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Search for "addition" in Full Text gives 3219 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

  • Thierry Milcent,
  • Pascal Retailleau,
  • Benoit Crousse and
  • Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

Graphical Abstract
  • intramolecular Michael addition. Preliminary conformational studies on tripeptides including this scaffold in the central position show an extended conformation in solution (NMR) and in the solid state (X-ray). Keywords: fluoroalkyl groups; heterocycles; hydrazino acids; peptides; tetrahydropyridazines
  • on an intramolecular Michael addition carried out in DMF and catalyzed by 10% of potassium carbonate. As previously observed [37], under these conditions, the 5-endo-trig cyclization was selective and the lactam resulting from the 5-exo-trig cyclization was not observed. Furthermore, in the case of
  • strategy, the control of the stereoselectivity of the intramolecular aza-Michael addition could be envisaged with various chiral catalysts in further studies. These heterocyclic hydrazino acids, when incorporated into the peptidic structure, appear to confer an extended conformation. These interesting
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Published 04 Dec 2024

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

  • Lucía Campos-Prieto,
  • Aitor García-Rey,
  • Eddy Sotelo and
  • Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

Graphical Abstract
  • [3]. These aspects are aligned with the goal of addressing concerns related to the generation of environmentally hazardous waste [4]. In addition, this type of reaction allows for the efficient discovery of low molecular weight compounds. As a result, most of these compounds are drug-like according
  • benzodioxepinones 12 in all cases (Scheme 11). The synthesized compounds demonstrated excellent drug-like features. Parkinson disease (PD) Knoevenagel–Michael addition/cyclization (MCR 3 + 2): Sirtuins, a group of enzymes that rely on NAD+ to function as protein deacetylases, have garnered attention across multiple
  • a multicomponent reaction to obtain SIRT2 inhibitors (Scheme 12). The authors suggest a Knoevenagel condensation approach between isatin derivatives and ethyl cyanoacetate, followed by a Michael addition with C–H activated carbonyl compounds and intramolecular cyclization [50]. They synthesized 45
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Published 03 Dec 2024

Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF5- and CF3SF4-containing [2]staffanes

  • Jón Atiba Buldt,
  • Wang-Yeuk Kong,
  • Yannick Kraemer,
  • Masiel M. Belsuzarri,
  • Ansh Hiten Patel,
  • James C. Fettinger,
  • Dean J. Tantillo and
  • Cody Ross Pitts

Beilstein J. Org. Chem. 2024, 20, 3134–3143, doi:10.3762/bjoc.20.259

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  • truncated after incorporation of two bicyclopentane (BCP) units. Synthetic and computational studies suggest this phenomenon can be attributed to alternating radical polarity matching. In addition, single-crystal X-ray diffraction (SC-XRD) data reveal structurally interesting features of the CF3SF4
  • bicyclopentyl radical philicities. In addition, we demonstrate that similar reaction conditions can be applied to the synthesis of the analogous CF3SF4-containing [2]staffane (CF3SF4-BCP-BCP-Cl, 3). Finally, we examined compound 3 by SC-XRD and found that it undergoes a phase transition as a function of rate of
  • energy profile of the radical chain propagation sequence was computed at the PWPB95-D4/def2-QZVPP//PCM(Et2O)-ωB97X-D/def2-TZVP level of theory [51][52][53][54][55][56][57][58] (Figure 2). Following addition of an SF5 radical to 1 to form INT1, a Cl atom could be abstracted from SF5Cl via TS1 to form 4 or
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Published 29 Nov 2024

Hypervalent iodine-mediated intramolecular alkene halocyclisation

  • Charu Bansal,
  • Oliver Ruggles,
  • Albert C. Rowett and
  • Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

