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions

• Udyogi N. K. Conthagamage,
• Lilia Lopez,
• Zuliah A. Abdulsalam and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192

• the compounds, while chloroform was used for cholesterol and lipid stock solutions. 1H NMR spectra were recorded using Bruker AV III 400 and Bruker AV III 500 spectrometers. 13C NMR was conducted on a Bruker AV III 500 spectrometer. All chemical shifts (δ) are reported in ppm, referencing residual non

Palladium-catalyzed regioselective C1-selective nitration of carbazoles

• Vikash Kumar,
• Jyothis Dharaniyedath,
• Aiswarya T P,
• Sk Ariyan,
• Chitrothu Venkatesh and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2025, 21, 2479–2488, doi:10.3762/bjoc.21.190

• thoroughly characterized by 1H and 13C NMR spectroscopy, HRMS, and single-crystal X-ray diffraction analysis (Figure 1). A range of solvents was subsequently screened; however, none provided an improvement over 1,4-dioxane for this transformation (Table 1, entries 2 and 3). In addition to AgNO3, other silver

Synthetic study toward vibralactone

• Liang Shi,
• Jiayi Song,
• Yiqing Li,
• Jia-Chen Li,
• Shuqi Li,
• Li Ren,
• Zhi-Yun Liu and
• Hong-Dong Hao

Beilstein J. Org. Chem. 2025, 21, 2376–2382, doi:10.3762/bjoc.21.182

• . Supporting Information Supporting Information File 34: Characterization data and 1H NMR, 13C NMR spectra of the compounds. Acknowledgements The authors sincerely acknowledge all of the anonymous reviewers for their valuable comments and suggestions. Funding We are grateful for financial support from the Qin

Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes

• Suvenika Perera,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176

• but insoluble in CHCl3, CH2Cl2, methanol, acetone, acetonitrile, and hexane; G2W4: soluble in CHCl3, CH2Cl2, acetonitrile, DMSO, and TFA but insoluble in methanol, acetone, and hexane). The new hosts G2W1–G2W4 were fully characterized spectroscopically (1H and 13C NMR, IR, MS) and the data is in

• deshielding effect of the lone pairs on the adjacent OCH3 group and the neighboring aromatic ring. Similarly, the number of resonances in the 13C NMR recorded for G2W1 (19 observed, 19 expected), G2W2 (17 observed, 17 expected), G2W3 (13 observed, 13 expected), G2W4 (11 observed, 11 expected) are also

• -insoluble acyclic CB[n]-type receptors that possess benzene (G2W4), naphthalene (G2W3), and triphenylene (G2W1 and G2W2) walls bearing methoxy substituents. The new hosts were fully characterized by 1H NMR, 13C NMR, IR, mass spectrometry, and X-ray crystallography (G2W1 and G2W3). We studied the efficiency

Research towards selective inhibition of the CLK3 kinase

• Vinay Kumar Singh,
• Frédéric Justaud,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Blandine Baratte,
• Thomas Robert,
• Stéphane Bach,
• Chada Raji Reddy,
• Nicolas Levoin and
• René L. Grée

Beilstein J. Org. Chem. 2025, 21, 2250–2259, doi:10.3762/bjoc.21.172

• Supporting Information Supporting Information File 26: Detailed experimental procedures and spectral data, kinase inhibition studies, molecular modelling studies, analysis of dose-dependent effect of VS-77 on the kinase activity of Mm_CLKs and copies of the 1H and 13C NMR spectra. Acknowledgements We thank

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• on a Bruker ALPHA FT-IR spectrometer in KBr pellets, ν̃ was reported in cm−1. NMR spectra were recorded at 295 K on a Bruker Avance III HD 600 (600 and 150 MHz for 1H and 13C NMR spectra, respectively) spectrometer equipped with a Prodigy cryo-probe head. Full 1H and 13C assignments were achieved

A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines

• Yuka Takeuchi,
• Mutsumi Kobayashi,
• Yuuka Gotoh,
• Mari Ikeda,
• Yoichi Habata,
• Tomohiko Shirai and
• Shunsuke Kuwahara

Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168

• ), 7.00 (dt, J1 = 8.7 Hz, J2 = 3.6 Hz, 4H), 3.86 (s, 6H), 3.68–3.46 (m, 6H), 3.20–3.12 (m, 2H), 1.12 (d, J = 6.6 Hz); 13C NMR (100 MHz, CDCl3) δ 159.3, 141.4, 140.7, 134.0, 133.2, 130.3, 128.2, 126.3, 126.0, 114.3, 63.4, 60.7, 55.4, 51.3, 13.3; IR (KBr) νmax: 3407, 2959, 1732, 1607, 1517, 1489, 1249, 1178

• central biphenyl moiety rotates freely, forming an equilibrium mixture of P and M conformers. Supporting Information Supporting Information File 9: Experimental procedures, characterization data including copies of NMR spectra (1H NMR, 13C NMR), CD spectra of (S)-2f and (R)-2f, theoretical calculations

Further elaboration of the stereodivergent approach to chaetominine-type alkaloids: synthesis of the reported structures of aspera chaetominines A and B and revised structure of aspera chaetominine B

• Jin-Fang Lü,
• Jiang-Feng Wu,
• Jian-Liang Ye and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162

• the 13C NMR spectrum. We have succeeded in preparing a single crystal from the oxidation products. Interestingly, the X-ray diffraction analysis [66] showed that the single crystal contained two diastereomers (19/20) with the structures displayed in Scheme 2. Similarly, the DMDO oxidation of

• cytopathogenicity in MDCK cells with IC50 values of 15.5 and 24.5 μM, respectively. Attracted by both their structure and bioactivities, we anticipated their synthesis. The author determined the structure by means of spectroscopic (1H, 13C NMR, HSQC, HMBC, and 1H-1H COSY), and MS analysis, and claimed that “their

• 1H and 13C NMR are methanol-d4 that is different from Tan’s work [21] who used DMSO-d6 to record 1H and 13C NMR spectra of (–)-chaetominine (1). Thus we undertook the synthesis of the proposed structures of aspera chaetominines A (12) and B (13). By adopting our first-generation strategy [57][58][61

Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid

• Yana I. Sakhno,
• Oleksander V. Buravov,
• Kostyantyn Yu. Yurkov,
• Anastasia Yu. Andryushchenko,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158

• control of the reaction, while oxygen-bridged heterocycles 4 are formed under thermodynamic control. The purity and structure of compounds 4 and 5 were established by elemental analysis, mass spectrometry, 1H and 13C NMR spectroscopy, and X-ray diffraction study (Figure 1). For example, the 1H NMR spectra

α-Ketoglutaric acid in Ugi reactions and Ugi/aza-Wittig tandem reactions

• Vladyslav O. Honcharov,
• Yana I. Sakhno,
• Olena H. Shvets,
• Vyacheslav E. Saraev,
• Svitlana V. Shishkina,
• Tetyana V. Shcherbakova and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2021–2029, doi:10.3762/bjoc.21.157

• and 13C NMR spectroscopy, and by X-ray diffraction study (see Experimental part). The 1H NMR spectra of compounds 5 are characterized by the following signals: a broad carboxyl group proton singlet at 12.10–12.17 ppm, an NH group proton singlet at 7.74–8.02 ppm, an aromatic protons multiplet at 6.52

• the 1H NMR spectra of quinoxalinones 9, a shift of the methylene groups signal to a weaker field (2.90–3.14 ppm and 2.63–2.77 ppm) is observed in comparison to compounds 8 (2.60–3.06 ppm and 2.14–2.35 ppm). Furthermore, comparison of the 13C NMR spectra of compounds 8 and 9 shows a characteristic

• /aza-Wittig combination involving KGA. Yields of compounds 5a–l. Yields of compounds 6a–d. Yields of compounds 8a,b,d,f–h and 9a–h. Supporting Information Supporting Information File 32: General synthetic procedures, characterization of compounds, 1H and 13C NMR spectra and X-ray data

Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

• Rasma Kroņkalne,
• Rūdolfs Beļaunieks,
• Armands Sebris,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154

