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Search for "complexes" in Full Text gives 1156 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Computational toolbox for the analysis of protein–glycan interactions

  • Ferran Nieto-Fabregat,
  • Maria Pia Lenza,
  • Angela Marseglia,
  • Cristina Di Carluccio,
  • Antonio Molinaro,
  • Alba Silipo and
  • Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

Graphical Abstract
  • –ligand complexes, and analyse MD outcomes. Moreover, selected case studies have been reported to highlight the importance of computational tools in studying protein–glycan systems, revealing the capability of these tools to provide valuable insights into the binding kinetics, energetics, and structural
  • using the doglycans.py tool. (https://bitbucket.org/biophys-uh/doglycans/). 2. Glycam-Web carbohydrate builder [50]: Free online web-service that gives the possibility to model the 3D structures of molecules and complexes containing carbohydrates starting from monosaccharide building blocks, being also
  • study protein–ligand complexes Detailed investigations of protein–ligand interactions, combining experimental and computational methods, provide an indispensable basis to depict holistic pictures of molecular complexes allowing to modulate them at will. The computational approach involves i) predicting
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Published 22 Aug 2024

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

  • Ignaz Betcke,
  • Alissa C. Götzinger,
  • Maryna M. Kornet and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

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  • , 3,4,5-substituted pyrazoles 5 are formed (Scheme 2) [45]. The Lewis acid catalyst accelerates the reaction via participation in the formation of β-diketonate complexes. Other carbonyl compounds suitable for pyrazole synthesis are 2,4-diketoesters 13. These intermediates can be prepared from diethyl
  • solution and in the solid state [127]. Furthermore, even sugar-functionalized pyrazoles have been accessed by this approach [128], and it was readily implemented in a continuous flow reactor [129]. Besides traditional Sonogashira catalyst systems, highly reactive and reusable immobilized Pd-complexes, such
  • aliphatic alkynes, copper iodide is necessitated as a co-catalyst [141]. In addition to classic Sonogashira catalysts, phosphane-free palladium [Pd(NN)] chelate complexes can also be used, which promote excellent regioselectivity [142]. A variation of the reaction is possible with Mo(CO)6 as a carbon
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Published 16 Aug 2024

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

  • Liubov V. Sokolenko,
  • Taras M. Sokolenko and
  • Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

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  • meso form in high combined yield (90%, Scheme 16) [94]. The product was used as a ligand for the preparation of transitional metal carbonyl complexes. The addition reaction of trichlorofluoromethane (CFC-11) to 1,2-difluoroethylene in the presence of aluminum chloride under pressure was described [51
  • transitional metal complexes with 1,2-difluoroethylene as a ligand should be mentioned [109][110][111]. Conclusion In conclusion, our literature analysis demonstrated that radical processes are most typical for 1,2-difluoroethylene, while examples of electrophilic reactions are scarce, and nucleophilic
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Published 12 Aug 2024

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

  • Pengcheng Lu,
  • Luis Juarez,
  • Paul A. Wiget,
  • Weihe Zhang,
  • Krishnan Raman and
  • Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

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  • negligible. These data suggest that deprotonation occurs prior to alkylation and that deprotonation of either indazole tautomer leads to anions of identical or highly similar energy. Furthermore, as seen in Figure 4, a total, five coordinated complexes were found to be at least 4.5 kcal/mol more stable than
  • the uncoordinated anion when calculated as isolated structures. When the calculation is performed as a reaction of E and Z-enolates with Cs+ ion, two coordinated complexes 6(N-H)NNCs-E and-6(N-H)NOCs-Z are exergonically formed by 9.7 and 10.9 kcal/mol, respectively. We then searched for transition
  • identified as 6(N-H) (bottom). DFT-calculated Cs+-coordinated complexes with different enolate forms of 6(N-H) calculated as isolated compounds (top) and calculated intermediates of the reactions of 6(-N1H-Z) and 6(-N1H-E) with Cs+ (bottom). DFT-calculated reaction coordinate diagram for the reaction of 6
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Published 09 Aug 2024

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

  • Maria-Paula Schröder,
  • Isabel P.-M. Pfeiffer and
  • Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

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  • can also be employed to mimic non-ribosomal peptides [12][13], since it is substantially more challenging to engineer non-ribosomal peptide synthetase (NRPS) pathways. Non-ribosomal peptides are often produced by giant multi-modular enzyme complexes (type I NRPS) and they are most commonly involved in
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Published 18 Jul 2024

