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Search for "O-" in Full Text gives 2168 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides
Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110
- achieved in case of o-halo-substituted diaryliodonium salts providing 64% and 67% for amides 2bg and 2bh, respectively. In contrast, iodonium salts with electron-rich aryls afforded the corresponding benzamides 2aa, 2ba, 2bb, 2bf, and 2bk in significantly lower 19–36% yields. Subsequently, various
- not significantly change for EWG- or EDG-substituted species except for extreme cases [44]. Additionally, such reactivity pattern cannot be explained only by steric factors since the yield dramatically dropped for o-methyl-substituted iodonium salt 1f compared to o-halo-substituted salts 1g and 1h
Copper catalysis: a constantly evolving field
Beilstein J. Org. Chem. 2025, 21, 1477–1479, doi:10.3762/bjoc.21.109
- . In their contribution, Son et al. focus on transformations via the formation of copper nitrenoids, particularly amidations via oxidative insertion to N–O bonds and reductive elimination, and a small number of other reactions. The final Review by Cho, Lee, and co-workers is useful for the scientific
Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper
Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108
- open derivative, and the subsequent ring oxidation upon closure (as shown in the mechanism in Scheme S1 (Supporting Information File 1), the reaction mixture may contain the desired 2-substituted benzoxazole 2a together with its open-form precursor 2a-o. The latter can be hydrolysed to give N
- -formylpiperidine and aminophenol (2a-o-hydrol) (see Figure 1a). To better understand the influence of the reaction conditions on product distribution, we plotted conversion versus selectivity in Figure 1b. Crudes were analysed by 1H NMR spectroscopy, as shown in Figure S1 (Supporting Information File 1), to
- determine the percentage composition of starting material and products 2a, 2a-o and 2a-o-hydrol. The reaction was perfectly reproducible and no other derivatives were observed. As shown in Figure 1b, when the reaction was conducted without a catalyst, only ring opening was observed, accounting for 47%. By
Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications
Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106
- helical architectures, have attracted considerable attention due to their intrinsic chirality and tunable optoelectronic properties. Among them, nitrogen-doped helicenes (azahelicenes) and their heteroatom-co-doped counterparts – such as B/N-, O/N-, S/N-, and Se/N-doped helicenes – have emerged as highly
- -containing helicenes, and X,N-containing helicenes (X = O, S or Se). In each section, structurally similar compounds are categorized into groups to facilitate comparison. Then, the others are discussed in chronological order based on their reported publication dates, with attribution to the respective
- of helical aza-BODIPY analogues 43a–h, featuring a distinctive B–O–B bridge installed within each molecule [58] (Table 15). These compounds display broad chiroptical responses extending from the ultraviolet to the entire visible spectrum – an uncommon characteristic among helicene-type systems. Among
Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds
Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105
- =O group of the keto tautomers [51][56]). The effects of acetone, methanol and DMSO, as seen, are based only on the increased (comparing to toluene) dielectric constant of the solvent, stabilizing in different extent the more polar KE and KK. The further increase of the polarity of the environment by
- equilibrium towards C=O-group-containing structures. In addition, the spectra in the remaining solvents show a single band around 500 nm independent on the nature of the solvent. Obviously, these data cannot be interpreted in the frame of the concept for a tautomeric equilibrium. The rotor in 2 contains a OH
- . 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
Reactions of acryl thioamides with iminoiodinanes as a one-step synthesis of N-sulfonyl-2,3-dihydro-1,2-thiazoles
Beilstein J. Org. Chem. 2025, 21, 1397–1403, doi:10.3762/bjoc.21.104
