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

• ], diammonium phosphate (DAP) [43], and tetrabutylammonium bromide (TBAB) [44]. Organic bases like morpholine [45], triethylamine [46], ethanolamine, and piperidine [47] and heterogeneous catalysts from Cu [48], Ti [49], and Zn [50] metal compounds have also been used. Common solvents are ethanol [51], toluene

Silica gel with covalently attached bambusuril macrocycle for dicyanoaurate sorption from water

• Michaela Šusterová and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2025, 21, 2604–2611, doi:10.3762/bjoc.21.201

• phosphate buffer (pH 7.1) was chosen to test the materials’ stability in an aqueous environment. 1H NMR measurements showed that neither material released BU into organic solvents in the absence of anions. This was unexpected for SG-BnBU, since BnBU is readily soluble in chloroform and dichloromethane and

• presence of salt showing it is suitable for applications in an aqueous environment. SG-BU1 proved to be stable in chloroform, dichloromethane, and methanol even after addition of TBACl or NaCl, respectively. We did not detect any release of BU1 from SG-BU1 in aqueous phosphate buffer by NMR, but we

Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA

• Grant D. Walby,
• Brandon R. Tessier,
• Tristan L. Mabee,
• Jennah M. Hoke,
• Hallie M. Bleam,
• Angelina Giglio-Tos,
• Emily E. Harding,
• Vladislavs Baskevics,
• Martins Katkevics,
• Eriks Rozners and
• James A. MacKay

Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193

• recognition of DNA via triplex formation [17][18]. In this approach, PNA has several advantages compared to other TFOs. PNA was originally designed to be a charge neutral oligonucleotide that reduces electrostatic repulsions with the anionic phosphate backbone of DNA. Additionally, PNA is stable to nucleases

• stabilizing H-bond but rather formed a hydrogen bond with the U in the U–A base pair (ca. 2.2 Å, Figure 7B). This interaction resulted in pushing the entire residue towards the RNA backbone where the Io base could further bind to a phosphate which likely explains why Db2 shows the lowest triplex stability of

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

• achieved ortho- and para-selective cyclization of methoxyamide-functionalized alkynes via ligand-controlled steric and electronic modifications (Scheme 17) [25]. When a flexible electron-deficient phosphate ligand L1 was utilized, the Au(I)-catalyzed cyclization of substrates 78 resulted in the formation

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

• KGaA (Darmstadt, Germany). For gastrointestinal permeability studies, ʟ-α-phosphatidylcholine and cholesterol were purchased from Sigma-Aldrich (Merck KGaA, Darmstadt, Germany). Phosphate buffered saline (0.01 M, pH 6.5 and 7.4) was prepared from pre-mixed PBS powder also sold by Sigma-Aldrich (Merck

• microsome (HLM) fractions were thawed on ice and diluted in 0.05 M potassium phosphate buffer (pH 7.4) to a final protein concentration of 1.25 mg/mL. Test compounds were dissolved in DMSO to create stock solutions of 5 mM. The drug concentration in the final assays was 10 μM. The assay was performed in

• phosphate buffer for the “without cofactors” control. Aliquots (100 µL) were taken at zero time and at pre-defined time points of 30 and 60 minutes and quenched with an equal volume of cold acetonitrile. The samples were centrifuged at 2600 RCF for 10 minutes to pellet proteins. Supernatants were

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

• ][80][81]. Keto acetals have been observed as by-products, such as in the work reported by Gupta investigating the acid-catalyzed reactions of DHA with various alcohols (Scheme 17) [82]. Colbran and colleagues reported the conversion of DHA to dihydroxyacetone phosphate in four steps in 27% overall

• yield [83]. In their synthesis the cyclic acetal (2,5-diethoxy-1,4-dioxane-2,5-diyl)dimethanol or its dimethoxy analog was esterified with diphenyl phosphorochloridate in pyridine to give (2,5-diethoxy-1,4-dioxane-2,5-diyl)bis(methylene) tetraphenyl bis(phosphate). Subsequent removal of the phenyl

• groups through hydrogenolysis, neutralization with cyclohexylamine and treatment with ion-exchange resin led to dihydroxyacetone phosphate. This 4-step method was more efficient than the previously reported dismutation of fructose-1,6-diphosphate [84] and 3-chloro-1,3-propanediol [85] which required more

