Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• reaction at 60 °C for 24 h. The crude reaction mixture was analyzed by 1H NMR measurement, which revealed the presence of the two diastereomers in the dimerized product with the molar ratio of chiral-2a/meso-2a = 97:3. The enantiomeric purity of recovered (S)-1a was determined to be 34% ee, while that of

• substrates rac-1a–c. Molybdenum-catalyzed asymmetric metathesis dimerization/kinetic resolution of racemic vinylcymantrenes 1a–c.a Supporting Information Supporting Information File 19: Experimental procedures, NMR spectra (1H and 13C) for all the new compounds, and chiral HPLC chromatograms. Supporting

Molecular tweezer–peptide conjugates disrupt the protein–protein interaction between survivin and histone H3 essential in mitosis

• Catherine Gsell,
• Philipp Rebmann,
• Karina Opara,
• Christine Beuck,
• Peter Bayer,
• David Bier,
• Ingrid R. Vetter and
• Thomas Schrader

Beilstein J. Org. Chem. 2026, 22, 557–567, doi:10.3762/bjoc.22.41

• various projects with tailored peptide tweezer conjugates: For example, the self-complementary ELTLGEFL sequence of the nuclear export signal in survivin was coupled to tweezers which rendered them selective for this important interface (NMR evidence, 1:1 stoichiometry, K/A mutants) and prevented the

• by computational modeling (MD and QM/MM simulations) as well as structural biology (NMR/X-ray). Following our powerful concept of reinforcing natural peptide–protein interactions by tweezer conjugation [9][10], we envisaged to attach molecular tweezers to the histone H3 terminus at a distance which

• lyophilization, the product 2a was obtained as fully protonated TFA salt (43%); deprotonation with equimolar aq. NaOH produced the sodium salt of 2a quantitatively. The analytical characterization of 2a turned out to be difficult, because even in DMSO-d6, most NMR signals remained very broad, and in part

Experimental and DFT studies on the regioselective methanolysis of 5-azido-9-oxabicyclo[6.1.0]nonan-4-yl 4-nitrobenzoate isomers

• İlknur Polat,
• Selçuk Eşsiz and
• Emine Salamci

Beilstein J. Org. Chem. 2026, 22, 547–556, doi:10.3762/bjoc.22.40

• epoxide ring and acetylation resulted in the formation of two corresponding chloro-acetate isomers. The structure of one of the chloro-acetate isomers was determined via crystallographic analysis and the other by 1D and 2D NMR spectroscopy. DFT computations confirm the regioselectivity of the methanolysis

• ) in pyridine and 4-(dimethylamino)pyridine (DMAP) in 95% yield. Treatment of azido nitrobenzoate 8 with m-CPBA gave a mixture of isomeric epoxides 9a and 9b with a combined yield of 97%. The formation and ratio of these isomers were determined by NMR spectroscopy, showing a 63:37 ratio (1H NMR) of 9a

• intermediate 12 with the anti-face of the benzoate to give compound 14. Similarly, the chloride anion attacks by SN2-type the epoxide ring of intermediate 15 to give the sole product 16. The structure of acetate 11 was investigated using 1D (1H and 13C) and 2D (COSY, NOESY, NOE-diff, and HMQC) NMR

Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• resolution electrospray ionization mass spectrometry (HRESIMS) and NMR spectra. However, the isomeric compound 3 could not be detected in the extract (Figure 1). Since 4 could be an artefact, built by oxidation of 2 during working up of the extract, and to finally confirm the structure, the isomeric

• diacetate (EDDA). However, synthesis of 2 was difficult. Despite numerous attempts, we only were able to get mixtures of both melifoliones with minor amounts of 2. Since all attempts to separate both isomers on a preparative scale failed, we were only able to record NMR spectra from a very small quantity of

• structure. The 1H NMR spectrum of 4 showed signals for 22 protons (Table 1) with a certain similarity to the melifoliones, but with an exchangeable signal found at δ 2.88 ppm, typical for a tertiary carbinol, instead of a phenolic OH-group at about δ 13 ppm, found in the spectra of the melifoliones. All 18

Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• exemplarily with a trifluorinated trisnorbornadienylbenzene that 19F NMR spectroscopy may be applied as a useful complementary method for the investigation of sequential photoreactions. The trisnorbornadiene core structure was used as it figures as promising scaffold for molecular solar thermal (MOST) energy

• trisquadricyclane. Even though the reaction can be monitored by photometry or by in situ 1H NMR spectroscopy, unambiguous assignment of the distinct intermediate mono- and bisquadricyclanes was not possible because of signal overlap. In contrast, this shortcoming is circumvented with in situ 19F NMR-spectroscopic

• analysis. Contrary to the 1H NMR spectra, the 19F NMR spectra show significantly fewer characteristic and sufficiently separated signals that allow the unambiguous identification of all photoproducts and, thus, their detection in the course of the photoreaction. Keywords: fluoroarenes; molecular solar

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• % yield. Its structure was confirmed by 1H NMR, 13C NMR, and HRMS. The uranium(VI) extraction efficiency of PCP HA was evaluated by solid–liquid extraction experiments, using uranyl acetate as the uranium source, with measurements performed by gamma spectroscopy. PCP HA demonstrated good performance

• using thin-layer chromatography, with the appearance of the characteristic red spot upon treatment with FeCl3 confirming the presence of the hydroxamic acid functionality. Moreover, the formation of the tetra-hydroxamic acid product was confirmed by 1H NMR spectroscopy in deuterated DMSO, as evidenced

• ester substrate. When this method was used, the 1H NMR spectra of the products revealed residual peaks corresponding to unreacted ester (Supporting Information File 1, Figure S8). This observation is consistent with the substrate-dependent behavior reported in that study, highlighting that the reaction

Synthesis of a HDAC inhibitor–nanogold probe for cryo-EM visualization in class I HDAC co-repressor complexes

• Wiktoria A. Pytel,
• John W. R. Schwabe and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2026, 22, 480–485, doi:10.3762/bjoc.22.35

• to its corresponding NHS ester 8 and residual starting material was removed by column chromatography. The Boc-protecting group was removed under anhydrous conditions in good yield and the structure of 9 was confirmed by NMR spectroscopy. Compound 9 was maintained as the TFA salt for the final step

• , and was stable for days stored at −20 °C (stability determined by 1H NMR, Figures S1–S4 in Supporting Information File 1). For the conjugation of 9 to Au–NH2, an excess of 9 was used to drive the conjugation reaction to completion. Unreacted 9 was then removed by repeated washing with water and buffer

• for assistance and guidance in Cryo-EM experiments. We thank Dr. Vanessa M. Timmermann and Dr. Rebecca Hawker for assistance in NMR analysis and Dr. Sharad C. Mistry for assistance in mass spectrometry. Funding We thank the following funders: EPSRC (EP/S030492/1 to JTH; EP/W02151X/1 NMR facility); MRC

Structural reassignment of compound 968, an allosteric glutaminase inhibitor

• Lindsey A. Albertelli,
• Sainabou Jallow,
• Chun Li and
• Scott M. Ulrich

Beilstein J. Org. Chem. 2026, 22, 455–460, doi:10.3762/bjoc.22.33

• anticancer drug target. Compound 968 is a glutaminase inhibitor that is widely used to probe cancer cells’ dependence on glutaminase activity. Here, we show by NMR spectroscopy and X-ray crystallography that the reported benzo[c]phenanthridine structure of compound 968 is incorrect; its true structure is the

• ] and the substrate scope of diketone, arylamine, and arylaldehyde was widened over the subsequent decades [25][26][27]. However, later reports by Martinez et al. [28] using X-ray crystallography and Kozlov et al. [29][30] using NOESY NMR showed that this three-component cyclocondensation reaction does

• reassigning the structure of the cycloaddition reaction product from benzo[c]phenanthridine 1 to benzo[c]acridine 2, we predicted that all three compounds are the benzo[c]acridine isomer 2. The 1H NMR spectra of all three compounds are identical, indicating that they share the same structure (Figure 3A). We

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• moieties (such as bis- or tris-MOMO-substituted phenyl substituents). Due to the steric hindrance, the trans-configured product with the phenyl substituents on the opposite side of the epoxy functionality is obtained. Additionally, the clean reaction process shown by TLC and the NMR spectrum of the product

