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

• showed consumption of the educts after 30 min. Saturated aqueous solutions of Na2S2O3, Na2CO3 and NaCl (each 20 mL) were added together with ethyl acetate (50 mL) to generate two phases. After separation of the organic layer and subsequent extraction of the aqueous phase with ethyl acetate (3 × 20 mL

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

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

• Pharmacy, Shenzhen Technology University, Shenzhen 518118, China 10.3762/bjoc.22.31 Abstract The synthesis of racemic trans-taxifolin (trans-(±)-taxifolin) and its derivatives and subsequent chiral separation is the most prevalent chemical method to obtain enantiomerically pure taxifolin and its

• followed by chiral separation [16][19][20][21][22][23][24][25][26][27][28][29][30], which represents a relatively easily operated and controlled protocol. What is more important for this method is that it enables the synthesis of taxifolin derivatives, facilitating the exploration of their pharmacological

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

• chiral column at 25 °C (Figure 3) [17]. In sharp contrast to 1ab and 1ad, the HPLC analysis of 1ac showed a plateau between the peaks of the enantiomers at 25 °C, indicating that the interconversion of the enantiomers proceeds on the separation time scale (Figure 4) [18]. The interconversion plateau was

• effect of the phenyl group with the distorted alkene for a jump-rope rotation-type ring-flip (Figure 5) [10]. Enantioenriched samples of compounds 1ab and 1ad were obtained by HPLC separation using preparative scale chiral columns. We evaluated the stereochemical stability of 1ab and 1ad at 25 °C using

• oxacyclophene can be transformed into central chirality without loss of enantiomeric purity. For example, (S)-1ab obtained by chiral HPLC separation using an OJ-H column was treated with m-CPBA, in which (S)-1ab was smoothly consumed at 0 °C within 30 minutus to afford epoxide 8 in 61% yield (Scheme 4). HPLC

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

• simply washing of a solution of calixarene 47 in CDCl3 with water solved the issue. Indeed, the 1H NMR spectrum of the sample obtained after separation of the aqueous phase turned out to be easily interpretable (Figure 6d) and contained a set of signals from homodimer 472 similar to those in the spectrum

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

• ) relative to their oxaza[7]helicene analogues (<25 kcal/mol). After chiral HPLC separation, the enantiomers display mirror-image CD and strong solution CPL, with |glum| up to 2.6 × 10−3 and fluorescence brightness up to 30.75 M−1 cm−1. Keywords: chemoselectivity; chiroptical; circular dichroism

• ]. Chiroptical features The higher enantiomerization barriers of (P/M)-5a and (P/M)-5b enabled complete separation of their enantiomers by HPLC using a Daicel Chiralpak IA column (see Supporting Information File 1). Despite the rapid enantiomerization of (P/M)-6a and (P/M)-6b, we were able to separate the two

• analyses reveal that these oxaza[8]helicenes retain the aromatic character of the π‐framework while exhibiting significantly enhanced configurational stability compared to their oxaza[7] congeners, with enantiomerization barriers of up to ≈38 kcal mol−1. After chiral separation, the enantiomers display

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

• construct a twisted D–π–A molecular backbone. This molecular backbone achieves, on the one hand, frontier orbital spatial decoupling through donor–acceptor separation, reducing ΔEST and enabling TADF activation in amorphous environments. On the other hand, it retains the n→π* characteristics of the carbonyl

• 62.54°. These significant angles result in a distinctly twisted molecular framework, which plays a crucial role in spatially separating the donor (carbazole) and acceptor (phthalimide) segments of the molecule. This twisting and separation of the donor and acceptor parts of the molecule are critical for

• localized on the carbazole donor unit, while the lowest unoccupied molecular orbital (LUMO) is mainly concentrated on the phthalimide acceptor unit, as illustrated in Figure 1b and 1c. This significant separation of the HOMO and LUMO indicates a substantial frontier-orbital decoupling between the donor and

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

• greater charge separation in the excited state, which is more stabilized in polar solvents, typical of compounds that undergo an ICT upon excitation [86]. The use of EtOAc showed a hypochromic effect with a decrease in fluorescence emission. Similar results for chlorinated solvents (CH2Cl2, CHCl3) were

Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• product. They resolved racemic intermediate 27 by derivatization with (S)-1-(1-naphthyl)ethyl isocyanate, followed by separation of the resulting diastereomers via silica gel chromatography (Scheme 3). By converting diastereomer 32 to (−)-illisimonin A, the absolute configuration of the natural product

