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

• antitumor agent PI-88 (muparfostat), which retards tumor growth via inhibiting angiogenesis in two ways: 1) interaction with pro-angiogenic growth factors such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) and 2) by prevention of the release of angiogenic growth factors

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

• the degree of electronic interaction between the donor PTZ and acceptor Pe moieties, as indicated by the decreased overlap between HOMO and LUMO. UV–vis absorption spectra of the Pe–PTZ derivatives were recorded in benzene at room temperature (Figure 3a). All compounds exhibited characteristic

• than that of the LE band of the Pe moiety in other compounds. This suggests that the phenyl spacer effectively suppressed the CT interaction. It is noted that the substitution of the TPA group increases the relative amplitude of the CT emission band. On the other hand, it was found that the intensity

• dynamics of these molecules, transient absorption spectroscopy measurements spanning the femtosecond to microsecond timescales were conducted. When electron transfer occurs between the donor and acceptor, the spin–spin interaction becomes weaker, facilitating the formation of triplet excited states upon

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

• two NH sites remained uncoordinated due to steric hindrance. Non-covalent interaction (NCI) plot analysis revealed distinct intramolecular π–π dispersion interactions between the two aza[5]helicene moieties (green surface in Figure 4b) [29][30][31]. Optical properties The electronic absorption and

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

• frontier molecular orbital (FMO) theory. Nitrile oxides are considered to be "type II" dipoles capable of reacting both through the interaction of HOMOdipole–LUMOdipolarophile and LUMOdipole–HOMOdipolarophile [35]. According to the results presented in [36], reactions with benzonitrile oxide can satisfy

• this case, the strong electron-withdrawing properties of the carboxyethyl group in CEFNO can significantly inhibit the reaction with 2f, lowering the energy of the HOMOdipole involved in the interaction. Instead, the reaction can proceed towards dipole dimerization [37], which is generally much easier

General method for the synthesis of enaminones via photocatalysis

• Paula Pérez-Ramos,
• Raquel G. Soengas and
• Humberto Rodríguez-Solla

Beilstein J. Org. Chem. 2025, 21, 1535–1543, doi:10.3762/bjoc.21.116

• adduct 10 was identified using GC–MS (Figure S1, Supporting Information File 1). When the reaction was performed under air-equilibrated conditions, the intended product 9a was obtained in a 31% yield, indicating that air influenced the interaction between the Ni-catalyst and the α,β-unsaturated carbonyl

• , pseudo-octahedral Ni(II) complex [44] involving the carbonyl groups of PS1 and 7a, which is further activated on aggregation of the pyridinium salt and the chromone aromatic ring through π−π stacking. Then, PC1 was submitted to Stern–Volmer quenching experiments. Whereas no interaction occurred between

• the excited form of PC1 and 3-bromochromone (7a), a direct interaction occurred between PC1* and morpholine (8a, Figure S3, Supporting Information File 1). Based on these results, the most plausible scenario might be that the reaction starts with the excitation of PC1 at 427 nm to generate the highly

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

• drastically reduced in MeCN (Figure S7 in Supporting Information File 1). This can be attributed to the less favorable protonation in MeCN as shown in Table 1. The interaction between compounds 1–3 and MSA was studied computationally by geometry-optimizing their ion pairs, denoted as 1H+MSA−, 2H+MSA−, and 3H

• −MSA), which acts as a single thermodynamic unit. However, interactions with solvent molecules, underrepresented in implicit solvation models, may weaken this interaction in practice [31][32]. Since a solvent’s dielectric constant increases when temperature decreases, the higher ∆H° values at lower

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

• voltage, which is ≈1.1 V. This suggests that while switching, the molecules may not be in their neutral state. Since the graphite–molecule interaction is weak and van der Waals-type, we use the gas-phase calculations and no major change in the electronic structure is expected for molecules upon adsorption

• charging, the potential energy landscape of isomerization changes, which supports the isomerization. As graphite–molecule interaction is weak and makes a capacitive interface between them, the molecules are likely stabilized in their ionic forms when a bias is applied at the tunneling junction. Charging of

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

• Andrei Paraschiv,
• Valentina Maruzzo,
• Filippo Pettazzi,
• Stefano Magliocco,
• Paolo Inaudi,
• Daria Brambilla,
• Gloria Berlier,
• Giancarlo Cravotto and
• Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

• changes in the position and shape of the νNH2 and δNH2 bands are observed, which are an indirect indication of the interaction of the amino group with the metal (curve b) [51]. On the other hand, major changes are observed in the spectrum of 5 wt % Si –MonoAm-Cu(II) (curve d). These are particularly

