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

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

• hybridized with various inorganic materials, such as metal-organic frameworks (MOFs), mesoporous silica nanoparticles (MSNs), metal nanoparticles, and carbon materials [87]. By designing through electrostatic and non-covalent interactions, PAs can be used as "molecular switches" to construct mechanized MOFs

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

• (the torsion angle: C8–C7–C6···Br = −80.3°). That is, the bromine atom interacts with three carbon atoms (C5–7); the three bond distances (Br···C5–7) and three bond angles (C–Br···C5–7) were 3.44, 3.30, 3.50 Å and 166.6, 155.9, 134.0°, respectively. Although a racemate, homochiral layered polymer

• , the chlorine atom interacts with two carbon atoms (C5 and C6) of the benzene ring, the two bond distances (Cl···C5,6) and two bond angles (C–Cl···C5,6) were 3.42, 3.27 Å and 164.5, 154.4°, respectively. The formation of homochiral layered polymers through intermolecular halogen–π interactions was also

Preparation of a furfural-derived enantioenriched vinyloxazoline building block and exploring its reactivity

• Madara Darzina,
• Anna Lielpetere and
• Aigars Jirgensons

Beilstein J. Org. Chem. 2025, 21, 1737–1741, doi:10.3762/bjoc.21.136

• attack to the double bond in intermediate A is kinetically preferred from the face forming the R-configured carbon of the C–N bond as a result of a minimized steric interaction of the oxygen in zwitterion with iPr substituent of oxazoline. Conclusion Unsaturated ester obtained by Torii-type ester

Convenient alternative synthesis of the Malassezia-derived virulence factor malassezione and related compounds

• Karu Ramesh and
• Stephen L. Bearne

Beilstein J. Org. Chem. 2025, 21, 1730–1736, doi:10.3762/bjoc.21.135

• proton (1H) spectra are reported relative to the residual solvent signal for CDCl3 (δ 7.26) or methanol-d4 (δ 3.31) [30]. Chemical shifts (δ in ppm) for carbon (13C) spectra are reported relative to the residual solvent signal for CDCl3 (δ 77.16) or methanol-d4 (δ 49.00) [30]. Abbreviations used for

• fully consistent with those published previously [20]. The observation of 19 carbon atoms in 1 (HRESIMS) and 10 carbon signals in the 13C NMR spectrum is in accord with the molecule being symmetric. The structure of di-indole 1 was further supported by 2D NMR. The 1H-1H COSY spectrum showed couplings

• the connectivities of these groups were supported from the 1H-13C HMBC spectrum. Couplings between the H8 and C9 (or H8′ and C9) atoms are consistent with the C8 and C8′ atoms linked to the carbonyl carbon (C9). In addition, couplings between the H8 and the C2, C3, C3a, and C8 carbon atoms, as well as

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

• higher kinetic feasibility than aliphatic C-nitration in saturated carbon frameworks [3]. Following determination of substrate–nitrating agent combinations, reactor system specification emerges as the critical engineering decision. Nitration reactor selection – encompassing batch, semi-batch, continuous

• % are generally considered non-explosive; it is noteworthy that organic peroxides constitute a notable exception to this rule and require stringent safety measures. Indicator 2: number of carbon atoms per plosophoric group [69]. Materials with nitro functional groups may be classified as plosophoric

• process due to the inherent safety features (particularly in microreactor systems). In addition to evaluating it based on the three parameters mentioned above (the number of carbon atoms per plosophoric group, oxygen balance (OB) of the material, and nitrogen content), the raw materials, products, by

Influence of the cation in hypophosphite-mediated catalyst-free reductive amination

• Natalia Lebedeva,
• Fedor Kliuev,
• Olesya Zvereva,
• Klim Biriukov,
• Evgeniya Podyacheva,
• Maria Godovikova,
• Oleg I. Afanasyev and
• Denis Chusov

Beilstein J. Org. Chem. 2025, 21, 1661–1670, doi:10.3762/bjoc.21.130

• did not decrease the target product yield. Such functional groups as multiple carbon–carbon bonds (5, 12), COOR (3), NO2 (16), CN (19), heteroaromatic moieties (8, 9) remained intact under our reaction conditions. Compounds 1, 7, 10, and 13 were synthesized in the same yields as in the previous work

Catalytic asymmetric reactions of isocyanides for constructing non-central chirality

• Jia-Yu Liao

Beilstein J. Org. Chem. 2025, 21, 1648–1660, doi:10.3762/bjoc.21.129

• Jia-Yu Liao College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China 10.3762/bjoc.21.129 Abstract Beyond the conventional carbon-centered chirality, catalytic asymmetric transformations of isocyanides have recently emerged as a powerful strategy for the efficient synthesis