Graphical Abstract
  • structures. HVI reagents are characterized by their diverse reactivity as oxidants and electrophilic reagents. In addition, they are inexpensive, non-toxic and considered to be environmentally friendly. An important application of HVI reagents is the synthesis of halogenated cyclic compounds, in particular
  • were synthesised in moderate to excellent yields and enantiomeric excesses. In addition to the synthesis of 6-membered rings, 7-membered hexenamines 7 were synthesised. To the authors’ surprise, reaction conditions for the synthesis of β-fluorinated piperidines 6 afforded no product. The reaction
  • instead proceeded with addition of dichloro(pyridine-2-carboxylato)gold(III) complex in combination with silver triflimide, AgNTf2. A range of β-fluoroazepanes 7 were successfully synthesised with high enantiomeric purity in good yields. A mechanism for the synthesis of β-fluorinated piperidines was
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Published 28 Nov 2024

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

  • Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

Graphical Abstract
  • well as transition and rare-earth metals [32][33]. There are many comprehensive reviews covering these two areas along with the connection of these ligands to supramolecular and medicinal chemistry [34][35][36]. In addition, calix[4]pyrroles, due to the presence of four accessible inner NHs and well
  • addition of furan-based silyloxydiene synthons to a variety of achiral aldehydes using four different calix[4]pyrrole macrocycles (3, 4, 11, and 12) as organocatalysts (Figure 3) [38]. These calixpyrrole macrocycles acted as hydrogen-bond donors, activating substrate aldehydes through hydrogen-bonding
  • catalytically inactive, but the mixture of CuCl (7 mol %) and calix[4]pyrrole (14 mol %) resulted in a 74% yield of 1-tosyl-2-phenylaziridine (24). Considering the significant shift (from 7.48 to 9.98) in the N–H signal of calix[4]pyrrole after the addition of CuCl, the authors suggested that calix[4]pyrrole
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Published 27 Nov 2024

Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

  • Cesia M. Aguilar-Morales,
  • América A. Frías-López,
  • Nadia V. Emilio-Velázquez,
  • Alejandro Islas-Jácome,
  • Angelica Judith Granados-López,
  • Jorge Gustavo Araujo-Huitrado,
  • Yamilé López-Hernández,
  • Hiram Hernández-López,
  • Luis Chacón-García,
  • Jesús Adrián López and
  • Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

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  • and resource optimization. In addition, all the target compounds were fully characterized using 1H and 13C NMR spectroscopy and HRMS. It is important to mention that this protocol cannot be considered a true one-pot synthesis, as it requires a solvent exchange between reaction steps (e.g., from
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Published 26 Nov 2024

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

  • Noble Brako,
  • Sreerag Moorkkannur Narayanan,
  • Amber Burns,
  • Layla Auter,
  • Valentino Cesiliano,
  • Rajeev Prabhakar and
  • Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

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  • , University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146-0431, USA 10.3762/bjoc.20.255 Abstract Distilled propargyltrichlorosilane with >99% isomeric purity was prepared for the first time, and its asymmetric catalytic regiospecific addition reaction to aldehydes was developed through a
  • . Accordingly, the development of efficient access to optically active chiral α-allenic alcohols continues to be of significant interest in organic chemistry [11][12][13]. The asymmetric catalytic addition of allenylation reagents to aldehydes provides direct access to chiral α-allenic alcohols in an
  • enantioenriched form [11][12]. However, such metal/metalloid reagents and the corresponding metal catalyst-bound intermediates often equilibrate between possible regioisomeric forms and can undergo both, SE2 and SE2’ addition reactions, resulting in a mixture of homopropargylic alcohols and α-allenic alcohols [14
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Published 25 Nov 2024

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

  • Robin Schulte,
  • Dustin Schade,
  • Thomas Paululat,
  • Till J. B. Zähringer,
  • Christoph Kerzig and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