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• ) shows a singlet at +32 ppm; for diglycidyl methylphosphate (2) and triglycidyl phosphate (3) also a singlet in the region 0–1 ppm is observed, despite the presence of a chiral carbon atom in the oxirane fragment. In the 1H NMR spectra of esters 1–3 the characteristic signals of the oxirane fragment at

• , PC-3, and MCF7 cell lines, respectively. Similarly, diglycidyl methylphosphate (2) achieved 50% inhibition at concentrations of 398 ± 33 μM, 300 ± 21 μM, and 128 ± 10 μM. Triglycidyl phosphate (3) exhibited IC50 values of 254 ± 19 μM for HSF, 257 ± 20 μM for PC-3, and 182 ± 14 μM for MCF7 cells

• . Among the tested compounds, triglycidyl phosphate (3) demonstrated the highest overall cytotoxicity against HSF and PC-3 cell lines, while diglycidyl methylphosphate (2) showed the greatest potency toward MCF7 breast cancer cells. Although the IC50 values for compounds 1 and 2 were somewhat higher in

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

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

• ease of modification [42]. Among these, CAs and PAs are representative aromatic macrocycles. They can be made water-soluble and exhibit good biocompatibility through carboxyl or phosphate group modification, showing great potential in biomedical carrier applications. Compared with other artificial

• molecules and high-selectivity binding in drug-controlled release. Many calix/pillar[n]arene hosts are soluble in water, particularly macrocycles that are modified with carboxyl and phosphate groups. Moreover, their amphiphilic modification ability allows easy self-assembly into functional materials like

• supramolecular complexes, based on their amphiphilic nature, have the ability to form higher-order aggregates in weakly alkaline phosphate-buffered saline (PBS). The resulting supramolecular nanoparticles exhibited stability under physiological conditions. The cumulative release of DOX reached nearly 100% within

Approaches to stereoselective 1,1'-glycosylation

• Daniele Zucchetta and
• Alla Zamyatina

Beilstein J. Org. Chem. 2025, 21, 1700–1718, doi:10.3762/bjoc.21.133

• -withdrawing substituents leads to improved yields and stereoselectivities. Accordingly, the combination of GlcN-derived lactol 80 and the 2N-Troc-protected GlcN imidate donor 79, both bearing multiple bulky substituents such as dibenzyl phosphate, TBDMS, and Troc protecting groups, resulted in a complex

• (Scheme 8). Enhancing the acceptor reactivity by introducing a benzyl group at the C4–OH and relocating the phosphate group from position 4 to 6, as in GlcN-lactol 88, resulted in a decreased yield of the β,α-1,1'-linked product 89. Despite the high prevalence of the α-anomer in the acceptors 86 and 88 (α

• an electron-withdrawing ‘disarming’ substituent, as exemplified by the 3-O-Alloc-protected lactol acceptor 119 [95]. The disarming effect of the 4-O-phosphate group in the PTFA donor 79 had to be counterbalanced by the electron-donating 3-O-TBDMS group, since alternative glycosyl donors bearing

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

• )-branching. The C6–OH group in 5 was protected as TBDPS group, which could be selectively replaced by the destined phosphate residue. One-pot synthesis of glycans 1 and 2 We commenced with the synthesis of monophosphorylated trisaccharide 1 (Scheme 2A). Glycosylation of mannosyl PTFAI 5 (1.2 equiv) with 3-OH

• yield via the switch of the TBDPS group with the phosphate group. First global deprotection of Bn and Cbz groups in 18 with Pd(OH)2/C, followed by saponifications of all Bz groups with 1 M NaOH provided the desired monophosphorylated pentasaccharide 3 in 56% overall yield, which is the major glycan

Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins

• Juliana V. Petrova,
• Varvara T. Tkachenko,
• Victor A. Tafeenko,
• Anna S. Pestretsova,
• Vadim S. Pokrovsky,
• Maxim E. Kukushkin and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118

• compounds in two-fold serial (50–100 μM) dilutions. Only DMSO + PBS (phosphate-buffered saline) was used as a control, since the studied compounds were soluble only in DMSO. Cell viability was measured using the standard MTT test [42]. Absorbance was measured at 540 nm using a Multiskan™ FC microplate

Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation

• Zhihua Liu,
• Ya-Zhi Chen,
• Ji Wang,
• Qingling Nie,
• Wei Zhao and
• Biao Wu

Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68

• L as an anion receptor to extract cesium salts (chloride, nitrate, carbonate, sulfate, and phosphate) from the solid phase into chloroform. Remarkably, Cs3PO4 exhibits the highest extraction efficiency, driven by strong cooperative interactions involving ion-dipole coordination between Cs+ and