• , pioneered by Bringmann and co-workers [45], has proven to be a powerful approach for synthesizing axially chiral biaryls, particularly in the challenging case of sterically hindered tetra-ortho-substituted scaffolds [46][47]. In this context, α-acidic isocyanides have been successfully employed as carbon

• lactones with carbon nucleophiles. The success lies in the tandem enantioselective ring-opening of lactones with α-acidic isocyanides, followed by a rapid cyclization driven by aromatization, overcoming the long-standing stereochemical leakage problem caused by the undesired lactol formation [45

Photocatalysis and photochemistry in organic synthesis

• Timothy Noël and
• Bartholomäus Pieber

Beilstein J. Org. Chem. 2025, 21, 1645–1647, doi:10.3762/bjoc.21.128

• , the combination of nickel catalysis and photoredox catalysis has become one of the most studied strategies to forge carbon–carbon bonds. The groups of Soengas and Rodríguez-Solla used this strategy to develop a general method for the synthesis of enaminones [32]. Light-induced transition metal

Formal synthesis of a selective estrogen receptor modulator with tetrahydrofluorenone structure using [3 + 2 + 1] cycloaddition of yne-vinylcyclopropanes and CO

• Jing Zhang,
• Guanyu Zhang,
• Hongxi Bai and
• Zhi-Xiang Yu

Beilstein J. Org. Chem. 2025, 21, 1639–1644, doi:10.3762/bjoc.21.127

• introduce an ester group at the α position of the carbonyl group in 9 to get compound 10, which could have a more nucleophilic carbon better for the Heck reaction. 10 was obtained in 70% yield with a diastereomeric ratio of 4.5:1. Then, we screened various palladium catalysts and solvents to accomplish 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

• fluorophore are graphically defined. Fully optimized structures (B3LYP-D3BJ/6-311++G(d,p)&DefTZVPP(Ba) level of theory) of compounds 18 and 18·Ba2+ at the ground (S0, carbon atoms in gray) and first excited (S1, carbons in orange) sates. Bond distances are given in Å. The dihedral angles ω = a–b–c–d, in

3-Aryl-2H-azirines as annulation reagents in the Ni(II)-catalyzed synthesis of 1H-benzo[4,5]thieno[3,2-b]pyrroles

• Julia I. Pavlenko,
• Pavel A. Sakharov,
• Anastasiya V. Agafonova,
• Derenik A. Isadzhanyan,
• Alexander F. Khlebnikov and
• Mikhail S. Novikov

Beilstein J. Org. Chem. 2025, 21, 1595–1602, doi:10.3762/bjoc.21.123

• unique ability of these compounds to undergo selective opening of the three-membered ring at either of the two nitrogen–carbon bonds under certain conditions and to be incorporated into the target molecule as a N‒C‒C synthon is successfully used to obtain a variety of heterocyclic and acyclic nitrogen

pH-Controlled isomerization kinetics of ortho-disubstituted benzamidines: E/Z isomerism and axial chirality

• Ryota Kimura,
• Satoshi Ichikawa and
• Akira Katsuyama

Beilstein J. Org. Chem. 2025, 21, 1568–1576, doi:10.3762/bjoc.21.120

• calculated the distance between the imino carbon atom and the nitrogen atom of the NMe₂ moiety (d) for local minimum and transition-state structures (Figure 2). In the local minimum and transition state of the C–N rotation and C–N/C–C concerted rotation, protonation leads to a shortening of the C–N bond by

• made with little effect on the molecular structure and are widely used in areas such as carbon materials. If the three-dimensional structure of molecules can be manipulated by various external stimuli through such modifications, we can expect to develop useful molecular switches that can be applied to

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

• ][2][3][4][5]. In addition to these promising functionalities, their cyclic polyaromatic frameworks can be further transformed into fused structures. To this end, belt-like polyaromatic architectures can be developed, inspiring ongoing efforts toward the construction of carbon nanotube analogs (Figure

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

• another cycle via the single quaternary carbon atom C5 demonstrated significant biological activity, greater than analogs with non-spiro-bonded cyclic fragments [3][4]. Hydantoin derivatives also exhibit a wide range of biological activities. Compounds containing the hydantoin pharmacophore group, are

• more electronegative oxygen or nitrogen atoms, both in the HOMO of dipole and dipolarophile [36][39]. In contrast, the carbon atoms have a significantly higher orbital coefficient than the heteroatoms, both in the LUMOdipolarophile and the LUMOdipole. Thus, nitrile oxide tends to react with an imine to

