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

• -toluenesulfonic acid at 80 °C in toluene afforded benzoxocin (7) as the only product. On the other hand, melifolione A (1) was completely decomposed under these conditions. Irradiation of 5 in methanol with UV-light (300 nm) for 3 days at room temperature gave melifolione B (2) with traces of melifolione A (1

• -trihydroxyacetophenone (3.7 g, 20 mmol), citral (3.2 g, 21 mmol) and pyridine (1.6 g, 20 mmol) was heated with stirring in a water bath at max. 60 °C for 8 h. After cooling to room temperature, the reaction mixture was diluted with 200 mL diethyl ether and extracted with 0.1 N H2SO4 (3 × 20 mL) to remove the pyridine

• tube and heated in a microwave apparatus (CEM, model DISCOVER, power 300 Watt) up to 140 °C for 20 minutes. After cooling to room temperature, the reaction mixture was dissolved in 200 mL diethyl ether. This solution was washed with 0.1 N NaOH (3 × 20 mL) and water (1 × 20 mL), dried over MgSO4

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

• ]heptadien-2-yl)-1,3,2-dioxaborolane (1e, 501 mg, 2.30 mmol), Pd(PPh3)4 (66.5 mg, 57.5 µmol, 5 mol %), THF (5.0 mL), and aq. NaOH (5.7 mmol, 2.7 M, 2.1 mL) was stirred at 80 °C for 16 h under anaerobic conditions [22]. After cooling the emulsion to room temperature, EtOAc (15 mL) was added and the organic

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

• calixarene tetraethylacetate [53]. In the original procedure, KOH was added at −5 °C, and the mixture was stirred for 5 hours at this temperature, followed by 5 days of stirring at room temperature. In our hands, both the addition of KOH and stirring were performed entirely at room temperature, and 1H NMR

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

• -dimethylaminobenzaldehyde 4-Dimethylaminobenzaldehyde (4.02 g, 26.9 mmol) was dissolved in 1,4-dioxane (52 mL) and NBS (5.01 g, 28.2 mmol) was added in small portions with stirring over 5 minutes. The reaction mixture was stirred at room temperature for 20 minutes then poured into 50 mL water. The mixture was diluted with

• solution of the test compound in DMSO or DMSO itself was added (1 µL), mixed by gently pipetting up and down, then incubated for seven minutes at room temperature. The glutaminase reaction was initiated by addition of 20 µL of a solution of glutamine (100 mM) and K2HPO4 (500 mM), then mixed by gently

• pipetting up and down and incubated at room temperature for seven minutes. The reactions were quenched by addition of cold 3 M HCl (10 µL). An aliquot (10 µL) of each quenched GAC reaction was added to 190 µL of a glutamate dehydrogenase reaction which consisted of a solution containing Tris-HCl (100 mM, pH

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

• give protected acetophenone 1 in an excellent yield of 78%. Next, the reaction conditions for the following α-bromination of acetophenone 1 to intermediate 2 were screened (Table S1, Supporting Information File 1). The treatment of compound 1 with CuBr2 in EtOAc at either room temperature or 60 °C

• all the Lewis acids screened, ZnCl2 was associated with best yield of 90%. Overall, the optimal conditions for the Darzens reaction involved treatment of 2 (1.0 equiv) with 3a (1.2 equiv) in MeCN at room temperature, using t-BuOLi (1.2 equiv) as the base and ZnCl2 (0.1 equiv) as Lewis acid catalyst

• mmol, 1.0 equiv), 3 (1.2 equiv), t-BuOLi (1.2 equiv) and ZnCl2 (10 mol %) in CH3CN (4.5 mL), stirred at room temperature for 4–6 h, N2 atmosphere. aZnCl2 was not added and the reaction time was 15 h. Yields are isolated yields. Synthesis of trans-(±)-taxifolin and its derivatives via the approach

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

• mmol) was added, and the reaction mixture was refluxed for 48 h. The reaction progress was monitored by TLC upon completion of the reaction. The mixture was allowed to cool to room temperature, and the solvent was removed under reduced pressure. The obtained residue was dissolved in chloroform and