• that a tripodal hexaurea receptor L (Figure 1b) could selectively and reversibly extract sulfate and phosphate anions from water into organic phase (under pH control) [30][31][32][33]. Single crystal structures of the receptor–K2SO4 complex in the presence of 18-crown-6 clearly displayed ion-dipole

• hexaurea receptor, 18-crown-6 and Cs+ as cation were selected as model system, with the counter anion being varied from chloride, nitrate, carbonate, sulfate to phosphate. Solid–liquid extraction experiments and single-crystal structures demonstrated that the cooperative interactions (ion-dipole and ion

New advances in asymmetric organocatalysis II

• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 766–769, doi:10.3762/bjoc.21.60

• transformation was catalyzed by a calcium complex of BINOL phosphate [29]. As can be seen from the summary above, the articles in this thematic issue cover a diverse array of topics in contemporary asymmetric organocatalysis. Moreover, they also reflect the diversity of our scientific community, as researchers

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• hydrocyanation of hydrazones, catalyzed by a calcium–BINOL phosphate complex, has been studied for the first time both experimentally and computationally with DFT methods. A full catalytic cycle for the enantioselective synthesis of α-hydrazinonitriles is proposed based on insights gained from DFT calculations

• enantioselectivity achieved with the calcium catalyst remains modest, mainly due to competing pathways for the Z- and E-hydrazone isomers leading to opposite enantiomers. The experimental results confirm these computational proposals. Keywords: asymmetric synthesis; calcium–BINOL phosphate catalysis; hydrocyanation

• in elucidating the mechanism by which these bifunctional compounds act as powerful catalysts [21][22][23][24][25][26][27][28][29]. Since Ishihara disclosed the crucial role of calcium in many purportedly purely organocatalytic BINOL phosphate-catalyzed reactions [30][31], several asymmetric synthesis

Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

• -association in phosphate-buffered saline (PBS) which might impinge on guest binding and complicate the determination of C1·guest binding constants. For this purpose, we performed dilution experiments monitored by 1H NMR spectroscopy. We prepared a series of NMR samples of C1 in D2O (from 4 mM to 125 μM) and

• achieved by changing the concentration of host in the ITC cell [76][77][78]. Figure 7a presents the thermogram recorded when a solution of C1 (100 μM) in phosphate-buffered saline (PBS) in the ITC cell was titrated with a solution of CHDA (1 mM) from the ITC injection syringe. The DP versus time data in

• JEOL AccuTOF electrospray instrument. ITC data was collected on a Malvern Microcal PEAQ-ITC instrument with a cell volume of 200 µL and an injection syringe with a capacity of 40 μL. For ITC experiments, the host and guest solutions were prepared in a 20 mM phosphate-buffered water (pH 7.4). The sample

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• electrophiles 11. Enantioselective hydroallylation and allylboration of styrenes A significant advance in the CuH-catalyzed enantioselective allylic substitution was reported by Buchwald and co-workers in 2016, who demonstrated the first successful hydroallylation of vinylarenes 30 using allylic phosphate

• optimization revealed LiOt-Bu and diphenyl phosphate as the optimal metal alkoxide and leaving group, delivering the desired product 32 in high yield and high enantioselectivity at room temperature with only 2 mol % catalyst loading. The scope of this transformation proved to be remarkably broad. In addition

• , providing rapid access to highly enantioenriched organometallic and organosilicon compounds. Mechanistic studies using a deuterium-labeled allylic phosphate revealed that the C–C-bond formation occurs through an SN2'-like process, with attack of the organocopper species at the 3-position of the allylic

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• the formation of 1,2-trans stereodirected glycosyl products 77 when the donor was suitably activated using BSP and Tf2O [139]. The role of the 2,2-dimethyltrimethylene (DMTM) phosphate group at the participating C-2 protection was analysed wherein the NMR studies showed no isolation of the

• by the participation of the phosphate group by reverse anomeric effect. However, according to the authors, the phosphate groups acting as a neighbouring participating group forming the corresponding oxocarbenium ion intermediate 73 (path B, Scheme 13) seemed to be more plausible. Non-ester

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C–F bond activation

• Takeshi Fujita,
• Haruna Yabuki,
• Ryutaro Morioka,
• Kohei Fuchibe and
• Junji Ichikawa

