Efficient solid-phase synthesis and structural characterization of segetalins A–H, J and K

• Liangyu Liu,
• Wanqiu Lu,
• Quanping Guo and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2025, 21, 2612–2617, doi:10.3762/bjoc.21.202

• RP-HPLC. This optimized protocol afforded segetalins A–H, J and K (1–10) with 45% to 70% isolated yields (Figure 1). Structural characterization The synthetic compounds 1–10 were rigorously characterized to confirm their identity and purity (see Supporting Information File 1). High-resolution

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• for precise control over their structural, dynamic, and functional properties. By harnessing light as a non-invasive stimulus with high spatial and temporal resolution, these photoswitches allow for the modulation of the rotaxanes’ intra- and intermolecular interactions, optoelectronic properties, and

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• -diketones, the rigid lattice structure locks molecules into a specific conformation, limiting access to certain γ-hydrogens for abstraction and thus enhancing regioselectivity [42]. Enantiopure 87 was obtained by preparative chiral supercritical fluid chromatography (SFC) resolution of the racemate, while

A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures

• Rei Suo,
• Raku Irie,
• Hinako Nakayama,
• Yuta Ishimaru,
• Yuya Akama,
• Masato Oikawa and
• Shiro Itoi

Beilstein J. Org. Chem. 2025, 21, 2243–2249, doi:10.3762/bjoc.21.171

• the MPO moiety by LC–MS and demonstrate its application to the stereochemical assignment of capsulactone (1) at the microgram scale. The strategy involves the optical resolution of MPO derivatives, chemical degradation of 1, and the stereoselective synthesis of four diastereomers. Results and

• complete separation of the stereoisomers was not achieved, the corresponding peaks exhibited improved resolution compared to those of 4 (Figure S2, Supporting Information File 1). To further enhance separation, the p-nitrobenzoyl (PNB) ester 6 was prepared (Scheme 1B). After repeated trials with several

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

• using widely accepted strategies [46][47]. DMSO-d6 or CDCl3 were used as the solvents and tetramethylsilane (TMS) as the internal standard. Chemical shifts (δ) and coupling constants (J) are given in ppm and in Hz, respectively. High-resolution mass spectra were recorded on an Agilent 2750 GC/Q-TOF mass

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• 50% yield and 99% ee after kinetic resolution using Escherichia coli (Scheme 57) [189]. Other reactions: Yamamoto synthesized 6-hydroxy-2-(trifluoromethyl)-2H-pyran-3(6H)-ones from furfural via trifluoromethylation using the Ruppert–Prakash reagent (TMSCF3), followed by a photo-Achmatowicz reaction

Enantioselective desymmetrization strategy of prochiral 1,3-diols in natural product synthesis

• Lihua Wei,
• Rui Yang,
• Zhifeng Shi and
• Zhiqiang Ma

Beilstein J. Org. Chem. 2025, 21, 1932–1963, doi:10.3762/bjoc.21.151

• suppress potential intramolecular acyl migration. To further improve the optical purity of monoester 53, a Pseudomonas aeruginosa lipase-mediated kinetic resolution was performed with ethoxyvinyl butyrate 54, ultimately achieving monoester 53 with 97% ee in 60% yield and the diester 53a. With

• -worker described the asymmetric synthesis of (−)-rasfonin, harnessing an enantioselective enzymatic desymmetrization with lipase AK and an enzymatic oxidative kinetic resolution to install stereocenters [47]. The synthesis commenced with the preparation of fragment 100 from ethylene glycol (97) (Scheme

• functional group manipulations, alcohol 103 was subjected to enzymatic oxidative kinetic resolution with the bacterium Gluconobacter oxydans, producing alcohol 104 and acid 105. The alcohol 104 with the desired C9 stereocenter was then converted into fragment 106 in nine steps, while acid 105 was recycled to

Synthesis of N-doped chiral macrocycles by regioselective palladium-catalyzed arylation

• Shuhai Qiu and
• Junzhi Liu

Beilstein J. Org. Chem. 2025, 21, 1917–1923, doi:10.3762/bjoc.21.149

• yields (ΦF up to 0.69). Furthermore, enantiomeric resolution of inherent chiral MC1 was achieved using preparative chiral HPLC, enabling detailed investigation of its chiroptical behavior through circular dichroism and circularly polarized luminescence spectroscopy. Keywords: dihydroindolocarbazole