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

• . It should be noted, however, that the relative stabilization of KE and KK depends, in addition, on the strength of the intramolecular hydrogen bonding. The interaction C=O···H–N is much stronger, which leads to better stabilization of KE. Some border cases of substitution in the phenyl ring of 1 are

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

• (89%). Interestingly, the fusion of two azulene units at peri-position induces the significant orbital interaction, resulting in a very narrow HOMO–LUMO gap in 172. Consequently, 172 exhibits NIR absorption properties (λmax = 1180 nm, tail to 1720 nm) and reversible redox behaviours (electrochemical

A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones

• Ashutosh Nath,
• John Mark Awad and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92

• the dienophile presents a negative charge (−0.280 to −0.325, 6a), (−0.280 to −0.327, 6h) and (−0.280 to −0.327, 6r), respectively. This structure induces electrostatic repulsion instead of the requisite attraction for a successful interaction between the electron-rich diene and the electron-deficient

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• , thus confirming a strong interaction affinity lying within the 104 molar range. Gold extraction with β-CD and derivatives The possibility of using β-CD instead of α-CD in gold recovery and extraction is highly sought after by both researchers and industry because of the readiness of availability of β

• structures of the complexes of α-CD with KAuCN2 salts, with tubular representation for α-CD and space-filling for KAu(CN)2. The images at the center depict the interaction between one Au(CN)2− anion and one or two α-CD(s), according to the stoichiometry. The images at the sides depict the packing for the 1:1

Salen–scandium(III) complex-catalyzed asymmetric (3 + 2) annulation of aziridines and aldehydes

• Linqiang Wang and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1087–1094, doi:10.3762/bjoc.21.86

• of the catalyst for the next catalytic cycle. The electron-deficient aromatic aldehydes exhibit excellent stereoselectivity due to the π-stacking interaction between their aryl group and the electron-rich malonate group. Similar π-stacking interaction-controlled stereoselectivities were observed in

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• yield. The reaction proceeds via a CeO2-coordinated carboxylate mode (Scheme 31A) [67]. In addition, the catalyst also offered high reusability for up to 4 runs thus further promoting the eco-friendliness. Carbonyl activation via Lewis acid–O=C interaction has also been achieved using other transition

• hand, carboxyl activation via Lewis acid–O=C interaction has also been developed. Ramachandran and Hamann (2021) directly prepared the amide 12 from cinnamic acid (7) catalyzed by BH3. The reaction proceeds via formation of the triacyloxyborane–amine complex intermediate 132 (Scheme 40A) [76]. The same

• vinylphenylboronic acid to synthesize the solid-supported phenylboronic acid catalyst (cat 1) which was used to convert cinnamic acid (7) to its corresponding amide 12 in moderate yield. The reaction involves dicarboxylate complex 135 formed through Lewis acid B–O=C interaction (Scheme 41A) [23]. The catalyst could

Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts

• Valentina Benazzi,
• Arianna Bini,
• Ilaria Bertuol,
• Mariangela Novello,
• Federica Baldi,
• Matteo Hoch,
• Alvise Perosa and
• Stefano Protti

Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84

•  1 for CD-a-N-BB). Light-mediated reduction of triarylsulfonium salts. At this point, a Stern–Volmer analysis in the presence of tri-p-tolylsulfonium triflate (1b) as the model substrate was employed to quantify the quenching rate coefficient (Kq), in order to determine the interaction between the

• four different CDs from citric acid and from blackberries with triarylsulfonium salts. A diffusional rate value was found for all examined nanomaterials (Table 3), pointing to an efficient interaction between the photoexcited CDs and 1b. Cyclic voltammetry experiments have been carried out on both CDs

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

• Katy Medrano-Uribe,
• Jorge Humbrías-Martín and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

• CT stabilization of the first excited state of the molecule [34]. This observation is further supported by the orthogonal D–A conformation calculated using DFT, which indicates a decoupled interaction between the HOMO and the LUMO (Figure 2). Moreover, compound 5e is the only member of the family in

• facilitated by reduced photocatalyst (PC) and the interaction of 15 with the radical cation of DIPEA. The best result, again, was attributed to molecule 5a with 60% isolated yield (Table 5, entry 1). In contrast, molecule 5b showed the worst performance with 41% NMR yield (Table 5, entry 2). For compounds 5c

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• environment around the copper center disfavors a direct interaction with nucleophilic alkyl radicals. Instead, the reaction proceeds via an outer-sphere mechanism, where the alkyl radical reacts with the copper-activated C=N unsaturated bond, enabling stereocontrolled C(sp3)–C(sp3) coupling. In contrast, with