Synthesis and stereochemical analysis of dynamic planar chiral oxa[7]orthocyclophene

• Yukiho Hashimoto,
• Yuuya Kawasaki,
• Kazunobu Igawa and
• Katsuhiko Tomooka

Beilstein J. Org. Chem. 2026, 22, 436–442, doi:10.3762/bjoc.22.30

• procedures, characterization data, copies of 1H and 13C NMR spectra, and optimized geometries of DFT calculations. Supporting Information File 26: Crystallographic information file of compound 1ac. Acknowledgements We thank K. Imamura (Evaluation center of material properties, IMCE Kyushu University) for

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• conserved 3-(4-(tert-butyl)phenoxy)propyl function at the imide nitrogen. The resultant naphthalimide–organylselanyl conjugates, NAP-SePh and NAP-Se(n-Oct), were characterised using various spectroscopic techniques, including FTIR, ¹H, ¹³C, ⁷⁷Se NMR and high-resolution mass spectrometry (HRMS). NAP-SePh was

• compounds, making it a viable alternative for introducing long alkyl chains into selenium-containing systems towards lysosomal membrane permeability (vide supra) [42][43][44]. After synthesis, compounds 7 and 8 were thoroughly characterised using multinuclear NMR spectroscopy ¹H, ¹³C, and ⁷⁷Se NMR

• (Supporting Information File 1, S11–S13 and S16–S18). In the ¹H NMR spectrum of compound 7, the tert-butyl protons appeared as a singlet at 1.27 ppm. The protons of the propylene linker chain resonated in the aliphatic region at 2.22, 4.08, and 4.37 ppm. The aromatic protons of the tert-butyl-substituted

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• tetraureacalix[4]arenes was obtained. Examination of the 1H NMR spectra of the tetraureas in CDCl3 showed that in most cases triazole heterocycles do not intervene the formation of homo- and heterodimeric capsules by these compounds. Thus, considering the synthetic value of CuAAC and amine transformations, p

• calix[4]arene 11 having four TBS-protected propargyl groups at the narrow rim in only moderate yield of 37% [9]. In our hands, according to the NMR spectra of the reaction mixture, under the reported conditions (>30 equiv of fuming HNO3 per calixarene aromatic unit in a 1:1 dichloromethane/acetic acid

• mixture, from 0 °C → rt, overnight) the nitration of calixarene 6 resulted in a mixture of exhaustively nitrated product 11, partially nitrated calixarenes having nitro and tert-butyl groups at the wide rims, and a large amount of other calixarene side product(s) having broadened and non-interpretable NMR

Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells

• Maryna V. Kachaeva,
• Agnieszka B. Olejniczak,
• Marta Denel-Bobrowska,
• Victor V. Zhirnov,
• Yevheniia S. Velihina,
• Stepan G. Pilyo and
• Volodymyr S. Brovarets

Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27

• Analytique, Université d’Orléans, Pôle de chimierue de Chartres, BP 6759, 45067 Orléans Cedex 2, France 10.3762/bjoc.22.27 Abstract Nine novel functionalized 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines were designed, synthesized and characterized using 1H, 13C NMR, IR spectroscopy, elemental analysis, and

• cyclocondensation products – [1,3]oxazolo[4,5-d]pyrimidines. Subsequent reaction with phosphoryl chloride in the presence of N,N-dimethylaniline converted these intermediates into 2,5-diaryl-7-chloro[1,3]oxazolo[4,5-d]pyrimidines II. The structures of compounds 1–9 were proven and confirmed by 1H and 13C NMR, IR

• were followed by TLC (Silica gel, aluminum sheets 60 F254, Merck). Melting points were recorded on a Fisher-Johns apparatus. 1H and 13C NMR spectra were recorded on a Varian Mercury spectrometer (400 and 101 MHz, respectively) or Bruker Avance DRX 500 spectrometer (500 MHz and 126 MHz, respectively) in

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• modifications and the use of the obtained compounds as building blocks. We also examined other nucleophiles suitable for the described domino-sequence. Thus, application of ethanol as solvent resulted in a mixture of the desired product 4b with the corresponding intermediate C (NMR ratio 88:12), however, longer

