Search results

Search for "quinone" in Full Text gives 130 result(s) in Beilstein Journal of Organic Chemistry.

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

  • Ramazan Koçak and
  • Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

Graphical Abstract
  • inverse electron-demand Diels–Alder cycloaddition reactions between a dibenzosuberenone and tetrazines that bear various substituents. The pyridazines were synthesized in high yields by oxidation of dihydropyridazine-appended dibenzosuberenones with PIFA or NO. p-Quinone derivatives of pyridazines were
  • also obtained by H-shift isomerization following the inverse electron-demand Diels–Alder reaction of tetrazines with p-quinone dibenzosuberenone. Then these pyridazines were converted to the corresponding pyrroles by reductive treatment with zinc. It was observed that all the dihydropyridazines
  • obtained gave absorbance and emission at long wavelengths. Keywords: dibenzosuberenone; inverse electron-demand Diels–Alder cycloaddition reactions; p-quinone methide; polycyclic π-conjugated dihydropyridazines; pyridazines; pyrroles; Inroduction Dibenzosuberone and dibenzosuberenone derivatives are
PDF
Album
Supp Info
Full Research Paper
Published 15 Mar 2021

[2 + 1] Cycloaddition reactions of fullerene C60 based on diazo compounds

  • Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

Graphical Abstract
  • the synthesis of various spiromethanofullerenes. For example, spiro derivatives 73–75 were obtained in one of the first works on this subject (Figure 7). The authors obtained quinone-derived [6,6]-closed spiromethanofullerenes 76–78 by reactions of C60 with the corresponding diazo compounds upon
  • ]. Subsequently, the scope of quinone-substituted methanofullerenes was expanded by derivatives 82 and 83, and the scope of indanedione-substituted derivatives by compound 84. All of them were synthesized under conditions similar to those indicated in Scheme 24 (Figure 8) [112]. Synthesis of methanofullerenes
  • . Structures of complexes 63–65. Structures of spiromethanofullerenes 73–75. Quinone-substituted spiromethanofullerenes 82–84. Structures of 4-C61-phenylorganofullerenes 159 and 160. Structures of methanofullerenes containing aromatic polycyclic systems. 4,4-Diphenylfullerene derivatives 31, 32, 167, and 168
PDF
Review
Published 05 Mar 2021

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

  • Sergey V. Norkov,
  • Anton V. Cherkasov,
  • Andrey S. Shavyrin,
  • Maxim V. Arsenyev,
  • Viacheslav A. Kuropatov and
  • Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

Graphical Abstract
  • activity. An effective method for the synthesis of sterically hindered o-quinones containing 1,3-diketonate, dinitrile and p-quinone-methide functional groups at the periphery of the ligand has been developed. The novel compounds have rigid and conjugated structures and exhibit properties typical of o
  • -quinones. A study of their monoreduced semiquinone derivatives reveal that the spin density is delocalized across the whole molecule, including peripheral fragments. The first stable o-quinone derivative bearing an annulated thiete heterocycle has been isolated and characterized. Keywords: dioxolene
  • ligand; 1,3-dithiole; ditopic ligand; o-quinone; thiete; Introduction There are a number of methods which may be used for the synthesis of new o-quinones in order to vary their redox properties and coordination abilities. The key features of o-quinones are redox activity as well as chelating
PDF
Album
Supp Info
Full Research Paper
Published 27 Jan 2021

Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

  • Xinru Sheng,
  • Errui Li and
  • Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

Graphical Abstract
  • 450001, P. R. China 10.3762/bjoc.16.245 Abstract We report novel pseudorotaxanes based on the complexation between pillar[4]arene[1]quinone and 1,10-dibromodecane. The complexation is found to have a 1:1 host–guest complexation stoichiometry in chloroform but a 2:1 host–guest complexation stoichiometry
  • in the solid state. From single crystal X-ray diffraction, the linear guest molecules thread into cyclic pillar[4]arene[1]quinone host molecules in the solid state, stabilized by CH∙∙∙π interactions and hydrogen bonds. The bromine atoms at the periphery of the guest molecule provide convenience for
  • new pseudorotaxanes based on the pillar[4]arene[1]quinone H and 1,10-dibromodecane (G, Scheme 1). The pillar[4]arene[1]quinone H, which is composed of four 1,4-diethoxybenzene subunits and one benzoquinone subunit, was prepared by partial oxidation of perethylated pillar[5]arene according to previous
PDF
Album
Supp Info
Full Research Paper
Published 02 Dec 2020