• the anionic cyano-substituted bisoxazoline ligand L7, the glycine ester and copper catalyst form a distinct intermediate complex Int-28. The ligand’s reduced steric bulk and altered electronic properties facilitate direct interaction with alkyl radicals, forming a high-valent Cu(III) intermediate Int

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

• to a solution of B4aH, the aromatic proton Ha exhibited continuous upfield shifts, while Hb initially shifted upfield and then downfield upon the addition of 1.5 equiv of C62− (Figure 2b and Figure S8 in Supporting Information File 1). These chemical shift changes indicate the interaction between the

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

• dual-host systems for selective ion separation. Keywords: anion binding; cesium extraction; dual-host strategy; ion-pair interaction; solid–liquid extraction; Introduction Ion-pair interaction, defined as the electrostatic attraction between a positively charged cation and a negatively charged anion

• interactions between K+ and C=O moieties [31], similar to these seen in the single crystal structures of KF and K2CO3 complexes. These provide a promising opportunity that can be used to identify the cooperative interaction underpinning complexed ions in dual-host strategy-based extraction. To do this, the

• ion-dipole interaction of the Li+ cation and carbonyl groups also contribute to the extraction. The negative electrostatic potential (δ−) of O=C is attributed to a high dipole moment of the urea unit (mono(urea): 3.95 D, bis(urea): 7.55 D) [34][35][36], which has been demonstrated to be capable of

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• docking scores (DS) revealed a range of binding affinities, with values ranging from −8.55 kcal/mol (iNOS–DEX) to −9.51 kcal/mol (iNOS–5e). Notably, iNOS–5e exhibited the most favorable binding energy, suggesting it has the strongest interaction with the iNOS enzyme. Hydrogen bonding analysis demonstrated

• enhance its interaction with iNOS via the optimization of the hydrogen bond with Cys200. These results highlight the potential of compound 5e as a lead compound for further development in targeting iNOS-related pathologies. Experimental results have confirmed that compound 5e is a promising candidate for

Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion

• Leon M. Friedrich and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57

• , not only the ligand but also the carbohydrate binding region of the protein is flexible, allowing for modeling of the ligand–FimH interaction as a dynamic event [52][53]. The five best binding poses of each receptor–ligand complex obtained in IFD were then used in a binding pose metadynamics

• with FimH (Supporting Information File 1, Figures S19–S21). In addition to the π–π interaction of the CRD-bound mannose-projecting antenna of the EE isomer with Tyr48, the complex is stabilized by hydrogen bonds of the scaffold mannoside to Tyr48 and in case of the glucose moiety to Thr51, Ile52, and

• Arg92, Asn138, and Asn135 in the ZE isomer. Comparison of the EE and the ZZ isomers of the homobivalent glycocluster 6αMan3αMan 2 also shows very different orientations of the second, non CRD-bound antenna. In case of the EE isomer, the π–π interaction of the CRD-complexed glycoazobenzene antenna with

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

• rotamers have different energies. When the C–F bonds are aligned gauche, the vacant σ* orbital of each C–F bond is able to mix with the filled σ orbital of an adjacent C–H bond, and this hyperconjugative interaction stabilises the gauche conformer (III, Figure 2). The anti conformer does not benefit from

• happens if fluorine is introduced onto one of the carbons that is directly attached to oxygen (Figure 6). This makes possible a hyperconjugative interaction between a lone pair on oxygen and the σ* orbital of the C–F bond (I, Figure 6) [76]. This interaction biases the rotational profile about the O–C(F

• ]. Glycosylation reactions (e.g., 63 → 65 and 64 → 66, Figure 9) proceed via an oxocarbenium intermediate. If fluorine is located at C-2, an electrostatic attraction might be expected between the partially negative fluorine and the positively charged C=O+ moiety, and this interaction would favour one of the half

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

• , interaction and function. Furthermore, the synthesis of both isomers of trifluoroleucine was described. (2S,4R)-Trifluoroleucine could be isolated on a milligram-scale in good yields and excellent enantiomeric purities, representing a viable synthetic route for these building blocks adding another strategy to

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

• -fold. These observations supported the hypothesis that the crown ether effectively disrupts the interaction between the alkali metal cation and fluorine atom, thereby decreasing the rate of β-F elimination. This asymmetric copper-catalyzed protocol represents one of the rare examples that allows to

• energy compared to (S,S)-TS9. Both transition states demonstrated a lithium center's coordination involving bromide, benzoate, and ligand oxygen atoms. The (S,R)-TS8 transition state exhibited a significantly shorter Li–Br interaction distance (2.81 Å compared to 3.74 Å in (S,S)-TS9), offering