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

• crude materials containing 1 and 2 (23.5 mg). These materials were finally purified by preparative HPLC: column, Develosil C30-UG (Nomura Chemical Co., Ltd., Aichi, Japan), i.d. 10 × 250 mm; mobile phase, 55% MeCN aq. isocratic; detection, UV at 210 nm; flow rate, 3.0 mL /min. Under these conditions

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

• performed using a Gemini C18 column (150 × 4.60 mm, 5 µm) with a Gemini C18 precolumn (4 × 3.00 mm, Phenomenex, Torrance, CA, USA). Detection was performed at 241 nm, the column temperature was 30 °C, the injection volume was 10 µL, and the flow rate was 1 mL/min. The mobile phase consisted of acetonitrile

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

• asymmetric ones [23]. Organic dyes are also used as chemosensors, which provide economical, fast, and equipment-free analysis for the detection of environmental pollutants affecting the environment and human health [24][25]. Colorimetric detection of specific ions like cyanide, which is considered a highly

• dyes were examined, similar changes in their colors were observed under daylight like those in DMSO (Figure 4, insets). Additionally, the limit of detection (LOD) values of the compounds were calculated as 4.41 µM for 2a, 9.49 µM for 2b and 1.33 µM for 2c in DMSO/H2O binary solvent medium (Figure S15

• using the EFISH method, where μβ values were found between 300 × 10−48 esu and 1740 × 10−48 esu and the highest value observed was with 2b. Dyes also showed chemosensor properties for the selective detection of cyanide with colorimetric and optical responses in both organic and aqueous media. The

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

• were obtained using a MaXis mass spectrometer (Bruker Daltonik GmbH) equipped with an electrospray ionization source (4.5 eV) and a quadrupole time-of-flight analyzer (ESI–QTOF) in the positive ions detection mode, with methanol (0.1% FA [formic acid]) as solvent. Isolation of individual diastereomers

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 [79]. The colorimetric properties of rhodanine-derived compound 3n were used in the determination of silver [80] and gold [81] metals, and as a fluorescent sensor for detection of human serum albumin (HSA) [82]. Despite this, the TZD-derived compound 4n had its photophysical properties neglected

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

• the naphthalimide. Specifically, red fluorescence was observed when the merocyanine formed, and green fluorescence when the spiropyran was generated. Notably, this rotaxane was employed for the detection of sulfite, where the addition of sulfite led to the deactivation of FRET. This occurs due to a

• selective detection of sulfite for potential biological applications. Furthermore, the same group reported a photoswitchable [2]rotaxane containing a spiropyran stopper and a macrocycle armed with tetraphenylethylene for photopatterning applications (Figure 11) [20]. The macrocycle has been shown to shuttle

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

• incompatible with LC–MS detection, necessitating a relatively larger amount of sample for analysis. In contrast, a key advantage of our method is the use of a PNB group as the acyl moiety, which enables direct conversion to a C3-epimer via a Mitsunobu reaction, thereby streamlining the synthesis of the four

• stereoisomers. Additionally, the reversed-phase HPLC conditions without TFA in the mobile phase are compatible with LC–MS, enabling highly sensitive detection, and facilitating reliable stereochemical assignment using only a minimal amount (less than a microgram) of a natural product derivative. Conclusion In

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

• between 10 µM and 30 µM, and poor under 10 µM. Compounds with no value were under the detection limit. As a result, seven compounds had good solubilities: (E)-7c, (Z)-7c, 7d, 7e, 3b, 3c, and 3e. We also carried out a gastrointestinal parallel artificial membrane permeability assay (GI PAMPA). The

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

• methods for sensitive detection of endogenous PGD2 production and its stereoisomers are clinically important [5]. However, PGD2 is rapidly metabolized with a short half-life, making the identification and quantification of its downstream metabolites a promising and reliable diagnostic tool. Tricyclic

Rhodium-catalysed connective synthesis of diverse reactive probes bearing S(VI) electrophilic warheads

• Scott Rice,
• Julian Chesti,
• William R. T. Mosedale,
• Megan H. Wright,
• Stephen P. Marsden,
• Terry K. Smith and
• Adam Nelson

Beilstein J. Org. Chem. 2025, 21, 1924–1931, doi:10.3762/bjoc.21.150

• of each reaction was thus 200 μL, with final concentrations of 100 mM (for substrates), 500 mM (for co-substrates) and 1 mM (for catalysts). After 48 h, the outcome of the reactions was determined by analytical UPLC–MS with, additionally, evaporative light-scattering detection [22][23] to enable

• subsequently used. Panel B: yields, estimated by evaporative light scattering detection, of reactions involving combinations of substrates, co-substrates and catalysts (dash: <2% estimated yield). Highlighted combinations (green boxes) were selected for mass-directed purification. aMultiple intermolecular

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

• corresponding imines I and I′, as supported by the detection of imine I during GC–MS analysis. Both imines coordinate with the Lewis acid FeIII forming intermediates II and II′ with enhanced electrophilicity, respectively. Another equivalent of styrene (2a) attacks the electrophilic carbon, leading to the

On the aromaticity and photophysics of 1-arylbenzo[a]imidazo[5,1,2-cd]indolizines as bicolor fluorescent molecules for barium tagging in the study of double-beta decay of ¹³⁶Xe

• Eric Iván Velazco-Cabral,
• Fernando Auria-Luna,
• Juan Molina-Canteras,
• Miguel A. Vázquez,
• Iván Rivilla and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2025, 21, 1627–1638, doi:10.3762/bjoc.21.126