Benzylic C(sp3)–H fluorination

  • Alexander P. Atkins,
  • Alice C. Dean and
  • Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

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  • in this section, radical-based approaches enable the fluorination of a diverse range of benzylic substrates, which rely on the use of FAT reagents, such as Selectfluor, NFSI or copper fluoride complexes. Nucleophilic benzylic C(sp3)–H fluorination Nucleophilic fluorine sources can be more economical
  • transition-metal complexes to generate metal–fluorine bonds capable of FAT to benzylic substrates. In a follow-up to their work using electrophilic fluorine sources for palladium-catalysed benzylic C–H fluorination (Figure 5), the Sanford group demonstrated in 2012 the same transformation could be achieved
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Published 10 Jul 2024

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

  • Yukang Wang,
  • Yan Yao and
  • Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

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  • invention of cooperative catalysis with electrochemical transition metal catalysis, which generally has mild oxidation potential for the generation of persistent radicals in the form of nucleophile-bound metal complexes. We and other groups have successfully applied this reaction design to enantioselective
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Published 03 Jul 2024

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

  • Yu Fan,
  • Ahmed El Rhaz,
  • Stéphane Maisonneuve,
  • Emilie Gillon,
  • Maha Fatthalla,
  • Franck Le Bideau,
  • Guillaume Laurent,
  • Samir Messaoudi,
  • Anne Imberty and
  • Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

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  • crystalline complexes. The protein is represented by orange ribbon, His53 by lines, and calcium by green sphere. Synthesis of photoswitchable LecA inhibitors. Reagents and conditions: (i) DMC, Et3N, H2O, −10 °C to rt, 8 h, 50% for 7, 40% for 10; (ii) BrCH2CH2NHBoc, K2CO3, DMF, 60 °C, 15 h, 91% for 8, 80% for
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Published 03 Jul 2024

Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain

  • Changjun Xiang,
  • Shunyu Yao,
  • Ruoyu Wang and
  • Lihan Zhang

Beilstein J. Org. Chem. 2024, 20, 1476–1485, doi:10.3762/bjoc.20.131

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  • : bioinformatics; conserved motifs; ketoreductase; polyketide synthase; stereocontrol; Introduction Type I modular polyketide synthases (PKSs) are large enzyme complexes that play a crucial role in the biosynthesis of bacterial polyketides, including many important clinical drugs such as erythromycin (antibiotic
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Published 02 Jul 2024

Rapid construction of tricyclic tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine via isocyanide-based multicomponent reaction

  • Xiu-Yu Chen,
  • Ying Han,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2024, 20, 1436–1443, doi:10.3762/bjoc.20.126

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  • carbon atom of isocyanide has both a lone electron pair and empty orbitals, so it has outstanding electrophilic and nucleophilic reactivity. At the same time, isocyanide also has good coordination ability to coordinate with metals to form diverse metal complexes [1][2][3]. Therefore, isocyanides have
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Published 28 Jun 2024

A comparison of structure, bonding and non-covalent interactions of aryl halide and diarylhalonium halogen-bond donors

  • Nicole Javaly,
  • Theresa M. McCormick and
  • David R. Stuart

Beilstein J. Org. Chem. 2024, 20, 1428–1435, doi:10.3762/bjoc.20.125

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  • engage in halogen-bonding interactions [29][30]. In this work, a series of halogen-bond donor molecules and their halogen bond complexes with chloride anion were optimized at the M062x/6-311+G(d) level of theory [31] with def2-tzvpp used for iodine and astatine, and with SMD solvation in tetrahydrofuran
  • kcal/mol). The X---Cl distance calculated for the halogen-bonding complexes 41 and 45 of phenyl chloride (25) and mesityl chloride (29) with chloride anion were 3.85 and 3.71 Å, respectively. These values are larger than the sum of the van der Waals radii (3.5 Å) for two chlorine atoms [36] and
  • ---Cl distance for halogen-bond complexes 9–24, 42–44, and 46–56; representative examples are shown in Scheme 4. As a reference we considered the trend in X–Cl covalent bond distance with respect to the van der Waals radii of X [36], and we observed a linear trend with a positive slope (Scheme 4b, grey
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Published 27 Jun 2024

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

  • Mithu Roy,
  • Bitan Sardar,
  • Itu Mallick and
  • Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