Graphical Abstract
  • elemental analysis. All products showed the characteristic 1H NMR spectroscopic signals of norbornadienes, in particular two signals at ca. 2.10 ppm and 2.20 ppm (7-CH2) and two broad singlets between 3 and 4 ppm (bridgehead 1- and 4-CH). In addition, typical 13C NMR shifts of the aryl-substituted
  • derivatives during the photoreaction, whereas the blue-shifted maximum of the photoproduct was formed. In addition, isosbestic points were observed for the derivatives 1h (A), 1i (B), 1k (D), and 1l (E). The irradiations of the derivatives 1h, 1i, 1k, and 1l were stopped once no more changes of the absorbance
  • that the triplet energy of 1i is significantly lower than 2.4 eV and even triplet sensitizers with lower triplet energies than that of [Ru(phen)3](PF6)2 could be employed for this reaction, which might even allow red light-driven switching. In addition to these kinetic studies, the photoisomerization
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Published 21 Nov 2024
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  • substitution/addition reactions became the standard for end-capping reactions, although a transition metal–catalyzed cross-coupling reaction has also been used to synthesize CD-based rotaxane. Typically, water-soluble components are prepared, after which the Suzuki coupling reaction in water is used to
  • depended on the cavity size, the same as small-molecule inclusion. For example, PEG forms stable pseudopolyrotaxane structures with α, β, and γ-CDs, although polypropylene glycol (PPG) only forms a stable pseudopolyrotaxane structure with β-CD [41]. In addition to these linear polymer chains, various types
  • synthesis, Harada and co-workers reported the end-capping reaction based on nucleophilic substitution by the amino groups on axle ends (Scheme 2) [43]. Similarly, other highly efficient reactions have been performed as end-capping reactions to produce polyrotaxane [13][14][15]. In addition to the simple
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Published 19 Nov 2024

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

  • Anastasia I. Ershova,
  • Sergey V. Fedoseev,
  • Konstantin V. Lipin,
  • Mikhail Yu. Ievlev,
  • Oleg E. Nasakin and
  • Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

Graphical Abstract
  • caused a blue shift of the maximum at 511 nm, and a new maximum in the region of 380–400 nm appeared in the absorption spectra. The intensity of the short-wavelength band also increased upon addition of trifluoroacetic acid. At the same time, a second band centered at 440 nm also appeared in the emission
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Published 19 Nov 2024

Tailored charge-neutral self-assembled L2Zn2 container for taming oxalate

  • David Ocklenburg and
  • David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

Graphical Abstract
  • positively charged or charge-neutral, is their metal-driven self-assembly. Unfortunately, this can also be their Achilles' heel, as the underlying coordination bonds are fragile compared to covalent bonds. For example, metallocages can easily break apart by the addition of competitive anions which are highly
  • determined by NMR (see Supporting Information File 1, Figures S7, S9, S11, S13, S15, and S17). 1H NMR dicarboxylate binding studies were carried out with oxalate (C22−) and longer variants C(2+n)2− up to adipate (with n = 4). Oxalate addition to [L2Zn2] results in an intermediate exchange with broadened NMR
  • guests and competition experiments. 1H NMR titrations with malonate, succinate, glutarate, and adipate showed no clean binding (formation of mixtures) upon addition of these guests as TBA salt to [L2Zn2], with broad regions and multiple sets of signals persisting even after the addition of a large excess
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Published 18 Nov 2024

Advances in radical peroxidation with hydroperoxides

  • Oleg V. Bityukov,
  • Pavel Yu. Serdyuchenko,
  • Andrey S. Kirillov,
  • Gennady I. Nikishin,
  • Vera A. Vil’ and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

Graphical Abstract
  • range of polymers [1]. They are also applied as curing, hardening and crosslinking agents [2]. Global demand for organic peroxides is expected to increase as the use of engineered plastics increases and production capacity is expanded. In addition, the need for polymers is expected to increase due to
  • mainly include: nucleophilic addition or nucleophilic substitution with H2O2 or ROOH [17][18], autoxidation with O2, pericyclic reactions of unsaturated bonds with O3 or O2, and metal-catalyzed peroxidation (Isayama–Mukaiyama hydrosilylperoxidation [19][20], for example) [21][22][23]. As the topic is
  • and tert-butylperoxy moiety (Scheme 33) [89]. The mechanism of the process is probably based on the formation of radical species A and B, which disproportionate to form the intermediate C. Sequential addition of sulfonyl and tert-butylperoxy radicals to the double bond of intermediate C leads to
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Published 18 Nov 2024

gem-Difluorovinyl and trifluorovinyl Michael acceptors in the synthesis of α,β-unsaturated fluorinated and nonfluorinated amides

  • Monika Bilska-Markowska,
  • Marcin Kaźmierczak,
  • Wojciech Jankowski and
  • Marcin Hoffmann