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

  • Shakeel Alvi and
  • Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

Graphical Abstract
  • sumanene provided the covalent adduct 171 with Cl atoms attached onto the Te atoms, confirmed by an X-ray analysis (Scheme 44). Having the quinone derivatives 166 and 167 in hands, they were next subjected to the condensation reaction with a variety of aryl-1,2-diamines 168 in the presence of AcOH to
PDF
Album
Review
Published 09 Sep 2020

Synthesis of 6,13-difluoropentacene

  • Matthias W. Tripp and
  • Ulrich Koert

Beilstein J. Org. Chem. 2020, 16, 2136–2140, doi:10.3762/bjoc.16.181

Graphical Abstract
  • subsequent reduction step using NaBH4 to diol 13 was performed without further purification of the quinone. The low yield for the formation of 13 seems to be an intrinsic instability of its ortho-fluorobenzylic alcohol moiety. Moreover, the compound quantitatively decomposes to 6,13-pentacenequinone 15 in
PDF
Album
Supp Info
Full Research Paper
Published 02 Sep 2020

The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization

  • Sharna-kay Daley and
  • Nadale Downer-Riley

Beilstein J. Org. Chem. 2020, 16, 2026–2031, doi:10.3762/bjoc.16.169

Graphical Abstract
  • ) [17] and violet-quinone (3) [18] (Figure 1). Similar to those natural products, the biomimetic synthesis of balsaminone A (4) and ellagic acid (5) can be attained using oxidative dimerization reactions, based on their proposed biosynthesis (Scheme 1 and Scheme 2) [19][20]. These pathways, which start
  • which undergoes reduction to the dihydroxynaphthalene 8. This is then dimerized by the copper-rich enzyme to quinone arenol 9, which, following intramolecular cyclization, affords balsaminone A (4, Scheme 1). Similarly, the biosynthetic precursor of ellagic acid (5), gallic acid (10), undergoes
  • 16 in 29, 34, and 19% yields, respectively (Table 1). As anticipated, the reaction of naphthalene 17 with CAN under aqueous conditions resulted in preferential oxidative demethylation to give quinone 7, as opposed to oxidative dimerization. The elimination of water from the reaction posed a few
PDF
Album
Supp Info
Full Research Paper
Published 18 Aug 2020

NHC-catalyzed enantioselective synthesis of β-trifluoromethyl-β-hydroxyamides

  • Alyn T. Davies,
  • Mark D. Greenhalgh,
  • Alexandra M. Z. Slawin and
  • Andrew D. Smith

Beilstein J. Org. Chem. 2020, 16, 1572–1578, doi:10.3762/bjoc.16.129

Graphical Abstract
  • enantioselectivity but requiring superstoichiometric quantities of quinone as an oxidant (Figure 2B) [47]. In our previous work, we have developed α-aroyloxyaldehydes as reactive, bench-stable precursors of azolium enolates [48][49][50][51][52][53], which can be synthesized in a single step from the desired aldehyde
PDF
Album
Supp Info
Letter
Published 30 Jun 2020

Activated carbon as catalyst support: precursors, preparation, modification and characterization

  • Melanie Iwanow,
  • Tobias Gärtner,
  • Volker Sieber and
  • Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

Graphical Abstract
  • –OCO), phenolic groups (R–OH) and carbonyl or quinone groups (R=O). Differentiation is possible by titration with different basic solutions NaHCO3, Na2CO3, NaOH, NaOC2H5, respectively. Titration of the samples with hydrochloric acid determines the basic properties on activated carbon surface in form of
  • gases were determined by mass spectrometry. In general, each type of surface group decomposes to a defined product such as CO2 from carboxylic acid or lactones and CO from carbonyl, hydroxide, phenol, ether or quinone groups and thus, information on the amounts of oxygen-containing surface groups are
PDF
Album
Review
Published 02 Jun 2020

Recent advances in Cu-catalyzed C(sp3)–Si and C(sp3)–B bond formation

  • Balaram S. Takale,
  • Ruchita R. Thakore,
  • Elham Etemadi-Davan and
  • Bruce H. Lipshutz