• form two new carbon–heteroatom bonds in a 1,2,4-oxadiazoline ring through both variants of orbital overlap. It should be noted that, in this case, NMR spectroscopy is not applicable to assign the product structure due to the presence of only quaternary carbon atoms in the tetrasubstituted 1,2,4

Azide–alkyne cycloaddition (click) reaction in biomass-derived solvent Cyrene^TM under one-pot conditions

• Zoltán Medgyesi and
• László T. Mika

Beilstein J. Org. Chem. 2025, 21, 1544–1551, doi:10.3762/bjoc.21.117

• and atom-economical strategies for efficiently assembling new carbon–carbon [1][2][3] and carbon–heteroatom [4][5][6] bonds. Thus, it has become the most attractive and facile methodology for creating various complex organic molecular structures from the laboratory to the industrial scale. Among these

• successfully introduced into homogeneous [26][27][28][29] and heterogeneous [30][31] carbon–carbon and carbon–heteroatom bond-forming protocols. Although its reactive carbonyl group could limit its application when a strong base (aldol condensation [29]) or amines (potential Schiff-base formation) are present

• -triazoles in CyreneTM (Figure 4). It was shown that the protocol resulted in the formation of products 3a and 5b–f with yields of 57–91% depending on the structure of the bromide derivatives. The isolated yields were in the same range as reported by Citarella et al. [39]. The presence of a terminal carbon

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

• ; enaminones; nickel; photocatalysis; Introduction Enaminones are relevant intermediates in organic chemistry and the pharmaceutical industry [1][2][3][4][5][6]. These enamines have a carbonyl group conjugated to a carbon–carbon double bond, owing its great versatility in organic synthesis to its ability to

• electrophilicity of the β-carbon due to the electron-donating nature of the methyl group. Subsequently, we turned our attention to investigate a range of amine derivatives 8 under the standard conditions. When morpholine was replaced by piperidine, the expected enaminone 9g was provided, albeit in lower yield

• mechanism for this reaction is proposed in Scheme 5. A ternary complex is initially formed upon complexation of 3-bromochromone (7a) with NiBr2-dmbpy. By virtue of being coordinated to a Ni-center, the β-carbon is activated toward nucleophilic attack of the amine, furnishing 2-amino-3-bromochromenone I

Calcium waste as a catalyst in the transesterification for demanding esters: scalability perspective

• Anton N. Potorochenko and
• Konstantin S. Rodygin

Beilstein J. Org. Chem. 2025, 21, 1520–1527, doi:10.3762/bjoc.21.114

• phase (with reflections at 2θ = 32.4, 37.5, 54.0, 64.3, 67.5) to 73.5 wt % was detected due to the decomposition of the Ca(OH)2 phase; the amount of the Ca(OH)2 phase after calcination was 2.4 wt %. The amount of the CaCO3 phase increased to 17.6 wt %, probably due to the sorption of carbon dioxide or

Ambident reactivity of enolizable 5-mercapto-1H-tetrazoles in trapping reactions with in situ-generated thiocarbonyl S-methanides derived from sterically crowded cycloaliphatic thioketones

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Marcin Palusiak,
• Heinz Heimgartner,
• Marta Denel-Bobrowska and
• Agnieszka B. Olejniczak

Beilstein J. Org. Chem. 2025, 21, 1508–1519, doi:10.3762/bjoc.21.113

• of non-concerted, step wise cycloadditions leading to mixtures of five- and seven-membered heterocyclic products (cycloadducts), and respective zwitterionic intermediates were postulated to explain the unexpected reaction pathway [11]. Due to the practically equal electronegativity of carbon and

• analysis (Figure 1a and Figure 1b, respectively). Single crystals of 9i and 10i were obtained by slow evaporation from a hexane/CH2Cl2 solution and subsequently used for crystallographic X-ray measurements. In the case of 9i, the molecule is strongly disordered in the outer carbon ring regions. However

Heterologous biosynthesis of cotylenol and concise synthesis of fusicoccane diterpenoids

• Ye Yuan,
• Zhenhua Guan,
• Xue-Jie Zhang,
• Nanyu Yao,
• Wenling Yuan,
• Yonghui Zhang,
• Ying Ye and
• Zheng Xiang