- Vladimir G. Ilkin Pavel S. Silaichev Valeriy O. Filimonov Tetyana V. Beryozkina Margarita D. Likhacheva Pavel A. Slepukhin Wim Dehaen Vasiliy A. Bakulev TOS Department, Ural Federal University, 19 Mira str., Yekaterinburg 620002, Russia Department of Organic Chemistry, Perm State University, 15
- thioamides 1h,i,k,n,o,s,t,v,w,y,z (general procedure). A mixture of the corresponding thioacetamide (1.0 equiv), aldehyde (1.1–4.0 equiv) and DBU (0.1 equiv or 1.0 equiv for 1h,o) in ethanol was stirred for 2–23 h at room temperature. For thioamide 1i, the reaction time was 96 h at 80 °C. The formed
N-Salicyl-amino acid derivatives with antiparasitic activity from Pseudomonas sp. UIAU-6B
Beilstein J. Org. Chem. 2025, 21, 1388–1396, doi:10.3762/bjoc.21.103
- Joy E. Rajakulendran Emmanuel Tope Oluwabusola Michela Cerone Terry K. Smith Olusoji O. Adebisi Adefolalu Adedotun Gagan Preet Sylvia Soldatou Hai Deng Rainer Ebel Marcel Jaspars Department of Chemistry, Faculty of Science, Eastern University, Vantharumoolai, Chenkalady, Sri Lanka Marine
High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters
Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102
- imidazole-based N-heterocyclic carbene (NHC)–CuCl complexes [40]. However, their synthesis is often tainted by the use of toxic reagents and solvents. In addition, when o-phenylenediamine reacts with ketones, the common catalytic methods yield benzodiazepine products [41]. In our case the reaction of o
- -phenylenediamine and acetone was selected as a model reaction. The optimization of the reaction conditions is summarized in Table 1. All reactions were carried out at room temperature without involving any catalyst or additional solvent. While o-phenylenediamine is solid, it dissolves well in the reactant acetone
- of catalyst- and solvent-free processes is desirable. Chalcones are a privileged scaffold in medicinal chemistry and are used for the synthesis of a multitude of products [43]. The cyclization between chalcones and hydrazines usually occur via a C=O/NH2 condensation and a subsequent NH addition to
Oxetanes: formation, reactivity and total syntheses of natural products
Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101
- 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
- categorised into 6 synthetic strategies as depicted in Scheme 1: a) C–O bond-forming cyclisations, b) C–C bond-forming cyclisations, c) [2 + 2] cycloadditions between carbonyls and alkenes, d) ring expansions, e) ring contractions and f) O–H insertions. In the following subchapters, these strategies will be
- discussed in more detail and illustrated by specific examples. 1.1 C–O bond-forming cyclisations 1.1.1 Intramolecular Williamson etherifications: Discovered by Alexander Williamson in 1850, this reaction is an SN2 substitution in which a leaving group, typically a halide or sulphonate ester, is displaced by
Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer
Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100
- (SET) process by the cleavage of the N–O bond; (c) direct homolytic cleavage of weak N–S or N–X bonds in HRP initiated in the presence of visible light; (d) the intersystem crossing (ISC) of S1 to T1 state directly from the amide anion. This review is organized by bond cleavage type, offering a deep
- the photocatalyst [Ir(dF(CF3)ppy)2(4,4'-d(CF3)bpy)]PF6 in combination with a base (NBu4OP(O)(OBu)2) (Scheme 1) [59]. The generation of amidyl radical 5 involved a stepwise PCET process catalyzed by the combined effect, in the presence of photocatalyst and the base. Subsequently, amidyl radical 5
- a central role in this photocatalytic system. This strategy demonstrated good chemical selectivity for the functionalization of pyridine and alkanes, resulting in 55% to 86% yields of products 38, 39, 40, and 41, respectively. Amidyl radical from N–O bond cleavage In 2022, Alexanian’s group
Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes
Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99
- CHCl3, AcOH and o-DCB [44]. The resulting mixture of brominated PAHs 30 and 31 was then subjected to single or double [3 + 2] annulation with various alkynes, leading to the extended structures 32 and 33. Notably, compound 33d can undergo Pd-catalysed dimerization, resulting in the formation of a chiral
Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents
Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98