• ethanol, and the reaction mixture was refluxed for 8 hours. The progress of the reaction was monitored by TLC. After completion, the reaction mixture was cooled to room temperature and the solvent was removed under reduced pressure. The resulting residue was dissolved in 30 mL of chloroform and washed

• completion, the reaction mixture was allowed to cool to room temperature, and the resulting precipitate was filtered, washed with ethanol, and dried to afford bromo compound 12 as an off-white powder (1.5 g, 66%). mp: 125 °C; 1H NMR (400 MHz, CDCl3) δ 8.64 (d, J = 7.2 Hz, 1H), 8.56 (d, J = 8.6 Hz, 1H), 8.39

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

• (to ≈1 M), reducing the content of acetic acid in the mixture (to 1 mol per mol of HNO3) and extending the room-temperature reaction time to 72 h. Yet, under these conditions, the desired calix[4]arene 11 was obtained in only 31% yield (Scheme 2), and further variations in reagent excess/concentration

• , the room-temperature nitration of the silylated p-tert-butylcalix[4]arene ether 8 using 2.5 equiv of HNO3 per calixarene aromatic unit resulted in di- or trinitrated macrocycles 12 and 14 as the major products, when ≈0.2 and ≈1 M nitric acid concentrations were used. Similarly, the wide-rim

• desilylated product in the case of calixarene 22) remained in the reaction mixtures even after their stirring at room temperature for 72 h. In the case of calixarene 22, heating of the mixture at 50 °C for 48 h was enough to complete the process and p-aminocalix[4]arene 25 having two propargyl groups at the

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

• Supporting Information File 1), we developed a one-pot electrochemical annulation between 3 and β-naphthol derivative 4. Using n-Bu4NPF6 as the electrolyte in CH2Cl2 at room temperature, this protocol furnished oxaza[8]helicenes 5 in good-to-moderate yields with >75% Faradaic efficiency, and no homo-coupling

• mol−1, respectively (Figure 3C and 3D), which leads to rapid enantiomerization within a few hours at room temperature and severely limits their applicability in chiroptical devices despite their favorable CD and CPL properties (vide infra). By comparison, the markedly higher (P/M) enantiomerization

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

• Taube reported the now famous pentaammineosmium(II) η2-benzene complex: the first system to yield kinetically stable η2-arene complexes that resist ligand exchange at room temperature in solution (Figure 5) [48]. This breakthrough opened the door to the isolation of such complexes and their subsequent

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

• a related protocol operating at room temperature using the ionic liquid [Bmim]HSO4 as a catalyst, expanding the scope to include aliphatic aldehydes [38]. Later, in 2017, Esmayeel Abbaspour-Gilandeh et al. reported a modified variant of this transformation under solvent-free heating, catalyzed by

• with α,β-unsaturated esters, such as (E)-3-(3,4-dimethoxyphenyl)acrylic acid esters 3 (see Supporting Information File 1) exemplified by compound 4. Different solvents and catalysts, both acidic and basic, were screened at room temperature, including refluxing in pyridine with piperidine, but the

• -unsaturated malonate 6 with 2a–c, various bases (sodium methoxide, triethylamine, potassium hydroxide) and solvents (ethanol, DMF, pyridine) were tested, mostly at room temperature, with an additional attempt at refluxing in ethanol/DMF. The desired malonate Michael adduct 7 (isolated and fully characterized

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

• analysis indicate that the HOMO and LUMO are localized on the carbazole and phthalimide fragments, respectively, affording a small singlet–triplet energy gap. In the solid state, compound 1 exhibits pronounced phase dependence: powder samples display room-temperature delayed emission with principal bands

• at 550/600 nm and a lifetime of ≈0.39 s that undergoes strong thermal quenching, diagnostic of room-temperature phosphorescence. In contrast, amorphous films show no RTP; their delayed component grows with temperature and shares the same peak position as the prompt emission, consistent with thermally

• states, intermolecular interactions enhance spin–orbit coupling and crystallinity suppresses nonradiative decay, thereby activating RTP. This work achieves an integrated “crystalline-state RTP–amorphous-state TADF” regulation within a single molecule. Keywords: imide; π–π stacking; room-temperature