• , these macrocycles show blue to green emissions with high fluorescence quantum yields (ΦF up to 0.69). Owing to the existence of inherent chirality, two enantiomers of N-doped macrocycle MC1 were successfully isolated by chiral resolution, enabling detailed investigation of its chiroptical properties

• values up to 0.69. Remarkably, MC1 and MC3 are inherent chiral owing to their C1 symmetric structures. The enantiomers of MC1 were successfully isolated by chiral resolution, which indicate a gabs value of 1.1 × 10−3 and a glum value at the level of 10−4. Our work represents one of the rare examples of

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

Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• without the CPA catalyst. Notably, indolohelicenoid 23e could effectively be converted into the fully aromatic indolohelicene 24e under DDQ-mediated oxidative conditions without compromising the enantiopurity of the compound. Kinetic resolution stands as one of the most practical and efficient strategies

• ]. While CPAs have been extensively utilized in kinetic resolution of centrally chiral [26][27][28] and axially chiral compounds [29], their application in the kinetic resolution of helically chiral compounds remains largely unexplored. In 2024, Liu and co-workers developed an effective method for

• catalytic kinetic resolution of racemic helical polycyclic phenols through an organocatalyzed enantioselective dearomative amination reaction [30]. The racemic polycyclic phenol derivatives 25, which exist as single diastereomers featuring both central chirality and helical chirality, were readily prepared

Systematic pore lipophilization to enhance the efficiency of an amine-based MOF catalyst in the solvent-free Knoevenagel reaction

• Pricilla Matseketsa,
• Margret Kumbirayi Ruwimbo Pagare and
• Tendai Gadzikwa

Beilstein J. Org. Chem. 2025, 21, 1854–1863, doi:10.3762/bjoc.21.144

• Kansas State University for the acquisition of the NMR spectrometer (Grant CHE-1826982) used in this study. We thank the Ping Li Lab for high-resolution mass spectrometry, and the NIH for the grant (R01GM117259-01S1) which partially funded the purchase of the instrument.

Research progress on calixarene/pillararene-based controlled drug release systems

• Liu-Huan Yi,
• Jian Qin,
• Si-Ran Lu,
• Liu-Pan Yang,
• Li-Li Wang and
• Huan Yao

Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139

• Light-responsive controlled release Light is an ideal external stimulus due to its ease of use, low cost, and safety [110][111]. Its unique advantages include being easily turned on and off, providing high spatial and temporal resolution with precise control over irradiation wavelength and intensity

Convenient alternative synthesis of the Malassezia-derived virulence factor malassezione and related compounds

• Karu Ramesh and
• Stephen L. Bearne

Beilstein J. Org. Chem. 2025, 21, 1730–1736, doi:10.3762/bjoc.21.135

• reporting NMR spectral data are: bm, broad multiplet; bs, broad singlet; bt, broad triplet; d, doublet; dd, doublet of doublets; m, multiplet; q, quartet; s, singlet; and t, triplet. High-resolution (HR) electrospray ionization (ESI) mass spectra (MS) were collected using a Bruker microTOF Focus orthogonal

Structural analysis of stereoselective galactose pyruvylation toward the synthesis of bacterial capsular polysaccharides

• Tsun-Yi Chiang,
• Mei-Huei Lin,
• Chun-Wei Chang,
• Jinq-Chyi Lee and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2025, 21, 1671–1677, doi:10.3762/bjoc.21.131

• pattern aligns with existing literature and is corroborated by our X-ray analysis. High-resolution electrospray ionization mass spectrometry confirmed the molecular mass, showing spectral peaks aligning with the calculated mass ([M + Na]+ calcd for C72H78N4O23Na, 1389.4949; found, 1389.4943). Conclusion

Catalytic asymmetric reactions of isocyanides for constructing non-central chirality

• Jia-Yu Liao

Beilstein J. Org. Chem. 2025, 21, 1648–1660, doi:10.3762/bjoc.21.129

• unsymmetrical diisocyanide was used, the initial isocyanide insertion was found to be non-regioselective, delivering a 1:1 mixture of regioisomers (17c and 17c’). Intriguingly, 17a could act as a chiral acylating reagent, applying in the kinetic resolution of racemic primary amines rac-18. Additionally, after

