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Search for "oxygen" in Full Text gives 1293 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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

Graphical Abstract
  • within the average molecular plane. In addition, the corresponding ΔGiso values increase with the n-values (Figure 4A). Ligand 21-crown-7 15d suggests that this size of the cyclic ligand is less than optimal, since the calculated structure shown a concave-convex topology, in which one oxygen atom
  • , highlighted by an asterisk, lies out from the direct coordination perimeter, thus suggesting that this ligand is too big. The relatively lower increase of the ΔGiso(d) with respect to its ΔGiso(c) congener also indicate that the stabilization induced by the additional oxygen atom is lower in magnitude. An
  • central position within the concave face. Also in this case, one oxygen atom of the oversized macrocycle does not interact directly with Ba2+, thus resulting in a non-optimal coordination pattern. Therefore, the shape of the ligand and the low positive charge available for the cation result in the largest
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Published 13 Aug 2025

Transition-state aromaticity and its relationship with reactivity in pericyclic reactions

  • Israel Fernández

Beilstein J. Org. Chem. 2025, 21, 1613–1626, doi:10.3762/bjoc.21.125

Graphical Abstract
  • )> molecular orbital overlap (S = 0.13 vs S = 0.07 for the uncatalyzed and catalyzed reactions, respectively). In other words, there occurs a significant polarization of the conjugated π-system away from the C–C double bond when the LA binds the carbonylic oxygen of methyl acrylate, which results in a less
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Perspective
Published 12 Aug 2025

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

Graphical Abstract
  • displayed lifetimes in the order of several microseconds. In contrast, under an oxygen atmosphere, the transient absorption decayed significantly faster, confirming the triplet nature of these states (Figure 5b and Figures S25–S27 in Supporting Information File 1). Under a nitrogen atmosphere, the decay
  • . Microsecond transient absorption (a) spectra and (b) dynamics of Pe–PTZ(TPA)2 in benzene excited at 355 nm (5 μJ/pulse) and probed at 430 nm under nitrogen and oxygen conditions. Femtosecond-to-nanosecond transient absorption spectra and evolution-associated spectra (EAS) of Pe–PTZ(TPA)2 in benzene excited at
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Published 05 Aug 2025

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

Graphical Abstract
  • formal substitution of the carbonyl oxygen atom of DiBA to an NH group, could act as a pH-responsive molecular switch (Figure 1c). Namely, the double-bond nature of an amidine moiety can be altered by the protonation of the amidine nitrogen atom. This suggests the possibility of controlling the rate of C
  • usefulness of the single-atom substitution strategy on DiBA. By replacing the oxygen atom of DiBA with a nitrogen atom (and thus NH), which has been shown to be photo-responsive when replaced with sulfur or selenium, the pH-responsive property was acquired. Such minimal changes in physical properties can be
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Letter
Published 04 Aug 2025

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

Graphical Abstract
  • 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
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Published 31 Jul 2025

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

Graphical Abstract
  • complexes between 1–3 and MSA (X-MSA and X-(MSA)2, X = 1, 2 or 3). The geometry-optimized structure of 3H+MSA−MSA is shown in Figure 3. In this structure, the second MSA molecule does not bind directly to the azo group but forms a hydrogen bond with the mesylate anion, and one of its oxygen atoms interacts
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Published 28 Jul 2025

Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides

  • Nadezhda M. Metalnikova,
  • Nikita S. Antonkin,
  • Tuan K. Nguyen,
  • Natalia S. Soldatova,
  • Alexander V. Nyuchev,
  • Mikhail A. Kinzhalov and
  • Pavel S. Postnikov

Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110

Graphical Abstract
  • oxygen significantly inhibited the reaction. Based on these findings and some additional experiments (see Supporting Information File 1, Table S1), the optimal conditions for further studies were established as the use of equimolar amounts of diaryliodonium salt and isonitrile, Na2CO3 as the base, and
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Published 21 Jul 2025