Beilstein J. Org. Chem. 2020, 16, 691–737, doi:10.3762/bjoc.16.67

Graphical Abstract
  • an enol system, as in the case of unsaturated ketones which is not easy to isolate, could be modified in such way that the resultant intermediate is highly stable. For example, Tortosa [65] showed that this type of catalytic system could be applied to the quinone methide system 162, which is
  • cyclobutyl boronates in high yields and with excellent stereocontrol [101]. This work followed on the heels of earlier studies on the borylation of 2,6-disubstituted p-quinone methides en route to enantioenriched mono- and dibenzylic boronates [102]. An efficient regio-divergent method starting from a single
PDF
Album
Review
Published 15 Apr 2020

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

  • Xiaodong Zhang,
  • Jun Xie,
  • Zhiling Xu,
  • Zhu Tao and
  • Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

Graphical Abstract
  • , baicalein contains three phenolic hydroxy groups, which are easily oxidized to the quinone derivative and appear green, therefore, it has limited use in pharmaceuticals on account of its poor aqueous solubility and stability [31]. The cucurbit[n]urils (Q[n]s n = 5–8, 10, …) are macrocyclic hosts with a
  • study BALE has three phenolic hydroxy groups, which are easily oxidized to a quinone-type structure. The time-resolved UV–vis absorption spectra of BALE showed that the stability of BALE in water was poor in the absence of Q[8], whereas the stability of BALE was greatly improved in the presence of Q[8
PDF
Album
Supp Info
Full Research Paper
Published 10 Jan 2020

An overview of the cycloaddition chemistry of fulvenes and emerging applications

  • Ellen Swan,
  • Kirsten Platts and
  • Anton Blencowe

Beilstein J. Org. Chem. 2019, 15, 2113–2132, doi:10.3762/bjoc.15.209

Graphical Abstract
  • reaction, causing the formation of complex products. Examples of dienes that have previously been used include cyclic diketones (o-benzoquinones) (Scheme 15, reaction pathways (i)) [60][89][156][157][158][160][161][162][163][164][165][211][215][226], o-quinone methides [87], o-xylylenes [125][153
PDF
Album
Review
Published 06 Sep 2019

Mechanochemical Friedel–Crafts acylations

  • Mateja Đud,
  • Anamarija Briš,
  • Iva Jušinski,
  • Davor Gracin and
  • Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

Graphical Abstract
  • naphthalene were less reactive under the same ball milling conditions and reactions stopped at the stage of formation of product 3 and 15. One-step preparation of quinone 30 [39], was achieved by melting reactants at 140 °C for 10 min. Under these conditions, a mixture of adducts 3 and 30 (1.5:1 ratio) was
  • obtained. The product ratio was established by 1H NMR analysis of the characteristic H-10 proton signal of product 3 (peak resonance doublet at δ 9.2 ppm), which is shifted towards lower magnetic field in quinone 30 (δ 10.0 ppm), and concurrent appearance of singlet for H-3 at δ 9.1 ppm. These experiments
PDF
Album
Supp Info
Full Research Paper
Published 17 Jun 2019

Heck- and Suzuki-coupling approaches to novel hydroquinone inhibitors of calcium ATPase

  • Robert J. Kempton,
  • Taylor A. Kidd-Kautz,
  • Soizic Laurenceau and
  • Stefan Paula

Beilstein J. Org. Chem. 2019, 15, 971–975, doi:10.3762/bjoc.15.94

Graphical Abstract
  • -step sequence of oxidation employing ammonium cerium(IV) nitrate (CAN) [20] to afford the corresponding quinone (not shown), followed by reduction with sodium hydrosulfite [21]. With the nitrile in hand, we next attempted to reduce that functional group to an amine to which a leucine moiety could be
  • Na2S2O4 or H2/Pd). What finally proved effective was the two step sequence of oxidation of 12a with CAN followed by treatment of the resulting quinone 13 with sodium borohydride in dry methanol – a sequence that gave 14 (which upon standing readily re-oxidizes back to 13) in 34% overall yield from 12a. A
PDF
Album
Supp Info
Full Research Paper
Published 24 Apr 2019

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step

  • Pierre-Antoine Nocquet,
  • Aurélie Macé,
  • Frédéric Legros,
  • Jacques Lebreton,
  • Gilles Dujardin,
  • Sylvain Collet,
  • Arnaud Martel,
  • Bertrand Carboni and
  • François Carreaux