Ex-situ generation of gaseous nitriles in two-chamber glassware for facile haloacetimidate synthesis

• Nikolai B. Akselvoll,
• Jonas T. Larsen and
• Christian M. Pedersen

Beilstein J. Org. Chem. 2025, 21, 2465–2469, doi:10.3762/bjoc.21.188

• were obtained when using purification by “dry column vacuum chromatography” [28], which allowed separation of anomers. In the seminal paper by Schmidt [29] dichloroacetimidates were also synthesized. They were described as too unreactive to be viable alternatives to the trichloro analogs. The synthesis

The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions

• Ayhan Yıldırım and
• Mustafa Göker

Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184

• of hexane and dried in open air. The resulting mixture of isomers was subjected to direct NMR analysis, without any additional purification or separation steps. Versatile compounds via cycloaddition reactions. a) Radar view of the physical properties of methyl laurate. b) Oral toxicity values of

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

• length. These modifications enabled large-amplitude shuttling motions and created sufficient spatial separation, ensuring the macrocycle resides exclusively at one recognition site at a time [55]. Dithienylethene Dithienylethene photoswitches undergo an electrocyclic reaction, forming a closed-ring

• for applications in anion transport, extraction, and separation technologies. Conclusion and Perspectives The development of photoswitchable rotaxanes has mainly focused on controlling the position and movement of the macrocycle along the axle. Consequently, the vast majority of systems reported to

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

• –MS detection of the MPO-derived fragment and to achieve a separation of four candidate stereoisomers. To this end, methylation of commercially available methyl acetoacetate (2) and subsequent reduction of the ketone carbonyl group was carried out to prepare a mixture of four stereoisomers of methyl 3

• -hydroxy-2-methylbutanoate (3) [25][26]. We then explored LC–MS conditions for their separation. In our initial trial, the stereoisomeric mixture of 3 was successfully separated by preparative high performance liquid chromatography (HPLC) using a chiral column (data not shown). However, each stereoisomer

• 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

• % reference for clearance calculations. HPLC–MS analysis. The semi-quantitative determination of test compounds was carried out using a Waters Xevo G2-XS QToF mass spectrometer equipped with an electrospray ionization (ESI) source operating in positive ion mode. Chromatographic separation was performed on a

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

• hydroxy group at the α-position of the carboxyl group (Scheme 10) [38]. Yang and his team reported a metal-free catalytic system for the conversion of LA to PA (Scheme 10a). The use of NaI as catalyst and PA itself as solvent allowed to simplify the product separation process, giving yields up to 99

• from homogeneous catalysts such as mineral acids, organic acids, metal salts (with high availability and low costs) to heterogeneous ones such as zeolites, metal oxides, sulfonated polymers, carbon-based solid acids. The latter allow to overcome the problems of separation encountered with homogeneous

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

• aspera chaetominine B. Keywords: epoxidation; selective epimerization; stereodivergent synthesis; structural revision; tandem reaction; Introduction In contemporary organic chemistry, due to the widespread application of modern separation and analytical techniques, the structural elucidation and

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

• precipitation from non-polar solvents such as hexane and toluene did not lead to a complete separation of quinoxalinones 9 and Ph3PO. We attribute this to the ability of Ph3PO to form a strong hydrogen bond between the phosphoryl oxygen and a proton from the donor group of the second molecule [56][57][58], in

Measuring the stereogenic remoteness in non-central chirality: a stereocontrol connectivity index for asymmetric reactions

• Ivan Keng Wee On,
• Yu Kun Choo,
• Sambhav Baid and
• Ye Zhu

Beilstein J. Org. Chem. 2025, 21, 1995–2006, doi:10.3762/bjoc.21.155

• substituents. Intuitively, the intrinsic spatial separation among prochiral stereogenic elements, the reactive sites, and the stereochemical-defining substituents makes stereoinduction for non-central chirality using a chiral catalyst or reagent particularly challenging. However, a quantitative

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

• existence of inherent chirality for both MC1 and MC3, chiral resolutions using chiral high-performance liquid chromatography (HPLC) were performed. Due to insufficient solubility, MC3 failed in chiral separation via preparative chiral columns. Fortunately, two enantiomers of MC1 were successfully isolated

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

• cyclocondensation between these two components enabled by CPA catalysts yielded the inherently chiral DDDs 64 with good to high enantioselectivity (Scheme 18). While a number of reactions did not initially yield satisfactory enantioselectivity, facile phase separation during the workup process removed the less