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

Graphical Abstract
  • conditions already reported in the literature for aerobic protocols. As shown in Table 1, entries 1–3, we compared xylene, toluene, and acetonitrile as solvents. According to Bhanage and Wagh [13], Cu(II) catalyses the C–H amination in xylene at 140 °C for 14 hours under oxygen. We tested the reaction in
  • demonstrated good product conversion and selectivity without the need to perform the reaction under oxygen, while Cu(OAc)2 was slightly less efficient. When the catalyst loading was reduced to 15 mol %, the reaction yield decreased to approximately 75% for both copper salts. However, reducing the reaction time
  • 13%, highlighting the importance of oxygen/air in the oxidative aromatisation of the benzoxazole ring. Reducing the reaction time to 1 hour or lowering the catalyst loading to 15 mol % resulted in decreased yields of 75% and 71%, respectively. The reaction was also carried out in Anton Paar equipment
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Published 15 Jul 2025

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

Graphical Abstract
  • nucleophilic substitution of the thus generated alkoxide to form an oxygen-containing five-membered ring. At least, density functional theory (DFT) calculations support that the nucleophilic attack of methylenetriphenylphosphorane to the exo-methylene unit is slightly favorable over reaction with the carbonyl
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Letter
Published 14 Jul 2025

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

Graphical Abstract
  • emitters. Boron–nitrogen co-doping strategies, in particular, have facilitated the development of materials with ultra-narrowband emissions, near-unity photoluminescence quantum yields, and electroluminescence dissymmetry factors (|gEL|) exceeding 10−3. Likewise, heteroatom co-doping with oxygen, sulfur
  • helicenes. Particular attention is given to multi-heteroatom systems co-doped with elements such as boron, oxygen, sulfur, and selenium, highlighting their influence on CPL performance and structure–property relationships. We classify the nitrogen-doped helicenes into only N-containing helicenes, B,N
  • stimuli-responsive chiral electrochromic materials. In the same year, You’s group developed a transition-metal-catalyzed C–H/C–H-type regioselective C3-arylation of benzothiophenes using molecular oxygen as the oxidant [79]. This strategy afforded the TADF-active compound 64a, which exhibits efficient
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Review
Published 11 Jul 2025

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

Graphical Abstract
  • not allow a ground-state tautomeric process to occur. Bearing in mind the requirements for clean switching, where the tautomeric proton is transferred from the oxygen atom to the nitrogen atom of the quinolyl moiety (i.e. from E to K), a theoretical design was performed in order to see the most
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Published 10 Jul 2025

Oxetanes: formation, reactivity and total syntheses of natural products

  • Peter Gabko,
  • Martin Kalník and
  • Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

Graphical Abstract
  • chemistry; natural products; oxetane; reactivity; synthesis; Introduction Oxetanes are 4-membered heterocyclic compounds containing one oxygen atom whose discovery dates back to the 1870s when the first synthesis of the parent, unsubstituted oxetane was reported by Reboul [1]. Over the next 100 years, it
  • in cyclobutane [3] – this difference is most likely caused by fewer gauge interactions in oxetane where one of the methylene units is replaced by oxygen. The authors also reported bond angles and lengths which are shown in Figure 1. As expected, the endocyclic angles are far from the ideal
  • tetrahedral value which results in a large ring strain of 25.5 kcal/mol, comparable to oxirane (27.3 kcal/mol) and much greater than tetrahydrofuran (5.6 kcal/mol) [4]. Moreover, the strained C–O–C bond angle effectively exposes the oxygen lone pairs, making oxetane a strong hydrogen-bond acceptor and Lewis
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Published 27 Jun 2025

Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer

  • Hao-Sen Wang,
  • Lin Li,
  • Xin Chen,
  • Jian-Li Wu,
  • Kai Sun,
  • Xiao-Lan Chen,
  • Ling-Bo Qu and
  • Bing Yu

Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100

Graphical Abstract
  • to produce amidyl radicals and oxygen anions in the presence of photocatalysts activated by visible light. Two representative cases illustrating this approach were reported in 2023. Building upon the experiments conducted by Alexanian’s group, Yan’s group extended the applicability of carborane as a
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Published 27 Jun 2025