• . Conditions screening for copper-catalyzed arylation–cyclization of propargylsilane 7d. Supporting Information Supporting Information File 4: Experimental data, synthesis procedures, 1H and 13C NMR spectra, and X-ray data. Funding This work was supported by the Latvian Council of Science Grant LZP-2023/1

Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization

• Miao Xiao,
• Liuyang Pu,
• Qiaoli Shang,
• Lei Zhu and
• Jun Huang

Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152

• ester 4. Optimization of conditions to convert diketone 15 into cyclopentanone 14.a Supporting Information Supporting Information File 42: Experimental procedures, characterization data and copies of 1H and 13C NMR spectra. Acknowledgements We thank Prof. Zhen Yang (Peking University) for helpful

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• , 13C 100.6 MHz). 1H and 13C NMR data are reported with reference to solvent resonances, and 31P NMR spectra were reported with respect to external 85% H3PO4 (0 ppm). All experiments were carried out using standard Bruker pulse programs. Infrared (IR) spectra were recorded on a Bruker Vector-22

Stereoselective electrochemical intramolecular imino-pinacol reaction: a straightforward entry to enantiopure piperazines

• Margherita Gazzotti,
• Fabrizio Medici,
• Valerio Chiroli,
• Laura Raimondi,
• Sergio Rossi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2025, 21, 1897–1908, doi:10.3762/bjoc.21.147

• procedures and physical data for the new compounds, copies of 1H and 13C NMR spectra of the prepared compounds. Acknowledgements The authors thank Prof. A. Puglisi (Università degli Studi di Milano) for valuable discussions. For the single-crystal X-ray diffraction analysis the Unitech COSPECT (Università

Preparation of spirocyclic oxindoles by cyclisation of an oxime to a nitrone and dipolar cycloaddition

• Beth L. Ritchie,
• Alexandra Longcake and
• Iain Coldham

Beilstein J. Org. Chem. 2025, 21, 1890–1896, doi:10.3762/bjoc.21.146

• ) are quoted to the nearest 0.5 Hz with values in hertz (Hz). 13C NMR spectra were recorded on the above instrument at 100 MHz. Low- and high-resolution (accurate mass) mass spectra were recorded on a Walters LCT instrument using electrospray ionisation (ESI). Synthesis of the aldehyde 4 Sc(OTf)3 (0.63

• Hz, 1H), 7.02 (td, J = 7.5, 1.0 Hz, 1H), 6.86 (d, J = 7.5 Hz, 1H), 4.27 (d, J = 9.5 Hz, 1H), 3.97 (d, J = 9.5 Hz, 1H), 3.23 (s, 3H), 3.17 (dd, J = 18.0, 1.0 Hz, 1H), 2.99 (dd, J = 18.0. 1.0 Hz, 1H), 2.44 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 196.7, 174.9, 145.0, 143.6, 132.0, 129.8, 129.0, 127.8, 127.6

• ), 4.25 (ddd, J = 11.0, 6.5, 1.5 Hz, 1H), 3.86 (d, J = 15.0 Hz, 1H) 3.70 (dd, J = 7.5, 1.5 Hz, 1H), 3.42 (d, J = 15.0 Hz, 1H), 3.22 (s, 3H), 3.08 (s, 3H), 2.55 (dd, J = 13.0, 11.0 Hz, 1H), 2.24 (dd, J = 13.0, 6.5 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 178.4, 175.2, 174.8, 142.9, 134.2, 128.8, 123.4, 122.3

Fe-catalyzed efficient synthesis of 2,4- and 4-substituted quinolines via C(sp²)–C(sp²) bond scission of styrenes

• Prafull A. Jagtap,
• Manish M. Petkar,
• Vaishnavi R. Sawant and
• Bhalchandra M. Bhanage

Beilstein J. Org. Chem. 2025, 21, 1799–1807, doi:10.3762/bjoc.21.142

• -disubstituted quinolone 3a along with 36% of 4-substituted quinolone 3a′ were observed during GC and GC–MS analysis, and the structures of both quinoline moieties were identified by 1H and 13C NMR spectroscopy. Encouraged by this result, we next examined the feasibility of the reaction with methanol as solvent