Beilstein J. Org. Chem. 2024, 20, 2946–2953, doi:10.3762/bjoc.20.247

Graphical Abstract
  • , we observed a striking illustration of this phenomenon. A Michael addition involving gem-difluorovinyl and trifluorovinyl acceptors was successfully achieved, demonstrating high stereoselectivity. This selectivity was further elucidated through theoretical calculations. Using this methodology, a
  • series of new α,β-unsaturated amides, both fluorinated and nonfluorinated, were synthesized. Keywords: gem-difluorovinyl Michael acceptors; Michael addition; trifluorovinyl Michael acceptors; α,β-unsaturated amides; Introduction The Michael reaction, characterized by the addition of stable carbon
  • advancements have broadened the scope of Michael donors and acceptors to encompass fluorine-containing compounds, enhancing the reaction's utility in synthesizing fluorinated derivatives [7][8]. Shibata and colleagues pioneered the use of fluorinated Michael donors, notably achieving enantioselective addition
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Published 15 Nov 2024

4,6-Diaryl-5,5-difluoro-1,3-dioxanes as chiral dopants for liquid crystal compositions

  • Maurice Médebielle,
  • Peer Kirsch,
  • Jérémy Merad,
  • Carolina von Essen,
  • Clemens Kühn and
  • Andreas Ruhl

Beilstein J. Org. Chem. 2024, 20, 2940–2945, doi:10.3762/bjoc.20.246

Graphical Abstract
  • from neat chiral mesogens, or through the addition of a chiral dopant to an achiral nematic liquid crystal [5][6]. The ability of the dopant to induce chirality in the nematic phase is defined as the helical twisting power [HTP; β = (pc)−1; with p the helical pitch and c the molar concentration]. The
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Published 14 Nov 2024

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

Graphical Abstract
  • formation of the Nu–Ar product and aryl iodide [21]. Second, the arylation can take place in the presence of a metal catalyst via oxidative addition, followed by reduction elimination [48][49]. Thirdly, it proceeds through a ligand-coupled arylation which involves a five-membered transition state to yield
  • additives. An efficient conversion was detected when the substrate contains electron-rich functionalities. In contrast, the yield dropped notably when the amines were substituted with electron-deficient functionalities. In addition, asymmetric diaryliodonium salts were examined, and the transfer of the aryl
  • compounds (Scheme 16) [68]. The novel iodine(III) intermediate was generated through nucleophilic substitution of a heteroatom nucleophile, which initiated the reaction. A subsequent aryl migration from the iodine to the heteroatom resulted in the formation of the arylated nucleophile. In addition to
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Published 13 Nov 2024

C–H Trifluoromethylthiolation of aldehyde hydrazones

  • Victor Levet,
  • Balu Ramesh,
  • Congyang Wang and
  • Tatiana Besset

Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242

Graphical Abstract
  • morpholine hydrazone derived from 4-nitrobenzaldehyde was selected as a model substrate (Table 1). The latter was engaged in a two-step process: 1) halogenation to provide the corresponding N,N-hydrazonoyl bromide, which will then undergo an anion metathesis upon the addition of AgSCF3 to the reaction
  • mixture. When the reaction was conducted in the presence of NBS in acetonitrile for 10 min, followed by the addition of AgSCF3, the desired product was isolated in 91% yield. A total selectivity for the formation of the Z isomer was observed as ascertained by 2D NMR (for more details, see Supporting
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Published 12 Nov 2024

Synthesis of pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine derivatives via isocyanide-based multicomponent reactions

  • Marzieh Norouzi,
  • Mohammad Taghi Nazeri,
  • Ahmad Shaabani and
  • Behrouz Notash

Beilstein J. Org. Chem. 2024, 20, 2870–2882, doi:10.3762/bjoc.20.241

Graphical Abstract
  • addition to the application of isocyanides in a variety of MCRs, one of the unique reactions involves the formation of zwitterions from isocyanides upon reaction with acetylene and active olefin compounds such as alkyl acetylenedicarboxylates and gem-diactivated olefins. Due to having nucleophilic and
  • increase and the electron-donating substituents led to a decrease in the reaction efficiency (Scheme 3, 4a–k). In addition, benzothiazepine was used in this protocol and the corresponding pyrrole-fused benzothiazepine was obtained with a yield of 73% (Scheme 3, 4l). Also, various isocyanides were suitable
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Published 11 Nov 2024