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• unsymmetrical oxaza[8]helicenes 5. Chiroptical features of oxaza[8]helicenes 5 and oxaza[7]helicenes 6. Supporting Information Supporting Information File 9: Experimental procedures, synthetic details, NMR spectra, chiral HPLC chromatograms, DFT and TD-DFT calculations. Supporting Information File 10

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• 86% yield. Mechanistic studies indicated that the pyrrolidine-based amide 73 reacts with iodonium salt 67 to form an imidate triflate intermediate U, which was isolated and characterized by NMR and HRMS. Subsequent hydrolysis via water attack affords the trifluoroethyl ester. This strategy also

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• nitroxides 2d–f, the samples of the radicals were reduced to the corresponding diamagnetic amines using a Zn/CF3COOH system in CD3OD at 63 °C, according to a literature protocol [23] and the 1H NMR spectra were recorded. The spectra showed similarity to those of previously described for radicals 2a–c [20

• sulfonate group, respectively [24]. The 1H NMR spectra of 3a,b,d–f (Zn/CF3COOH system in CD3OD) showed appearance of a singlet of methanesulfonate hydrogens in the region from 2.78 to 3.17 ppm. The NMR spectra were not recorded for 3c because of heavy resinification upon the sample preparation. The

• % yield). The IR spectra of the pyrazole derivatives 9a–c exhibit absorptions at 688–699 cm−1 and 763–770 cm−1, assigned to out-of-plane bending modes of the pyrazole ring [32]. The 1H NMR spectra of the reduction products of pyrazoles 9a–c were recorded after reduction using the Zn/CF3COOH system in

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• groups at the meta-position of the aromatic ring. In both cases, the endo-isomers predominated among the cycloadducts. However, using an N-arylmaleimide with an ortho-methoxy group, we obtained product 4p (26%) as diastereomeric mixture, and the exo-isomer became the major product. Notably, the 1H NMR

• configuration of their stereocenters, was determined using NMR spectroscopy and XRD analysis. endo-Isomers 4a–e exhibited the following characteristic signals in their 1H NMR spectra: multiplets in the range of δ 1.5–4.4 ppm were assigned to the protons of the pyrrolizidine ring system. The methyl singlets of

• were established using 1H,13C HSQC NMR spectroscopy. The chemical shift values, signal shapes, and spin–spin coupling constants are provided in Table S1 in Supporting Information File 1. The aromatic protons of compounds 4c–e appear in the downfield region of the spectrum. For product 4c, the aromatic

Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• early example was reported by Stille and co-worker in 1978, who elegantly demonstrated the formation of an η3-benzyl–palladium complex via oxidative addition of Pd(0) to a benzyl halide (Scheme 5C) [73]. Detailed stereochemical and NMR analyses revealed a temperature- and solvent-dependent equilibrium

A mild and atom-efficient four-component cascade strategy for the construction of biologically relevant 4-hydroxyquinolin-2(1H)-one derivatives

• Dmitrii A. Grishin,
• Kseniia I. Sharkovskaia,
• Ilya G. Kolmakov,
• Daria A. Ipatova,
• Rostislav A. Petrov,
• Nikolai D. Dagaev,
• Dmitry A. Skvortsov,
• Maria G. Khrenova,
• Valeriy V. Andreychev,
• Sergei A. Evteev,
• Yan A. Ivanenkov,
• Roman L. Antipin,
• Olga А. Dontsova and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2026, 22, 244–256, doi:10.3762/bjoc.22.18

• hours, the reaction mixture solidified, indicating malonamide formation which was followed by the addition of PPA and continuation of the reaction to afford products 2a–c in improved yields (77–83%). The resulting products showed negligible impurities as judged by 1H NMR and were identical to those

• , replacing alcohols with secondary amines (e.g., pyrrolidine) as the reaction medium did not lead to the desired amides. Experimental trials resulted in the formation of complex mixtures (as confirmed by 1H NMR), suggesting that the high reactivity of amines interferes with the selectivity of the cascade

Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• without further purification. Instruments and measurements Low-resolution mass spectra were recorded on a DSQ electron-impact (EI) mass spectrometer. High-resolution mass spectra (HRMS) were acquired on a Thermo MAT95XP instrument using fast atom bombardment (FAB) ionization. 1H and 13C NMR spectra were