• Abstract In this paper, the behavior of a bicolor fluorescent indicator for the detection of barium cations formed by double-beta decay of 136Xe is analyzed by means of computational tools. Both DFT and TDDFT permit to understand the origin of the bicolor fluorescent signal emitted by 1-arylbenzo[a]imidazo

• ]. Within this context, from a chemical point of view, detection of ββ0ν radioactive decay of 136Xe requires an extremely sensitive detection of 136Ba2+. One promising candidate [6] would be a radiometric fluorescent sensor. With this idea in mind, we started a project aiming at designing, synthetizing and

Azobenzene protonation as a tool for temperature sensing

• Antti Siiskonen,
• Sami Vesamäki and
• Arri Priimagi

Beilstein J. Org. Chem. 2025, 21, 1528–1534, doi:10.3762/bjoc.21.115

• heavy metal detection [16][19] and humidity sensing [20]. The color changes can be either reversible or irreversible, depending on the mechanism of operation. Spectral tuning also enables switching with low-energy light, eliminating the need for potentially harmful UV irradiation [21]. Utilizing

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

• and KK (both below 5%) could be observed in amounts around the detection limit of optical spectroscopy, which finally should not lead to substantial spectral changes comparing to toluene. The absorption spectra, shown in Figure S10 (Supporting Information File 1), suggest a different story. The

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• and co-workers demonstrated that also BN heterocycles can be obtained using similar types of precursors (Scheme 23) [107]. Compound 179 was reacted with PhBCl2 to yield BN heterocycle 180 in 78% yield. Compound 180 exhibits high sensitivity for the visual detection of fluoride ions and undergoes an

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

Optimized synthesis of aroyl-S,N-ketene acetals by omission of solubilizing alcohol cosolvents

• Julius Krenzer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2025, 21, 1201–1206, doi:10.3762/bjoc.21.97

• presumed byproducts in the addition–elimination sequence in the presence of an excess of ethanol as a cosolvent are the ethyl ester formed by Einhorn acylation [7] of the acid chloride under the standard conditions and deep colored polar byproducts (according to TLC detection) that arise from self

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

• Shyam Sathyamoorthi,
• Appasaheb K. Nirpal,
• Dnyaneshwar A. Gorve and
• Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

• single regioisomer and diastereomer of B was formed (within the limits of 1H NMR detection), attesting to very selective reactivity. Here and in related projects, we found that many I(III) sources could generate a nitrenium ion, including iodosobenzene (PhIO) and iodomesitylene diacetate. However, unless

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

• Zhiyang Zhang,
• Jialei Hu,
• Hanfeng Ding,
• Li Zhang and
• Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

• single product, with no detection of 34 (Table 1, entry 11). This result presumably arises from the minimization of dipole–dipole repulsions between the carbonyl of the dienone moiety and the C14-OMe within the desired transition state (more details were discussed in our group’s previous work [29

Dicarboxylate recognition based on ultracycle hosts through cooperative hydrogen bonding and anion–π interactions

• Wen-Hui Mi,
• Teng-Yu Huang,
• Xu-Dong Wang,
• Yu-Fei Ao,
• Qi-Qiang Wang and
• De-Xian Wang

Beilstein J. Org. Chem. 2025, 21, 884–889, doi:10.3762/bjoc.21.72

• ]. Additionally, dicarboxylates like tartrate, adipate or citrate are widely used as food additives [23][24]. Furthermore, functional materials based on dicarboxylates are expected to play a significant role in future technologies [25]. Therefore, the recognition and detection of dicarboxylates are of great

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• fluorescent protein (GFP), has revolutionized genetics by providing highly accurate real-time detection of fusion proteins in vitro and in vivo [1]. Pioneering work on GFP-tagged proteins for real-time monitoring of gene expression was first reported by Chalfie and co-workers in 1994 [2]. For a long time

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• ) was used. MeCN/MeOH/H2O mixture with 50 mM formic acid and 25 mM diethylamine was used as eluent. A flow rate of 0.5 mL/min was applied and the detection of the respective compounds occurred at 280 nm. Data analysis was carried out with the EZChrom ELITE software (version 3.3.2 SP2, Agilent). Ni(II

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• antibodies in disease detection and treatment is that they are adorned with functional units (e.g., fluorophores, radionuclides, toxic payloads) that must be efficiently and selectively installed through compatible synthetic methods. Dozens of ADCs have been approved for clinical uses, and to date all are

Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• -UV system [column 2.1 × 50 mm, 1.7 μm, C18 Acquity UPLC BEH (Waters), solvent A: H2O + 0.1% formic acid; solvent B: ACN + 0.1% formic acid, gradient: 5% B for 0.5 min, increasing to 100% B in 19.5 min, maintaining 100% B for 5 min, RF = 0.6 mL/min, UV–vis detection 200–600 nm]. NMR spectra were

• ), solvent A: H2O + 0.1% formic acid; solvent B: acetonitrile (ACN) + 0.1% formic acid, gradient: 5% B for 0.5 min, increasing to 100% B in 20 min, maintaining isocratic conditions at 100% B for 10 min, flow = 0.6 mL/min, UV–vis detection 190–600 nm]. Preparative HPLC was achieved at room temperature on an

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• of 6 can evade detection if unaware of this issue. However, the amount of 6 can increase to as much as 20% when conducting the reaction at 0.1–0.3 M, the concentrations generally used for preparative work. Notably, because the SNAr reaction of 1 proceeded slowly, 4-(dimethylamino)thalidomide also