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

  • Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

Graphical Abstract
  • [12][13]. In addition, there are more and more applications in the field of medicinal chemistry, especially for the treatment of cancer [14][15]. In the course of the renewed interest in the chemistry of indigo, indirubin, and isoindigo in the field of cancer research, N-glycosides of these compounds
  • steps from indigo (1a). The reaction of 1a with potassium permanganate afforded product 12 which was transformed to dehydroindigo (13) by pyridine-mediated elimination of acetic acid. The reaction of 13 with tetra-O-trimethylsilyl-ʟ-rhamnopyranose (4b) in the presence of trimethylsilyl iodide, addition
  • of n-propyl mercaptane with subsequent addition of acetic anhydride, pyridine and KHF2 afforded indigo-N-rhamnoside 5c as a 2:1 mixture of α/β-anomers. The relatively low yield is a result of side reactions and decomposition, due to the rather unstable nature of the product. The reaction of 5c with
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Published 08 Nov 2024

Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides

  • Baptiste Leroux,
  • Alexis Beaufils,
  • Federico Banchini,
  • Olivier Jackowski,
  • Alejandro Perez-Luna,
  • Fabrice Chemla,
  • Marc Presset and
  • Erwan Le Gall

Beilstein J. Org. Chem. 2024, 20, 2834–2839, doi:10.3762/bjoc.20.239

Graphical Abstract
  • alkyl iodides [24]. It was indeed noticed that the reactivity of primary iodides in the multicomponent carbonyl alkylative amination (CAA) reaction was quite sluggish compared to the secondary counterparts. In addition, primary alkyl bromides were found to be almost inactive in the process. Therefore
  • . In addition, whereas tert-butylzinc iodide was efficient in the multicomponent coupling (99% yield), tert-butylzinc bromide led to a very low yield (16% 5kaa). The coupling presented some other limitations. It was not possible to carry out the reaction when a primary amine was employed. In addition
  • significant assets associated to the use of alkyl bromides, which are more easily prepared (or commercially available), less costly, and more stable than the corresponding alkyl iodides. In addition, the reaction can be conducted in commercial THF or 2-MeTHF and without special precautions. We also found a
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Published 07 Nov 2024

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

  • Kento Iwai,
  • Akari Hikasa,
  • Kotaro Yoshioka,
  • Shinki Tani,
  • Kazuto Umezu and
  • Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

Graphical Abstract
  • ] because of their easily modifiable dipeptide frameworks. Several methods exist for accessing PCPAs, such as the amination of 1-halo-1-alkynes [16][17], tandem reactions of α-imino esters with nucleophiles and electrophiles [18], and the nucleophilic addition of an acetylide to α-carbonylated N-acylimines
  • derivative has been employed (Scheme 1) [13][14]. Recently, we have demonstrated that the central carbonyl group of DEMO is highly electrophilic, facilitating the nucleophilic addition of less reactive reagents such as acid amides [23][24][25][26]. When the reaction was conducted in the presence of acetic
  • anhydride, the intermediately formed hemiacetal underwent acetylation, leading to N,O-acetals 1. In this method, an acid amide can be used as an amine masked with an acyl group. Subsequent elimination of acetic acid occurred to afford 2 in situ upon treatment with a base, enabling nucleophilic addition with
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Published 06 Nov 2024

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

  • Parvathy Mini,
  • Michael R. Grace,
  • Genevieve H. Dennison and
  • Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