Beilstein J. Org. Chem. 2018, 14, 2949–2955, doi:10.3762/bjoc.14.274

Graphical Abstract
  • was developed based on a Stille coupling to install the C-linked sugar residue [3]. Moreover, the addition of lithiated glycals to quinone derivatives followed by a rearrangement was also studied for the synthesis of kidamycin according to a “reverse polarity” strategy [4][5]. Considering that the
PDF
Album
Supp Info
Full Research Paper
Published 29 Nov 2018

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

  • Piotr Pomarański,
  • Piotr Roszkowski,
  • Jan K. Maurin,
  • Armand Budzianowski and
  • Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

Graphical Abstract
  • auxiliaries. Therefore, the atropselective synthesis is an important synthetic approach pursued by many research groups [22][23][24][25][26]. In 2015 the first phosphoric acid-catalysed asymmetric reactions of 2-naphthols with quinone analogues were described, allowing an access to a class of sterically
PDF
Album
Supp Info
Full Research Paper
Published 11 Sep 2018

The enzymes of microbial nicotine metabolism

  • Paul F. Fitzpatrick

Beilstein J. Org. Chem. 2018, 14, 2295–2307, doi:10.3762/bjoc.14.204

Graphical Abstract
  • oxidative demethylation of 4-(methoxymethyl)phenols via a quinone methide intermediate [28][29]. Based on this precedent and the assumption that DHNO oxidizes the C2–C3 bond, Koetter and Schultz [27] proposed the mechanism shown in Scheme 5 for DHNO. However, members of the p-cresol methylhydroxylase
  • more consistent with the simple mechanism of Scheme 4 (Fitzpatrick et al., manuscript in preparation). The proposed quinone methide is not detected during stopped-flow analyses of either the wild-type enzyme or the E352Q variant, (R)-6-chloronicotine and (R)-nicotine, which would not form the quinone
PDF
Album
Review
Published 31 Aug 2018

First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones

  • Grzegorz Mlostoń,
  • Katarzyna Urbaniak,
  • Paweł Urbaniak,
  • Anna Marko,
  • Anthony Linden and
  • Heinz Heimgartner

Beilstein J. Org. Chem. 2018, 14, 1834–1839, doi:10.3762/bjoc.14.156

Graphical Abstract
  • cycloadduct was isolated in 37% yield. Keywords: hetero-Diels–Alder reactions; quinone dyes; quinones; sulfur heterocycles; thiochalcones; Introduction Hetero-Diels–Alder reactions are considered to be a powerful methodology widely explored for the synthesis of six-membered heterocycles [1][2] with numerous
  • all other initially formed cycloadducts, further oxidative conversion to the quinone structure was not possible in this case. Conclusion The present study demonstrates that 1,4-quinones are prone dienophiles in reactions with aryl/hetarylthiochalcones. These thia-Diels–Alder reactions led to a new
  • class of 4H-thiopyran derivatives. The presence of a quinone system is an important structural aspect of this class as it is common in many naturally occurring compounds, e.g., dyes such as alizarin, carminic acid, and isoprenoid dyes, as well as drugs such as doxorubicin. In addition, the presence of
PDF
Album
Supp Info
Full Research Paper
Published 19 Jul 2018

Anomeric modification of carbohydrates using the Mitsunobu reaction

  • Julia Hain,
  • Patrick Rollin,
  • Werner Klaffke and
  • Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1619–1636, doi:10.3762/bjoc.14.138

Graphical Abstract
  • anomeric aci-nitroester 131 is formed, which is converted into the corresponding gluconolactone 133 under elimination of a quinone monoxime 132 (Scheme 28). Conclusion In this account, 15 years after Professor Mitsunobu has passed away, we have surveyed the literature on the Mitsunobu reaction for anomeric
PDF
Album
Review
Published 29 Jun 2018

One hundred years of benzotropone chemistry

  • Arif Dastan,
  • Haydar Kilic and
  • Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