Beilstein J. Org. Chem. 2025, 21, 1489–1495, doi:10.3762/bjoc.21.111

• enzymatic terpene cyclization and chemical synthesis [30][31][32][33]. Briefly, the carbon scaffolds are forged by terpene cyclases, followed by concise chemical transformations to yield the desired natural products. Here, we describe heterologous biosynthesis of cotylenol by engineering the biosynthetic

• biosynthetic pathway for brassicicenes, which share the same carbon skeleton and similar oxidation and unsaturation states as cotylenol and cotylenin A [36]. In a previous study, Oikawa and co-workers reported the identification of brassicicene BGC in Pseudocercospora fijiensis [37]. By heterologous expression

Copper catalysis: a constantly evolving field

• Elena Fernández and
• Jaesook Yun

Beilstein J. Org. Chem. 2025, 21, 1477–1479, doi:10.3762/bjoc.21.109

• allenes with diisobutylaluminum hydride, which is followed by the allylation with p-toluenesulfonyl cyanide in a regio- and stereoselective manner. They propose a new way to access accessing acyclic β,γ-unsaturated nitriles with α-all-carbon quaternary centers. In the process, they managed to achieve a

Wittig reaction of cyclobisbiphenylenecarbonyl

• Taito Moribe,
• Junichiro Hirano,
• Hideaki Takano,
• Hiroshi Shinokubo and
• Norihito Fukui

Beilstein J. Org. Chem. 2025, 21, 1454–1461, doi:10.3762/bjoc.21.107

• containing one or two exocyclic olefin units. Owing to the transformation of carbonyl groups, the resulting products exhibit several unique physical and chemical properties: (1) the enhancement of configurational stability, (2) the appearance of fluorescence, and (3) the reductive carbon–carbon-bond

• . A tentative mechanism that may be plausible is shown in Supporting Information File 1, Figure S21, which consists of (1) the nucleophilic attack of methylenetriphenylphosphorane to the exo-methylene group of 3, (2) the intramolecular carbon–carbon-bond formation at the carbonyl group, and (3) the

• Cc space groups, respectively. The bond lengths at the exocyclic olefin units of 3 and 5 are 1.336(2) and 1.333(3)–1.337(3) Å, respectively, which are typical for carbon–carbon double bonds. The (CH2CH2O)-substituted DBC derivative 4 adopts a double-helicene-like structure similarly to other

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• structures, enhance solubility, and expand functional diversity [6]. Substituting carbon atoms with electron-deficient nitrogen atoms introduces new opportunities to fine-tune redox potentials, charge-transport behavior, and intermolecular interactions [7]. These modifications have proven especially valuable

• demonstrated absorption at 368 and 516 nm, strong emission at 553 nm, a high PLQY of 0.96, |gabs| of 1.1 × 10−2, |glum| of 9.1 × 10−4, and BCPL of 30.1 M−1 cm−1 – surpassing the performance of its all-carbon and thiadiazole counterparts [29]. In a related study, Hu’s team synthesized double aza[5]helicenes 17a

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

• is a result of fast exchange between 1E and 1KE and the minor conformer can be attributed to 1KK. The measured carbon spectrum of 1 in CD3CN at 243 K (Figure S8 in Supporting Information File 1) supports this assignment as well. The HSQC spectrum (Figure S9 in Supporting Information File 1) helps in

• the assignment of the carbon spectrum. The proton signal at 16.59 ppm seems to be a sum of two signals and a deconvolution with Lotenzian bandshape function was performed (Figure S5 in Supporting Information File 1). The obtained two signals have an integral intensity of 78 to 22, which is in

• GIAO approximation [120]. The calculated absolute shieldings were transformed to chemical shifts using the reference compound tetramethylsilane (Si(CH3)4), for hydrogen and carbon atoms: δ = δcalc(ref) − δcalc. Both δcalc(ref) and δcalc were evaluated at the same computational level (M06-2X/TZVP

Reactions of acryl thioamides with iminoiodinanes as a one-step synthesis of N-sulfonyl-2,3-dihydro-1,2-thiazoles

• Vladimir G. Ilkin,
• Pavel S. Silaichev,
• Valeriy O. Filimonov,
• Tetyana V. Beryozkina,
• Margarita D. Likhacheva,
• Pavel A. Slepukhin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2025, 21, 1397–1403, doi:10.3762/bjoc.21.104

• 2,3-dihydro-1,2-thiazole ring are in the range of 75.3–72.4 ppm and signals of the carbon atom of the cyano group in the range of 117.7–116.6 ppm. The structure of 2,3-dihydro-1,2-thiazole 3aa was additionally confirmed by single crystal X-ray diffraction (Figure 2). According to the X-ray diffraction