• recorded on a Bruker Avance III 500HD superconducting NMR spectrometer using DMSO-d6 as the solvent and tetramethylsilane (TMS) as the internal standard. Single crystals suitable for X-ray diffraction analysis were grown from a dichloromethane/n-hexane solvent system; diffraction data were collected on a

• final pure product, 5-(3-(9H-carbazol-9-yl)phenyl)-2-(p-tolyl)isoindoline-1,3-dione (1), was obtained as a solid in a yield of 1.36 g (90%). 1H NMR (500 MHz, DMSO-d6) δ 8.34 (s, 1H), 8.31(d, 1H), 8.27 (d, 2H), 8.13 (s, 1H), 8.07–7.98 (m, 2H), 7.84 (t, 1H), 7.74 (d, 1H), 7.53–7.42 (m, 4H), 7.33 (s, 4H

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• solution. The isolated diaryl phosphates were brownish, likely due to the presence of trace impurities formed during the reaction; however, the NMR data revealed that few impurity peaks remained. All of these compounds are known, and the NMR spectral data were consistent with previously reported data for

• would be difficult. Furthermore, when 1-naphthol (1k) and 2-naphthol (1l) were used as substrates, the 31P NMR yields of the produced diesters were 45% (2k) and 29% (2l), respectively, and their isolation was difficult because of the presence of large amounts of naphthol-derived by-products. When the

• reactions were performed using alkyl alcohols, their behavior differed significantly from that of aromatic alcohols, and phosphate diesters were not obtained selectively. According to the results of the esterification time-course analysis via 31P NMR presented in Scheme 3 as well as in Figure 4 and Figure

Screwing the helical chirality through terminal peri-functionalization

• Devesh Chandra,
• Sachin and
• Upendra Sharma

Beilstein J. Org. Chem. 2026, 22, 205–212, doi:10.3762/bjoc.22.14

• phosphine oxide and the nitro-functionalized oxa[5]helicene. This ion-pairing interaction was also studied using NMR titration and Job’s plot analysis. The transition state depicted in Figure 3 was found to be most favorable providing the product with M-configuration. Looking ahead, these strategies may

Base-promoted deacylation of 2-acetyl-2,5-dihydrothiophenes and their oxygen-mediated hydroxylation

• Vladimir G. Ilkin,
• Margarita Likhacheva,
• Igor V. Trushkov,
• Tetyana V. Beryozkina,
• Vera S. Berseneva,
• Vladimir T. Abaev,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2026, 22, 192–204, doi:10.3762/bjoc.22.13

• : Full experimental details and characterization data of all new compounds. Supporting Information File 18: Copies of NMR spectra of all new compounds. Supporting Information File 19: CIF-file for compound 5g. Supporting Information File 20: CheckCIF-file for compound 5g. Funding We gratefully

Streptoquinolines A and B, new antibacterial meroterpenoids produced by Streptomyces sp. TMPU-A0679

• Akiho Yagi,
• Hitomi Tomura,
• Ami Konno and
• Ryuji Uchida

Beilstein J. Org. Chem. 2026, 22, 185–191, doi:10.3762/bjoc.22.12

• -resistant enterococci (VRE), two new meroterpenoids, streptoquinolines A (1) and B (2), were isolated from a culture of terrestrial Streptomyces sp. TMPU-A0679. The structures of 1 and 2 were elucidated based on spectroscopic analyses, including NMR and MS, and were found to consist of a drimane-type

• and 1620–1680 cm−1 indicated the presence of hydroxy and carbonyl groups, respectively. Streptoquinoline A (1): The molecular formula of 1 was elucidated as C28H35NO6 based on HRESIMS measurements. The 13C NMR spectrum (in DMSO-d6) showed 28 signals, which were classified into five methyl carbons

• , seven sp3 methylene carbons, two sp3 methine carbons, two sp2 methine carbons, two sp3 quaternary carbons, two oxygenated sp3 quaternary carbons, five sp2 quaternary carbons, and three carbonyl carbons from an analysis of the HMQC spectrum. The 1H NMR spectrum (in DMSO-d6) exhibited signals