- temperature, and solvents. The optimal conditions were identified as using 10 mol % Sc(OTf)3 and 2 equivalents of Ag2O at 120 °C under an argon atmosphere. The substrate scope was then evaluated using various o-alkynylarylacrylamides and alkyl nitriles under the optimized reaction conditions. Substrates with
Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates
Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96
- Alexander S. Budnikov Igor B. Krylov Fedor K. Monin Valentina M. Merkulova Alexey I. Ilovaisky Liu Yan Bing Yu Alexander O. Terent'ev N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation M. V. Lomonosov Moscow State
Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups
Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94
- carbon atom), and the lowest DG strength if the other two priorities are unambiguous. Figure 2 and Table 1 show examples of the results from running the program with “CCCN(C)C(=O)c1ccc(C(=O)c2ccccc2)cc1” as the input SMILES string. The sites marked with red indicate the predicted reaction sites. The
Synthetic approach to borrelidin fragments: focus on key intermediates
Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91
- , successfully processing up to 15 g of starting material. Compound 93 was reduced to its corresponding aldehyde using DIBAL-H, followed by Horner–Wadsworth–Emmons (HWE) olefination with (EtO)2P(O)CH2COSEt, resulting in the unsaturated thioester 95. Reapplying the 1,4-addition reaction conditions to 95 produced
- 70% overall yield across three steps, with a dr exceeding 98:2. The reaction continued with the reduction of thioester 98 to aldehyde 99, followed by HWE olefination with (EtO)2P(O)CH2COMe, yielding compound 100 in 92% yield (Scheme 16). The stereocontrol achieved by the catalysts was again
- acetal in the presence of Hoveyda–Grubbs’ second-generation catalyst, affording aldehyde 112 in 75% yield as the E-isomer after a careful acidic workup. Finally, HWE olefination of aldehyde 112 with (EtO)2P(O)CHBrCN completed the synthesis of fragment 62b of borrelidin. Minnaard and Madduri emphasized
Investigations of amination reactions on an antimalarial 1,2,4-triazolo[4,3-a]pyrazine scaffold
Beilstein J. Org. Chem. 2025, 21, 1126–1134, doi:10.3762/bjoc.21.90
- purified by the Davis group [8]. In vitro antiplasmodial image-based assay Plasmodium falciparum 3D7 were cultured in RPMI1640 (Life Technologies, Camarillo, CA, USA) supplemented with 2.5 mg/mL Albumax II, 5% AB human serum, 25 mM HEPES, and 0.37 mM hypoxanthine. Human red blood cells (RBC) (O+) were
Gold extraction at the molecular level using α- and β-cyclodextrins
Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89
- cations, the geometry is different from that observed in {α-CD·[K(OH2)6]+[AuBr4]−}n, because coordination of Rb+ and Cs+ takes place both at OH groups and at the O atoms of the glucopyranosyl ring in the CD tori (Figure 2, right). This strong coordination, in cooperation with the geometrically favourable
- (left) and the 2:1 (right) complexes, showing the positions of K+ cations and Au(CN)2− anions as well as the relative dispositions of the α-CD tori. Adapted with permission from [49], Liu, W.; Jones, L. O.; Wu, H.; Stern, C. L.; Sponenburg, R. A.; Schatz, G. C.; Stoddart, J. F. Supramolecular gold
- . C skyblue, O red, Br brown, Au yellow. (c) Schematic illustration of the mechanism leading to precipitation (named “supramolecular polymerisation” by the authors) after adding various additives to the solution of β-CD and [AuBr4]− anions. Reproduced from [51] (© 2023 H. Wu et al., published by
Supramolecular assembly of hypervalent iodine macrocycles and alkali metals
Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87
- bonding is characterized as those interactions that involve intermolecular hypervalent connections with lengths shorter than the sum of the van der Waals radii between a heavy p-block element and an electron-pair donor (typically O, N, S, or halogen) [15]. Secondary I···O interactions have been found to
Recent advances in synthetic approaches for bioactive cinnamic acid derivatives
Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85
- methodologies based on the functional groups of cinnamic acid reported in the last five years: modifying the carboxyl group can involve several pathways, such as O/N-acylation, oxidative acylation, alkenyl/alkynyl carboxylation, and other reactions. Altering the double bond can be approached through double-bond