Graphical Abstract
  • an antenna chromophore and a receptor for Cu2+ ions; the Cu2+ complex was shown to be a chemosensor for the detection of aqueous hydrogen sulfide. The chemosensor exhibited significant reversibility over multiple cycles, observed with the sequential addition of Na2S followed by Cu2+ ions. The limit
  • for the detection of both gaseous and/or aqueous H2S are shown in Figure 1 [12][16][17]. These sensors all function via the copper sequestration mechanism, where upon addition of hydrogen sulfide to the quenched bimetallic species, luminescence modulation occurs. In our quest for highly selective
  • ). Response of Tb.1 with Cu2+ ions The addition of excess Cu2+ ions to Tb.1 was expected to result in complete saturation of emission signals. However, upon the titration of Cu2+ ions to 5 μM Tb.1 (10 mM Tris-HCl buffer containing 5% DMSO, pH 7.4), emission signal saturation was not observed until 5
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Published 05 Nov 2024

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

  • Dmitriy Yu. Vandyshev,
  • Daria A. Mangusheva,
  • Khidmet S. Shikhaliev,
  • Kirill A. Scherbakov,
  • Oleg N. Burov,
  • Alexander D. Zagrebaev,
  • Tatiana N. Khmelevskaya,
  • Alexey S. Trenin and
  • Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

Graphical Abstract
  • polyfunctional precursors 1, 2, and 3, two pathways are theoretically possible (Scheme 2 and Scheme 3). The first one involves the N-nucleophilic Michael addition to the activated multiple bond of the imide, leading to the formation of linear intermediates 6 or 8 (pathways A1 and B1) at the expense of the endo
  • in Scheme 3). In addition, clearly distinguishable cross-peaks between the protons of the CH2-5 group and both endo and exo-carbonyl groups are observed. This allowed us to explicitly exclude from the analysis structures 13 and 15, which contain both endo-methylene groups, as part of a
  • 6a, which undergoes subsequent cyclization steps more favorably, leading to the formation of the target product 4a (∆G = −3.02 kcal/mol). This suggests that the first step of intermediate formation is the critical one. It is also noteworthy that the Michael addition via intermediate 6a is an
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Published 05 Nov 2024

C–C Coupling in sterically demanding porphyrin environments

  • Liam Cribbin,
  • Brendan Twamley,
  • Nicolae Buga,
  • John E. O’ Brien,
  • Raphael Bühler,
  • Roland A. Fischer and
  • Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

Graphical Abstract
  • examples are azide-porphyrin derivatives reported by Flanagan et al. [43]. Here, five crystal structures were obtained of meso-para-phenyl arm-extended porphyrins (26, 27, 28, 29, 33) and two crystal structures for meso-meta-phenyl derivatives 36 and 37. In addition, single crystal structures of 11 and 46
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Published 04 Nov 2024

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

  • Yuta Kabumoto,
  • Eiichiro Yoshimoto,
  • Bing Xiaohuan,
  • Masato Morita,
  • Motohiro Yasui,
  • Shigeyuki Yamada and
  • Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

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  • published that the asymmetric conjugate addition of 4-methylphenylboronic acid towards (E)-5-bromo-4,4,5,5-tetrafluoro-1-phenyl-2-penten-1-one (8) in the presence of a rhodium catalyst coordinated with (S)-BINAP gave the corresponding Michael adduct 9 in 94% enantiomeric excess (reaction 2, Scheme 1) [22
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Published 01 Nov 2024

Copper-catalyzed yne-allylic substitutions: concept and recent developments

  • Shuang Yang and
  • Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

Graphical Abstract
  • -enynes with dimethylamine moiety (Scheme 11, 6x and 6y). In addition to tetramethylenediaminomethane, other tetraalkyldiaminomethanes can also be used as supplants of dialkylamines, leading to products with dialkylamine units with high yields and enantioselectivities (Scheme 11, 6a, 6g, 6i and 6z
  • ester was also a suitable substrate for the reaction (Scheme 20, 20p). In addition, the presence of substituents such as hydroxy or chlorine groups on the anthrones had no impact on the reaction (Scheme 20, 20q–t). Chiral coumarins, renowned for their bioactive properties, form the cornerstone of
  • radical-involved mechanism. In addition, a positive nonlinear relationship between the product and ligand indicated that the dinuclear copper is the active catalyst, which was also proved by single crystal X-ray analysis. However, kinetic experiments showed the reaction is first-order on copper, implying
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Published 31 Oct 2024
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