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

• products (Scheme 1D) or the deacetylated products (Scheme 1E) have been developed. Results and Discussion Dihydrothiophene 1a was selected as a model substrate for our optimization study (Table 1). Initially, this compound was treated in ethanolic solution (2 mL) at room temperature in air for 1 h in the

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• stable in aqueous solutions at room temperature. Furthermore, we show that an intramolecular hydrogen bond is present in solution, which presumably is a key contributor to the high membrane permeability. Collectively, this physical-chemical profiling of 25CN-NBOH provides guidance to researchers with

• evaluation has not been conducted. The most widely used form of 1 is the corresponding HCl salt (1·HCl) that in our experience is a crystalline, nonhygroscopic and free-flowing solid, and aqueous solutions thereof appear stable for weeks at room temperature. To substantiate these qualitative observations, we

• for 1.5 hours at room temperature. Subsequently, the reaction was cooled in an ice bath before NaBH4 (192 mg, 5.08 mmol, 2.03 equiv) was added in four portions over 15 minutes. The reaction was left to stir at that temperature for an additional 20 minutes before leaving it at room temperature for 35

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• microcrystalline solid, was observed to be bench-stable for several months when stored in a sealed glass scintillation vial under ambient atmosphere at room temperature. Using the mild Kornblum oxidation, 4-bromo-2-nitrobenzyl bromide (6) was converted into the desired 4-bromo-2-nitrobenzaldehyde (4). As shown in

Circumventing Mukaiyama oxidation: selective S–O bond formation via sulfenamide–alcohol coupling

• Guoling Huang,
• Huarui Zhu,
• Shuting Zhou,
• Wanlin Zheng,
• Fangpeng Liang,
• Zhibo Zhao,
• Yifei Chen and
• Xunbo Lu

Beilstein J. Org. Chem. 2026, 22, 158–166, doi:10.3762/bjoc.22.9

• efficiency of the S(=N)–O bond formation. Under the standard conditions (Table 1, entries 1–10), 1a (0.15 mmol) was treated in MeOH (2a, 1.0 mL, ca. 24.6 mmol; ca. 160 equiv relative to 1a) at room temperature. To improve the compatibility of the protocol with solid or high molecular weight alcohols, we

• moiety. PIDA-mediated approach versus the present NBS-mediated approach to sulfinimidate esters. Substrate scope of sulfenamides derived from various thiophenols and thiols. Reaction conditions: sulfenamide 1 (0.15 mmol), NBS (1.2 equiv), NaHCO3 (1.5 equiv), MeOH (1.5 mL), room temperature, 30 min

• . Yields are of isolated products. Substrate scope of sulfenamides derived from various amides. Reaction conditions: sulfenamide 1 (0.15 mmol), NBS (1.2 equiv), NaHCO3 (1.5 equiv), MeOH (1.5 mL), room temperature, 30 min. Yields are of isolated products. Substrate scope of reactions between sulfenamides 1a

Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

• Kadri Kriis,
• Harry Martõnov,
• Annette Miller,
• Mia Peterson,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2026, 22, 151–157, doi:10.3762/bjoc.22.8

• stirred at room temperature until a suspension was formed (ca 5 min). After that, the reaction mixture was cooled to −20 °C. The malonic ester (0.171 mmol, 3.0 equiv) was added to the reaction vessel via syringe. The reaction was stirred at −20 °C for an appropriate time. The progress of the reaction was

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

• solutions (1.0 × 10−5 M) and 1 wt % PMMA matrices were acquired using a JASCO FP-8550 spectrometer at room temperature, at excitation wavelength of 300 nm (both solution and PMMA matrix). CPL spectra of CH2Cl2 solutions (1.0 × 10−5 M) and 1 wt % PMMA matrices were measured with a JASCO CPL-300

• spectrofluoropolarimeter at room temperature, at a scattering angle of 0° upon excitation with unpolarized, monochromated incident light. Absolute PLQYs of solutions and powder samples were determined using a JASCO FP-8550 spectrometer with an integrating sphere (JASCO ILF-533, diameter 96 mm) at an excitation wavelength