Graphical Abstract
  • -benzotropone (12) was also performed (Scheme 36). This condensation followed by incipient oxidation gave the quinone 223 (15%), the bridged bicyclic product 224 (7%), and 225 (28%) [152]. 4. Chemistry of 3,4-benzotropone (13) 4.1. Generation, characterization, and reaction 3,4-Benzotropone (13) is of
  • reactions were carried out at various quinone/BF3.OEt2/CH2N2 molar ratios in a different solvent under an atmosphere of nitrogen and with cooling in an ice bath and 3,4-benzotropolonoboron difluoride 281 was obtained in 2–25.5% yield. The hydrolysis of chelate compound 281 was performed with dilute sulfuric
PDF
Album
Review
Published 23 May 2018

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

  • Eirinaios I. Vrettos,
  • Gábor Mező and
  • Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

Graphical Abstract
  • . Furthermore, they stabilize the topoisomerase II DNA complex preventing the transcription. They may also increase quinone type free radical production, however, this plays a role rather in their cytotoxic side effects. Daunorubicin is mainly used in the treatment of leukemia [95] while doxorubicin in the cure
PDF
Album
Review
Published 26 Apr 2018

Nanoreactors for green catalysis

  • M. Teresa De Martino,
  • Loai K. E. A. Abdelmohsen,
  • Floris P. J. T. Rutjes and
  • Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

Graphical Abstract
  • of glucose oxidase (GOx) to convert glucose into D-glucono-δ-lactone and hydrogen peroxide was the first step of the reaction (Scheme 3A); subsequently, myoglobin (Myo) employed the hydrogen peroxide produced to oxidize guaiacol to quinone and water (Scheme 3B). When the pH was below 7, the
PDF
Album
Review
Published 29 Mar 2018

Mannich base-connected syntheses mediated by ortho-quinone methides

  • Petra Barta,
  • Ferenc Fülöp and
  • István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

Graphical Abstract
  • Mannich reactions where the process involves an ortho-quinone methide (o-QM) intermediate. The reactions are classified on the basis of the o-QM source followed by the reactant, e.g., the dienophile partner in cycloaddition reactions (C=C or C=N dienophiles) or by the formation of multicomponent Mannich
  • adducts. Due to the important pharmacological activities of these reactive o-QM intermediates, special attention is paid to the biological activity of these compounds. Keywords: aminophenols; [4 + 2] cycloaddition; dienophile; Mannich reaction; ortho-quinone methide; Review Introduction The Mannich
  • and the aldehyde yields a Schiff base and then the latter reacts with 2-naphthol in the second nucleophilic addition step. The other theory assumes the formation of an ortho-quinone methide (o-QM) intermediate by the reaction of 2-naphthol and benzaldehyde. Re-aromatization, the driving force of the
PDF
Album
Review
Published 06 Mar 2018

Quinone-catalyzed oxidative deformylation: synthesis of imines from amino alcohols

  • Xinyun Liu,
  • Johnny H. Phan,
  • Benjamin J. Haugeberg,
  • Shrikant S. Londhe and
  • Michael D. Clift

Beilstein J. Org. Chem. 2017, 13, 2895–2901, doi:10.3762/bjoc.13.282

Graphical Abstract
  • Xinyun Liu Johnny H. Phan Benjamin J. Haugeberg Shrikant S. Londhe Michael D. Clift Department of Chemistry, The University of Kansas, 2010 Malott Hall, 1251 Wescoe Hall Drive, Lawrence, KS, 66045, United States 10.3762/bjoc.13.282 Abstract A new method for imine synthesis by way of quinone
  • synthetic versatility of quinone-catalyzed oxidative C–C bond cleavage. Keywords: catalysis; deformylation; organic synthesis; organocatalysis; Introduction Imines are extremely versatile intermediates in organic chemistry [1][2][3]. Consequently, many synthetic methods have been developed for the
  • high-value imine products under catalytic conditions has the potential to be broadly useful. Herein, we report a new method that utilizes quinone catalysis to enable the synthesis of imines via oxidative deformylation of amino alcohols. Our group has recently reported the quinone-catalyzed
PDF
Album
Supp Info
Letter
Published 28 Dec 2017

CF3SO2X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF3SO2Na

  • Hélène Guyon,
  • Hélène Chachignon and
  • Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

Graphical Abstract
  • conditions tolerated a broad range of functional groups and the yields ranged from 31 to 68% (Scheme 50). During the process, the quinone was converted into hydroquinone and a regeneration process was established by passing through a cartridge of MnO2. A mechanism for this transformation was proposed as a
PDF
Album
Full Research Paper
Published 19 Dec 2017
Other Beilstein-Institut Open Science Activities