• reaction between alkene 43 and 2,2′-dienone 44. The corresponding spirooxindole 45 was obtained in >19:1 dr, 63% yield, and 89% ee. Dynamic kinetic resolution of configurationally labile bridged biaryls The catalytic asymmetric dynamic kinetic resolution (DKR) of configurationally labile bridged biaryls

• Groebke–Blackburn–Bienaymé reaction. Construction of axially chiral 3-arylpyrroles via de novo pyrrole formation. Synthesis of atropoisomeric 3-arylpyrroles via central-to-axial chirality transfer. Dynamic kinetic resolution of bridged biaryls with α-acidic isocyanides. Desymmetrization of prochiral

Synthesis of optically active folded cyclic dimers and trimers

• Ena Kumamoto,
• Kana Ogawa,
• Kazunori Okamoto and
• Yasuhiro Morisaki

Beilstein J. Org. Chem. 2025, 21, 1603–1612, doi:10.3762/bjoc.21.124

• LC918R (JAIGEL 1H and 2H gel-permeation columns) using CH2Cl2 as an eluent. Recyclable chiral chromatography (HPLC) was carried out on a YMC LC Forte/R (Chiralpak® IA column). High-resolution mass spectra (HRMS) was obtained on a Bruker Daltonics microTOF II spectrometer (APCI) by using sodium formate

Synthesis of an aza[5]helicene-incorporated macrocyclic heteroarene via oxidation of an o-phenylene-pyrrole-thiophene icosamer

• Yusuke Matsuo,
• Aoi Nakagawa,
• Shu Seki and
• Takayuki Tanaka

Beilstein J. Org. Chem. 2025, 21, 1561–1567, doi:10.3762/bjoc.21.119

• , along with decamer 3 (30%). High-resolution atmospheric-pressure-chemical-ionization time-of-flight mass-spectrometry (HR-APCI-TOF-MS) showed a molecular ion peak for 4 at m/z = 1479.4320 (calcd for C100H66N6S4, m/z = 1479.4305). The 1H NMR spectrum of 4 in acetone-d6 exhibited two NH signals at 9.07

Highly distinguishable isomeric states of a tripodal arylazopyrazole derivative on graphite through electron/hole-induced switching at ambient conditions

• Himani Malik,
• Sudha Devi,
• Debapriya Gupta,
• Ankit Kumar Gaur,
• Sugumar Venkataramani and
• Thiruvancheril G. Gopakumar

Beilstein J. Org. Chem. 2025, 21, 1496–1507, doi:10.3762/bjoc.21.112

• -resolution images, and an example is shown in Figure 2d. The resonances in the 2D-FFT are originated from the moiré pattern of the super-lattice. Two distinct orientations are visible in the 2D-FFT. The 3-fold orientation of islands suggests that the molecular lattices are oriented with respect to the

• lattice is not a commensurate lattice with respect to graphite [33][34][35]. A high-resolution AFM phase image of a few islands in 1D phase is shown in Figure 2c. Molecular domains reveal line-like features within the domains and extend through the length of the islands. Adjacent line-like features are

• covered by the 2D phase. Interestingly, high-resolution images revealed no line-like features due to the moiré pattern within the islands in the 2D phase. As suggested earlier, the moiré pattern is typical for incommensurate structures. Thus, we propose that in the 2D phase, the molecules organize

Wittig reaction of cyclobisbiphenylenecarbonyl

• Taito Moribe,
• Junichiro Hirano,
• Hideaki Takano,
• Hiroshi Shinokubo and
• Norihito Fukui

Beilstein J. Org. Chem. 2025, 21, 1454–1461, doi:10.3762/bjoc.21.107

• temperature-dependent 1H NMR measurements. The relatively preferable formation of bathtub conformation is attributable to the destabilization of the figure-eight structures by the intramolecular steric repulsion between the exo-methylene units and neighboring benzene rings. Resolution The resolution of rac-3