Beilstein J. Org. Chem. 2025, 21, 146–154, doi:10.3762/bjoc.21.8

• at the 4-position (2d) also produced high yields (94–98%). For arylboronic acid 2f, which has a methoxy group at the 4-position, the use of potassium phosphate as a base resulted in a 94% yield of 3bf. For arylboronic acid 2g, which features a strongly electron-withdrawing trifluoromethyl group, we

• optimized the coupling reaction using potassium phosphate as a base and increasing the nickel catalyst loading to 20 mol %, achieving a yield of 78% for the desired product 3bg. When 2-naphthylboronic acid (2i) was employed, its solubility was enhanced using a mixed solvent system of toluene, methanol, and

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• , forming a new C(sp3)–C(sp3) bond. The reaction can be performed in a phosphate-buffered saline (PBS) solution and shows post-functionalization prospects through pathways involving classical peptide chemistry. Keywords: dehydroalanine; Giese-type reaction; hydroalkylation; photocatalysis; water

• observed in CH3CN (58% yield, 100% conv.; Table 1, entry 3). These conditions were further refined by adding of phosphate-buffered saline and decreasing the amount of (TMS)3SiH to 1.1 equiv, as no further increase in yield was noticed during the optimization. Similar to the reaction in deionized water, all

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• of action (MOA) (e.g., membrane lysis and depolarization) [30][34] and specific MOA (e.g., dysregulation of ClpP protease [33], inhibition of topoisomerase I/II [36][68], blocking lipid II transport by flippase [29], sequestration of cell wall biosynthetic intermediate C55-(di)phosphate, etc.) [35

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• , [3]rotaxane diol 10 was used as the initiator of the controlled ring-opening polymerization (ROP) of ε-caprolactone in the presence of a diphenyl phosphate catalyst to introduce the polyester main chain into the rotaxane framework; the successive end-capping reactions yielded macromolecular [3

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• chemistry on the histone H2A protein. The protein was demonstrated as the T120C mutant via site-directed mutagenesis in Escherichia coli and decontaminated by HPLC. A notable reconciliation was changing the aqueous buffer from HEPES to phosphate owing to side-product generation during the arylation in HEPES

• . The reaction of H2A with the diaryliodonium salt in phosphate buffer resulted in the expected arylated conjugate in an hour with a maximum of 98% conversion, yielding sulfur arylated product in 54% isolated yield after purification by HPLC. Additionally, the functionalization of the ketone with a

Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions

• Hayato Takagi,
• Çetin Çelik,
• Ryosuke Fukuda,
• Qi Guo,
• Tomohiro Higashino,
• Hiroshi Imahori,
• Yoko Yamakoshi and
• Tatsuya Murakami

Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231

• samples dispersed in phosphate-buffered saline (PBS(–)). UV–vis absorption spectra of liposomes (1 mM phospholipid) with C60 (a) or a cationic derivative of C60 (catC60) (b) added at various molar equivalents (mol equiv) to phospholipid. The equivalent of C60 added in C60-loaded liposomes (C60-lip) was

• dotted lines. Liposome samples were dispersed in phosphate-buffered saline (PBS(–)). Fluorescence spectra of 1-pyrenebutyric acid (PyBA) in cationic derivative of C60 (catC60)-loaded liposomes (catC60-lip, 1 mM phospholipid) containing catC60 at various concentrations. (a) Effect of catC60 in liposomes

• on the fluorescence intensity of PyBA, with concentrations of catC60 at 0, 5.4, 54 µM, and PyBA at 50 µM. (b) Fluorescence spectra of catC60-lip with 0 and 54 µM catC60, treated with 50 µM PyBA, after addition of methanol. Liposome samples were dispersed in phosphate-buffered saline (PBS

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• cyanoarenes, nitroarenes, quinolines, and pyridines using a proton-exchange membrane (PEM) reactor was developed. Cyanoarenes were then reduced to the corresponding benzylamines at room temperature in the presence of ethyl phosphate. The reduction of nitroarenes proceeded at room temperature, and a variety of

• . Therefore, it was necessary to perform the reaction under anhydrous conditions. Hence, we used ethyl phosphate (mono- and di-mixture) (pKa = 1.42), which reacts easily under anhydrous conditions. As expected, the generation of 3a was suppressed and 2a was selectively obtained (Table 2, entry 5). With the

• reactions. For instance, the addition of ethyl phosphate is essential for the electroreduction of cyanoarenes. The generation of dibenzylamine was suppressed and benzylamines were obtained efficiently. The PEM system was effective in reducing nitroarenes. Several functional groups were tolerated under these