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  • . Different photocatalysts, such as transition metal complexes [23][24], organic dyes [25], and semiconductors [26], can be employed for visible-light-induced chemical processes. The choice of photocatalyst depends on the specific requirements of the catalytic process, including the type of reaction, the
  • , such as iridium complexes or organic dyes, and activating agents, including dimethyl dicarbonate (DMDC) and PPh3. Redox-active esters are created when activating agents and carboxylic acids react. These esters can then be reduced using a photoredox catalyst to produce the acyl radical. In 2019, Doyle
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Published 14 Jun 2024

Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor

  • Kazuyuki Sato,
  • Satoki Teranishi,
  • Atsushi Sakaue,
  • Yukiko Karuo,
  • Atsushi Tarui,
  • Kentaro Kawai,
  • Hiroyuki Takeda,
  • Tatsuo Kinashi and
  • Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 1341–1347, doi:10.3762/bjoc.20.118

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  • Integrins are transmembrane heterodimers, each consisting of α and β subunits, that mediate cell–cell and cell–matrix adhesion involved in normal and pathological processes. Bidirectional signaling through integrins regulate cell shape, motility, and cell cycle progression [23]. The integrin complexes are
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Published 12 Jun 2024

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

  • Guoqing Cheng and
  • Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

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  • ) acetylacetonate, the nanobracket 4b and HiPco SWNTs were bath-sonicated for 9 h in 2-propanol. Meanwhile, 4b is assumed to form complexes with SWNTs. After copper(II) acetylacetonate was added to the mixture, the cyclic Cu-nanobrackets 1b would be formed to interlock SWNTs with appropriate diameters during
  • and their complexes with interlocking structures, respectively, after the geometry optimization with the GFN2-xTB method. The 45 different kinds of SWNTs with length of ≥3.0 nm and diameter range of 0.7–1.2 nm are chosen for the calculation (Table S1, Supporting Information File 1). The relationship
  • between the SWNT diameter and Ebind is shown in Figure 6a. Even though the Ebind magnitude of van der Waals-dominated complexes of conjugated π-systems (e.g., fullerenes) are sometimes overestimated in the calculation by GFN2-xTB [16], the Ebind can be compared in the SWNT complexes with Cu-nanobrackets
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Published 05 Jun 2024

Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

  • Alina Paffen,
  • Christopher Cremer and
  • Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

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  • 88 ‘‘Cooperative effects in homo and heterometallic complexes’’ (http://3MET.de) is acknowledged for generous financial support.
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Published 04 Jun 2024

Synthesis and physical properties of tunable aryl alkyl ionic liquids based on 1-aryl-4,5-dimethylimidazolium cations

  • Stefan Fritsch and
  • Thomas Strassner

Beilstein J. Org. Chem. 2024, 20, 1278–1285, doi:10.3762/bjoc.20.110

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  • weakly coordinating anions like bis(trifluoromethylsulfonyl)imide [NTf2]− [25]. In addition, dicationic salts or anions containing metal complexes have been described [26][27]. Due to the numerous combinations of different anions and cations, ILs can also be described as designer solvents [28]. We
  • well known that the hydrogen atom at the C2 carbon atom of the imidazole core is more acidic as those in the C4/C5-position, where the methyl groups are expected to also have a significant effect on the molecular interactions. Platinum complexes using the 4,5-dimethylimidazole motif as a ligand were
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Published 31 May 2024

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

  • Johannes Rocker,
  • Till J. B. Zähringer,
  • Matthias Schmitz,
  • Till Opatz and
  • Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

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  • triplet reactivity of the Aza-H photocatalyst through spectroscopic measurements. The careful characterization of the versatile Aza-H photochemistry might contribute to the development of a new class of photoactive catalysts that can compete with traditional metal complexes and well-known organic
  • chromophores (as listed above). Results and Discussion A thorough understanding of the operation principles of a photocatalyst is essential for the development of improved catalysts and efficient photoreactions. To this end, the photochemical properties of photocatalysts such as metal complexes and organic
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Published 28 May 2024

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

  • Vishnu Selladurai and
  • Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

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  • the sodium complexes [M + Na]+, [2M + Na]+, and [3M + Na]+ (Figure S13, Supporting Information File 1). The mass spectrum of quinone 10 showed a peak for [M + H]+ (Figure S17, Supporting Information File 1). Reaction of methyl anthranilate with SeO2 After observing that unsubstituted aniline and
  • ). Similar to the 77Se NMR signals of isomeric diaryl diselenides 1 and 2, the symmetrical diaryl diselenide 12, having an amino group para to the selenium center in both aryl units, showed a downfield shift compared to isomer 11. The mass spectrum of oxamide 13 revealed peaks for the sodium complexes [M
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Published 27 May 2024