• ) and (Ra,Ra), respectively (see Supporting Information File 1, Figures S1 and S2). The resolution of (CH2CH2O)-substituted DBC derivative 4 at ambient temperature was examined using DAICEL CHIRALPAK IA–IE (eluent: CH2Cl2/hexane and 2-propanol/hexane). However, the resolution was unsuccessful due to the

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• chiroptical retention upon nitrogen incorporation. Qian’s group developed a series of azahelicenes 15a–d through Bischler–Napieralski cyclization [28]. Notably, compound 15b displayed a high interconversion barrier of 36.0 kcal mol−1, enabling enantiomeric resolution. All compounds exhibited visible-range

Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds

• Lidia Zaharieva,
• Vera Deneva,
• Fadhil S. Kamounah,
• Nikolay Vassilev,
• Ivan Angelov,
• Michael Pittelkow and
• Liudmil Antonov

Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105

• precoated TLC plates (0.2 mm thick). The identity of all compounds was confirmed employing various spectroscopic techniques including NMR and HRMS–ESI high-resolution mass spectrometry. The 1H and 13C NMR spectra were recorded in CDCl3 or DMSO-d6 at 25 °C on a Bruker Ultrashield Plus 500 spectrometer using

• 125 MHz for 13C NMR in CD2Cl2 and 600 MHz for 1H NMR and 151 MHz for 13C NMR in CDCl3 and CD3CN. ATR-FTIR spectra of the compounds were recorded on a Bruker Tensor 27 FTIR spectrophotometer in the range of 4400–600 cm−1 with a resolution of 2 cm−1 at room temperature. The external reflection diamond

• ) spectrofluorometer in the range 200–800 nm with a resolution of 0.5 nm and double-grating monochromators using as excitation wavelength a value near the absorption maxima of the compounds with concentrations of ≈10−6 mol L−1. The irradiation experiments were performed with an experimental setup designed and

Reactions of acryl thioamides with iminoiodinanes as a one-step synthesis of N-sulfonyl-2,3-dihydro-1,2-thiazoles

• Vladimir G. Ilkin,
• Pavel S. Silaichev,
• Valeriy O. Filimonov,
• Tetyana V. Beryozkina,
• Margarita D. Likhacheva,
• Pavel A. Slepukhin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2025, 21, 1397–1403, doi:10.3762/bjoc.21.104

• larger or even commercial scale. The structures of compounds 3 were confirmed by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry. The 1H NMR spectra are characterized by signals from protons of the aromatic rings in the range of 8.08–7.32 ppm, singlets for the proton at the C-3 position

N-Salicyl-amino acid derivatives with antiparasitic activity from Pseudomonas sp. UIAU-6B

• Joy E. Rajakulendran,
• Emmanuel Tope Oluwabusola,
• Michela Cerone,
• Terry K. Smith,
• Olusoji O. Adebisi,
• Adefolalu Adedotun,
• Gagan Preet,
• Sylvia Soldatou,
• Hai Deng,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2025, 21, 1388–1396, doi:10.3762/bjoc.21.103

• new natural products, pseudomonins D–G (1–4) isolated alongside other three known compounds, pseudomonine (5), pseudomonin B (6) and salicylic acid (7), were elucidated based on high-resolution mass spectrometry, 1D and 2D NMR analyses. The absolute configurations of the threonine residue in compounds

• extract. The chemical dereplication of the crude extract by high-resolution electrospray ionisation mass spectrometry (HRMS) analysis and online natural product databases (Reaxys [19], AntiBase 2017 [20] and Natural Product Atlas [21]) revealed the presence of unknown molecular ions in addition to the

• unsaturation, calcd. for C11H12NO5, 238.0721) of 1 was established from negative mode high-resolution electrospray ionisation (HRESI) mass spectrum data which showed a deprotonated molecular ion, [M − H]−1 at m/z 238.0723. The complete analysis of 1D and 2D NMR spectra (see Table 1 and Supporting Information

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

• Kelsey Plasse,
• Valerie Wright,
• Guoshu Xie,
• R. Bernadett Vlocskó,
• Alexander Lazarev and
• Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

• , known entities and they were identified based on their high-resolution mass spectra. The mass spectrometric identification and purity determination of the products have been carried out by using an Agilent 7250 GC-QTOF mass spectrometer operated in electron impact ionization (EI, 70 eV) mode using a 30m

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101