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

Graphical Abstract
  • radical A. This is followed by the conversion of a substrate containing C(sp3)–H bonds adjacent to an oxygen atom into an alkyl radical intermediate B. The alkyl radical intermediate then adds to the C=C bond of N-arylacrylamide, generating a second alkyl radical intermediate C, which undergoes
  • then reacts with sodium trifluoromethanesulfinate (36) to form a sulfonyl hypobromite intermediate 38 (Scheme 20). This intermediate undergoes reduction at the cathode, leading to the formation of oxygen-centered and sulfonyl-centered radicals, which subsequently form a trifluoromethyl radical. This
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Published 24 Jun 2025

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

  • Alexander S. Budnikov,
  • Igor B. Krylov,
  • Fedor K. Monin,
  • Valentina M. Merkulova,
  • Alexey I. Ilovaisky,
  • Liu Yan,
  • Bing Yu and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

Graphical Abstract
  • reaction times, and scope limitations. In the present work, the selective copper(II)-mediated phosphorylation of enol acetates with the formation of substituted β-ketophosphonates employing cheap copper sulfate as a catalyst and atmospheric oxygen as a terminal oxidant was carried out (Scheme 1c). Results
  • radical was detected by HRMS, which supported a radical mechanism. Next, the influence of the atmosphere and the role of copper catalyst was evaluated (Scheme 4, reaction 2). Neither under argon nor under an oxygen atmosphere, the yield of 3a did not exceed 22%. However, employing 200 mol % of copper(II
  • ) sulfate under an argon atmosphere afforded 3a in 33% yield. These results indicate, that copper(II) at high loading is capable of oxidizing H-phosphonate even in inert conditions [72]; however, a balanced concentration of oxygen in the reaction mixture is required for recycling of copper catalyst and
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Published 20 Jun 2025

Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups

  • Julius Seumer,
  • Nicolai Ree and
  • Jan H. Jensen

Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94

Graphical Abstract
  • resulted in more specific SMARTS patterns matching the DG. For example, Figure 3a shows the result from Tomberg et al. [9], which does not include the carbonyl oxygen in the SMARTS pattern match although the pattern marked in red in Figure 3b is part of the database. This example also highlights that in
  • metal (the two oxygen atoms from the acetate moiety, the carbon atom from the reaction site, and the heteroatom from the directing group) is analysed without regard for connectivity. All four atoms have to lie within a plane after the optimization for the optimization to be considered successful. This
  • is determined by calculating the angle between the normal vectors of the plane spanned by Pd, the reaction site and the heteroatom of the directing group and the plane spanned by Pd and the two oxygen atoms of the acetate moiety. This angle has to be below 5° for the atoms to be considered to be
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Published 16 Jun 2025

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

Graphical Abstract
  • intermediate 7, the carbonyl oxygen interacts with AlCl₃, enhancing the electrophilicity and promoting the rearrangement to form stable oxonium ions. The removal of water from 7 is facilitated by protonation, producing reactive carbocations which undergo dehydrative aromatization to produce products 8
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Published 13 Jun 2025

A versatile route towards 6-arylpipecolic acids

  • Erich Gebel,
  • Cornelia Göcke,
  • Carolin Gruner and
  • Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

Graphical Abstract
  • . This tendency of amine bases in cross-coupling reactions aligns with the literature [44][45][46], reporting that they are either superior to or significantly outperformed by oxygen-based bases, depending on the conditions and substrates. K2CO3 was found to be the most suitable base, having similar
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Published 04 Jun 2025

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

  • Krishna Pandey,
  • Lucas X. Orton,
  • Grayson Venus,
  • Waseem A. Hussain,
  • Toby Woods,
  • Lichang Wang and
  • Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

Graphical Abstract
  • pattern of assembly between HIM and metal cation in 2:1 ratio. While association with sodium leads to a polymer-like network, the lithium crystal structure was limited to dimeric assemblies of HIM. In the lithium-coordinating complex, the oxygen–lithium–oxygen bond angle is approximately 98.83
  • °, displaying a closer arrangement of two HIMs. In contrast, the sodium complex exhibits a more open orientation of two HIMs with an oxygen–sodium–oxygen bond angle close to 167.98°. Lastly, a comparative study of association constants and binding energies for phenylalanine-based HIM with LiBArF20 and NaBArF24
  • system [12]. In addition to these covalent bonding interactions, additional secondary bonding (e.g., red-dotted bonds between iodine and oxygen in phenylalanine-based hypervalent iodine macrocycle in benzene system in Figure 1A) can arise in these systems from neighboring atom lone pairs. Secondary
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Published 30 May 2025