- these derivatives, this study aims to offer direct synthetic guidance and important insights into the rational design of novel cinnamate molecules with promising potential as future drug candidates. The reaction mechanisms will be discussed briefly. 2 Carboxyl group functionalization 2.1 O/N-acylations
- 2.1.1 Stoichiometric reagents: Anhydride formation is one reliable method to activate the carboxylic group of cinnamic acid. For instance, in 2020, Longobardo and DellaGreca utilized isobutyl chloroformate in water to construct an O-protected amide derivative 2 of hydroxycinnamic acid 1 with an
Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts
Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84
- carbon nanomaterials category in view of their stability, water affinity/dispersibility, and low toxicity [1][2][3][4]. Such nanomaterials significantly absorb in the 280–350 nm region due to a wide range of π–π* (C=C) and n–π* (C=O) transitions in both the core and on the surface of the particles. CDs
- * transition of the sp2 C=C conjugated system), 265–280 nm (in turn ascribed to the n–π* transition of the C=O group on the surface), and 350–360 nm (due to the n–π* transition of defects states). The spectra of both doped and undoped CDs obtained from citric acid are mainly comparable (see Figure 1), with a
Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline
Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79
- Pharmaceuticals Plc., Directorate of Drug Substance Development, P. O. Box 100, Keresztúri út 30-38, H-1475 Budapest, Hungary Department of Organic Chemistry, Faculty of Pharmacy, Semmelweis University, Hőgyes Endre utca 7, H-1092 Budapest, Hungary Center for Pharmacology and Drug Research & Development
Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes
Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78
- regioselective, diastereoselective, and metal-free protocol for alkene amino-hydroxylation, which compared favorably to prior art in this area [25][26][27][28][29][30][31][32]. Naturally, we wondered if other O-nucleophiles were competent in the ring-opening of the aziridinium intermediate. Indeed, almost all
Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts
Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76
- computational study to design new PCs to be employed in atom transfer radical polymerization (O-ATRP) [17]. Notably, the sulfur-based structure 2 showed excellent performance for this transformation. One year later, the same research group reported its use in a reversible addition-fragmentation chain-transfer
Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines
Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74
- involving the Ugi reaction between arylglyoxals 1, benzylamines 2, o-azidobenzoic acid (3), and cyclohexyl isocyanide (4a), followed by a triphenylphosphine-promoted tandem Staudinger/aza-Wittig cyclization (Scheme 1a) [33]. The overall strategy was enabled by the presence of an azide group in the
- trifluoromethyl and nitro groups. Furthermore, substrates 15m–o derived from aliphatic amines, also performed well, furnishing pyrazolodiazepines 16m–o in up to 89% yield. The structure of 16m, a representative compound of this series, was confirmed through single-crystal X-ray diffraction (scXRD) analysis
Recent advances in controllable/divergent synthesis
Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73
- , thereby offering unprecedented control over chemo-, regio-, and stereoselectivity parameters in catalytic manifolds. In 2015, the Jiang group developed a palladium-catalyzed regioselective three-component C1 insertion reaction (Scheme 1) [19]. In this reaction, an o-iodoaniline 1, phenylacetylene, and
- carbon monoxide were used as starting materials, and two natural product frameworks of phenanthridone and acridone alkaloids could be selectively obtained by controlling ligands. The reaction of o-iodoaniline with in situ-generated arynes under CO atmosphere under ligand-free conditions selectively
- intermediates Int-53 or Int-53'. Reductive elimination of Int-53 or Int-53' regenerates Pd(0) and produces intermediate 55. With the assistance of the base K2CO3, the ten-membered silacycle 55 undergoes rapid ring contraction via cleavage of two Si–O bonds and formation of one Si–O bond, leading to 56 and Int
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