• inherently chiral eight-membered azaheterocycles 72 with moderate to good enantioselectivity, along with the release of CO2 (Scheme 20). While the enantioselectivity using certain substrates was initially unsatisfactory, simple phase separation significantly enhanced the enantiopurity of the products by

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• is symmetry-forbidden, which reflects in a low intensity of this band, while the Z-isomer is bent, giving rise to a higher intensity nπ* band [48]. The distorted nature of both Z- and E-isomers of diazocine makes the nπ* transition symmetry-allowed: as a consequence, the absorbance and the separation

• soluble in water. For C- and S-diazocine, the absorption band separation of the two isomers is lower in polar solvents, resulting in worse PSS. In particular, for the S-diazocine it was found that the E-chair conformer was bathochromically shifted with increasing polarity of the solvent until completely

• indigos [67]. In general, electron-donating substituents red-shift the absorption and decrease the thermal half-life, and vice versa for the electron-withdrawing ones. Phenyl rings with electron-withdrawing p-substituents allow a better fine-tuning of the spectral separation between the two isomers (thus

Unique halogen–π association detected in single crystals of C–N atropisomeric N-(2-halophenyl)quinolin-2-one derivatives and the thione analogue

• Mai Uchibori,
• Nanami Murate,
• Kanako Shima,
• Tatsunori Sakagami,
• Ko Kanehisa,
• Gary James Richards,
• Akiko Hori and
• Osamu Kitagawa

Beilstein J. Org. Chem. 2025, 21, 1748–1756, doi:10.3762/bjoc.21.138

• ) observed in their single crystals. Results and Discussion Synthesis of quinoline-2-ones (thione), their enantiomer separation and rotational stability We focused on N-(2-halophenyl)quinolin-2-ones 1 and the thione analogue 2 as alternative substrates to verify chirality- and functional group-dependent

Continuous-flow-enabled intensification in nitration processes: a review of technological developments and practical applications over the past decade

• Feng Zhou,
• Chuansong Duanmu,
• Yanxing Li,
• Jin Li,
• Haiqing Xu,
• Pan Wang and
• Kai Zhu

Beilstein J. Org. Chem. 2025, 21, 1678–1699, doi:10.3762/bjoc.21.132

• back-pressure regulation within the continuous-flow reactor system becomes essential to maintain precise pressure control and prevent solvent vaporization. Continuous-flow nitration systems can be augmented with integrated process modules including in-line separation units (work-up zone), real-time

Chemical synthesis of glycan motifs from the antitumor agent PI-88 through an orthogonal one-pot glycosylation strategy

• Shaokang Yang,
• Xingchun Sun,
• Hanyingzi Fan and
• Guozhi Xiao

Beilstein J. Org. Chem. 2025, 21, 1587–1594, doi:10.3762/bjoc.21.122

• trials for post-resection hepatocellular carcinoma [26]. Interestingly, Ferro and co-workers revised the structure of PI-88 to I and II in 2017 via successful separation of oligosaccharide phosphate fractions by preparative ion-exchange chromatography (Scheme 1A) [27]. Besides the major components α(1→3

Thermodynamic equilibrium between locally excited and charge transfer states in perylene–phenothiazine dyads

• Issei Fukunaga,
• Shunsuke Kobashi,
• Yuki Nagai,
• Hiroki Horita,
• Hiromitsu Maeda and
• Yoichi Kobayashi

Beilstein J. Org. Chem. 2025, 21, 1577–1586, doi:10.3762/bjoc.21.121

• donor–acceptor dyads based on perylene (Pe) and phenothiazine (PTZ), in which triphenylamine (TPA) units and a phenyl spacer were introduced to modulate donor strength and spatial separation. Among the series, Pe–PTZ(TPA)2 exhibits a distinct thermal equilibrium between the locally excited (LE) state of

• the LE state of the PTZ moiety. In contrast, Pe-Ph–PTZ(TPA)2, in which the donor–acceptor distance is increased by a phenyl spacer, does not show clear equilibrium behavior. These results underscore the crucial role of excited-state structural relaxation in tuning photoinduced charge separation, and

• demonstrate that precise electronic and geometric design can enable controllable excited-state behavior in orthogonal molecular systems. Keywords: charge transfer; electron transfer; molecular dyad; transient absorption; Introduction Photoinduced electron transfer and charge separation are fundamental