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

Graphical Abstract
  • enantioselectivities and high diastereoselectivities. A reasonable reaction mechanism was proposed and rationalized the experimental results. Keywords: aldehyde; annulation; aziridine; oxazolidine; ring expansion; scandium triflate; Introduction Oxazolidine derivatives are an important class of nitrogen and oxygen
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Published 28 May 2025

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

Graphical Abstract
  • such diradicals and we group the molecules in accordance with their type of conjugation. Kekulé-conjugated diradicals Trityl radicals and trityl-derived diradicals have been reported to be instable especially under light irradiation and in the presence of oxygen. As for the monoradicals, also
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Published 21 May 2025

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

Graphical Abstract
  • response, respiratory, vasodilation, apoptosis, tumor growth, and cardiovascular system [1][2]. Nitric oxide (NO) is released as product of the NADPH and oxygen-dependent oxidation of ʟ-arginine to ʟ-citrulline under the catalysis of the enzyme nitric oxide synthase (NOS) [3]. There are three distinct
  • a dihedral angle of 49.86(10) 86.22(11)° with the phenyl rings C6–C11 and C18–C23, respectively. The angle between both phenyl rings is 70.76(11)°. The stereochemistry around the double bond is Z, allowing an intramolecular N–H···O hydrogen bond between one of the carbonyl oxygen atoms and the amino
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Published 24 Apr 2025

Synthesis and photoinduced switching properties of C7-heteroatom containing push–pull norbornadiene derivatives

  • Daniel Krappmann and
  • Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

Graphical Abstract
  • ) derivatives. Push–pull substitution on the 2 and 3 position as well as introduction of oxygen or nitrogen at position 7 of the NBD scaffold have led to the development of a new family of photoswitches. We studied the potential conversion of norbornadiene to quadricyclane (QC) isomers. As main investigation
  • the corresponding boronic acid in a degassed toluene/H2O mixture (4:1, v/v) which was heated to 80 °C for 18 h (for detailed information see Supporting Information File 1). Using the described procedure, the oxygen containing derivatives O-NBD2 and nitrogen substituted N-NBD2 were successfully
  • absorption maximum and onset was observed for the heterocyclic derivatives in relation to their isocyclic analogues. Basic principle of the NBD to QC conversion and vice versa. The bridge-atom at position 7 was varied to carbon, oxygen or nitrogen. The back-conversion induced via heat or a catalyst can
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Published 22 Apr 2025

Recent advances in the electrochemical synthesis of organophosphorus compounds

  • Babak Kaboudin,
  • Milad Behroozi,
  • Sepideh Sadighi and
  • Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

Graphical Abstract
  • synthesis of various organophosphorus compounds through the formation of phosphorus–carbon, phosphorus–nitrogen, phosphorus–oxygen, phosphorus–sulfur, and phosphorus–selenium bonds. The impact of different electrodes is also discussed in this matter. Graphite, platinum, RVC, and nickel electrodes have been
  • organophosphorus compounds, in which phosphorus is attached to carbon or heteroatom centers. In this article, we describe recent advances in electrochemical green methods for the synthesis of various organophosphorus compounds through the formation of phosphorus–carbon, phosphorus–nitrogen, phosphorus–oxygen
  • reaction. Some of their applications include hydrogen and oxygen production, metal electroplating, and organic compound synthesis using electrochemical methods. Depending on the reaction conditions, these cells can be divided or undivided. Divided vs undivided cells In divided cells, oxidation and
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Published 16 Apr 2025

New advances in asymmetric organocatalysis II

  • Radovan Šebesta

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

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  • commonly defined as a form of catalysis where a small organic molecule, an organocatalyst, accelerates a chemical reaction. Unlike previously regarded traditional catalysts involving metals or enzymes, organocatalysts are composed of nonmetal elements, such as carbon, hydrogen, nitrogen, oxygen, phosphorus
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Editorial
Published 15 Apr 2025
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