• (112 mg, 0.0962 mmol) and trimethylsilylacetylene (0.40 mL, 2.9 mmol) was added degassed solution of Et3N (2.6 mL, 19 mmol) and toluene (5.2 mL) by argon bubbling. The reaction mixture was refluxed at 90 °C for 21 hours. After cooling to room temperature, the reaction mixture was filtered through

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• aromatic rings (Scheme 4) [48]. Using [Rh(nbd)Cl]2 and Pd/C as catalysts, aromatic hydrocarbons with various functional groups can be hydrogenated at room temperature and 1 atmosphere of hydrogen, thus simplifying the reaction operation and cost. Hydrogenation of fused aromatic rings Hydrogenation of the

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• tryptophan. The resulting radical species underwent fast dimerization to furnish the desired dimer 61. This zirconocene-catalyzed dimerization proceeded smoothly under remarkably mild conditions at room temperature, suggesting broad applicability. Indeed, the reaction was shown to tolerate a wide substrate

• potential and stabilizing the radical pathway. The DFT calculations are shown in Scheme 13A. The activation barrier for the XAT process was calculated to be ΔG‡ = 8.0 kcal/mol, indicating that this process can proceed spontaneously around room temperature. Moreover, the transition state (TS1) suggested the

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

• transition states with an adjacent ester group, not to the stability of the main conformer. Conversely, the reactions with halogens and diazonium salts are immediate at room temperature and the α-selectivity, when observed, can be due to the stability of the main conformer. The transition from iodine to

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• of the desired products (Scheme 20B). The authors proposed that BTC functions by regenerating benzoyl chloride in situ from benzoic acid, thereby allowing the use of benzoyl chloride in catalytic quantities (Scheme 20C). Under similar conditions – benzoyl chloride (2.2 equiv), room temperature

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

• %) (Table 1, entry 10), with the formation of the cis,cis-bicycle 4acc as the predominant product (28%), while the proportion of hexahydrooxazolopyridones 5 was minimal (10%) compared to all other conditions. The highest content of hexahydrooxazolo[3,2-a]pyridin-5-one 5a was observed at room temperature in

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• MSCN/acid system. In comparison to ynamides [19] and alkynehydrazones [22], whose adducts cyclize with the involvement of nitrogen functional groups at elevated temperatures and extended reaction times, the reaction of CF3-substituted iminopropargyl alcohols occurred at room temperature within 15 min

• acetic acid. The reaction was carried out at room temperature and with vigorous stirring for 15 minutes. Next, the solvent was removed and the residue was purified using column chromatography (eluting with diethyl ether/hexane 1:8, then acetone/hexane 2:1 to give products 2 and 3. Procedure for oxidation

Recent advancements in the synthesis of Veratrum alkaloids

• Morwenna Mögel,
• David Berger and
• Philipp Heretsch

Beilstein J. Org. Chem. 2025, 21, 2657–2693, doi:10.3762/bjoc.21.206

• resulted in a hydroxy group, which was oxidized to furnish Nazarov precursor 54 in 52% yield. Key step of this sequence was the photoinduced excited-state Nazarov reaction, which involved irradiation of 54 in dichloroethane at 366 nm for 30 min at room temperature. Remarkably, this method had been

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

• amorphous character of the compounds exhibiting wide melting ranges (21b, 38d, 54f) were proven by XRPD measurements performed on a PANalytical Empyrean X-ray powder diffractometer at room temperature. Powder samples (without grinding) were placed between two Mylar foils in the sample holder at a reflection

• to 0–5 °C, and SnCl4 (47.28 g, 182 mmol, 21.2 mL) was added to the reaction mixture. The red suspension obtained was stirred at 0–5 °C for 1 h, then at room temperature for 2 h. It was poured onto a mixture of crushed ice (1500 g) and conc. hydrochloric acid (200 mL). It was stirred while warming to

• room temperature (ca 3 h). The crystalline product separated was filtered, washed with diluted hydrochloric acid (5%, 2 × 50 mL) and water (2 × 50 mL), then air-dried to give crude 7 (17.6 g of off-white solid). The two-phase filtrate was separated, the strongly acidic aqueous phase was washed with DCM