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

  • Mohd Farhan Ansari,
  • Atul Kumar Maurya,
  • Abhishek Kumar and
  • Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

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  • reactions allow the sustainable construction of C–C and C–N bonds using alcohols as hydrogen donors. In recent years, manganese complexes have been explored as efficient catalysts in these reactions. This review highlights the significant progress made in manganese-catalyzed C–C and C–N bond-formation
  • Milstein [17] in hydrogenation and dehydrogenation reactions with pincer-decorated manganese complexes, significant progress has been made in manganese catalysis [18][19][20]. Notably, well-defined low-valent diamagnetic manganese(I) complexes have been studied in many catalytic transformations, and
  • as hydrogen donors and alkylating agents. In general, low-valent manganese complexes are used as pre-catalysts in this reaction and are activated using a strong base to generate the active amido complexes, which in turn activate the alcohols. Then, the formed dehydrogenation products, such as
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Published 21 May 2024

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

  • Akanksha Ashok Sangolkar,
  • Rama Krishna Kadiyam and
  • Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

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  • /vinylheptafulvene, azobenzenes, tetracarbonyl(fulvalene)diruthenium complexes, norbornadiene/quadricyclane (NBD/QC), anthracenes, etc. exhibit a few promising properties for MOST applications [10][12][13]. However, these photoswitching couples still lack one or more important properties required in MOST systems and
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Published 13 May 2024

Carbonylative synthesis and functionalization of indoles

  • Alex De Salvo,
  • Raffaella Mancuso and
  • Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

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  • complexes are important for the synthesis of heterocyclic and non-heterocyclic compounds. In 2009, Arthuis and co-workers developed a new process for the synthesis of 2-aroylindoles and 2-heteroaroylindoles by a one-pot palladium-catalyzed domino reaction that involves an initial C,N-coupling followed by
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Published 30 Apr 2024

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

  • Arnaldo G. de Oliveira Jr.,
  • Martí F. Wang,
  • Rafaela C. Carmona,
  • Danilo M. Lustosa,
  • Sergei A. Gorbatov and
  • Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

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  • in the er. Pd(acac)2 and Pd(MeCN)2(OTs)2 were also tested without significant improvements. Despite the fact that palladium acetate slightly better performed as shown in Table 1, we decided to continue with palladium trifluoroacetate due to its higher reactivity in forming palladium complexes with N
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Published 29 Apr 2024

Monitoring carbohydrate 3D structure quality with the Privateer database

  • Jordan S. Dialpuri,
  • Haroldas Bagdonas,
  • Lucy C. Schofield,
  • Phuong Thao Pham,
  • Lou Holland and
  • Jon Agirre

Beilstein J. Org. Chem. 2024, 20, 931–939, doi:10.3762/bjoc.20.83

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  • modelling of glycoproteins and protein–carbohydrate complexes is pivotal in understanding the complex biochemical interactions that affect the physiological function of cells [1]. Any mechanistic analysis done with finely grained approaches such as QM/MM [2] relies heavily on the correctness of the starting
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Published 24 Apr 2024

Confirmation of the stereochemistry of spiroviolene

  • Yao Kong,
  • Yuanning Liu,
  • Kaibiao Wang,
  • Tao Wang,
  • Chen Wang,
  • Ben Ai,
  • Hongli Jia,
  • Guohui Pan,
  • Min Yin and
  • Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

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  • the 9-organoborane intermediate IM-16 probably through borane–olefin complexes. The suprafacial nature of the boron migration allowed the boron to be α-oriented in intermediate IM-16, which would give 10 with retention of the configuration after NaOH/H2O2 oxidation. The formation of a significant
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Published 18 Apr 2024

Advancements in hydrochlorination of alkenes

  • Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

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  • chloride metal halide complexes are −6 kJ mol−1 for SnCl4, −8 kJ mol−1 for BiCl3, −9 kJ mol−1 for ZnCl2, −15 kJ mol−1 for CdCl2, −16 kJ mol−1 for FeCl3, and −41 kJ mol−1 for AlCl3. d) Addition of chloride-containing salts (e.g., LiCl) accelerate the reaction. e) Traces of water can increase the rate of the
  • forms a dissociated hydrogen chloride aggregate in the form of complexes 103 or 105. An X-ray structure of complex 105 was reported and the reaction 104 → 105 is described in the report by Snyder, though not stoichiometric balanced. These complexes seem to play a pivotal role in the hydrochlorination
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Published 15 Apr 2024
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