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Search for "bicyclic" in Full Text gives 381 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Oxime radicals: generation, properties and application in organic synthesis

  • Igor B. Krylov,
  • Stanislav A. Paveliev,
  • Alexander S. Budnikov and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

Graphical Abstract
  • a constant HFC aN = 30 G and 32 G, corresponding to iminoxyl radicals 93. At higher temperature (+10 °C), only one signal was observed with aN = 19.75 G. This HFS value is characteristic of bicyclic nitroxyl radicals [123]. The authors suggested that the formed iminoxyl radical underwent cyclization
  • with the formation of alkyl radical 94. The latter attacked the nitrone moiety to form the bicyclic nitroxyl radical 95. When oxime 96 was oxidized with lead(IV) acetate, products 98 and 99 were observed. This result can be explained by the intramolecular attack of iminoxyl radical 97 on the phenyl π
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Published 05 Jun 2020

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

  • Stephanie G. E. Amos,
  • Marion Garreau,
  • Luca Buzzetti and
  • Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

Graphical Abstract
  • performs an SET oxidation of an cyclopropylaniline 36.1, leading to an N-centred radical cation after ring opening. The latter undergoes a [3 + 2] annulation with cyclopropenes 36.2, affording a bicyclic product 36.3. The key to the broad substrate tolerance relied on using 4DPAIPN (OD7), which is a mild
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Published 29 May 2020

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

  • Rasa Keruckiene,
  • Simona Vekteryte,
  • Ervinas Urbonas,
  • Matas Guzauskas,
  • Eigirdas Skuodis,
  • Dmytro Volyniuk and
  • Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

Graphical Abstract
  • is to employ both donor and acceptor moieties in a single molecular structure [1][2][3][4]. Quinazoline is a planar aromatic heterocyclic compound with the fused bicyclic structure consisting of benzene and pyrimidine rings. Quinazoline derivatives were investigated and used in medicinal applications
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Published 28 May 2020

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

  • Svetlana A. Kuznetsova,
  • Alexander S. Gak,
  • Yulia V. Nelyubina,
  • Vladimir A. Larionov,
  • Han Li,
  • Michael North,
  • Vladimir P. Zhereb,
  • Alexander F. Smol'yakov,
  • Artem O. Dmitrienko,
  • Michael G. Medvedev,
  • Igor S. Gerasimov,
  • Ashot S. Saghyan and
  • Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

Graphical Abstract
  • partitioning of the epoxide into the aqueous phase was necessary for reaction to occur. Cyclohexene oxide (5) is, however, a good substrate under the same reaction conditions (Table 2, entry 5), possibly due to the greater reactivity of its fused bicyclic ring system. The Diels–Alder reaction of methyl vinyl
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Published 26 May 2020

A simple and easy to perform synthetic route to functionalized thienyl bicyclo[3.2.1]octadienes

  • Dragana Vuk,
  • Irena Škorić,
  • Valentina Milašinović,
  • Krešimir Molčanov and
  • Željko Marinić

Beilstein J. Org. Chem. 2020, 16, 1092–1099, doi:10.3762/bjoc.16.96

Graphical Abstract
  • of two aromatic units (Scheme 1). The idea herein was to prepare thienyl analogues of the annulated furyl derivatives, as substrates suitable for biological testing and/or new precursors for further functionalization. Results and Discussion As starting precursors two bicyclic thiophene derivatives 1
  • -isomers 3–6 as representative examples. The detailed analysis of all new compounds' NMR spectra can be found in Supporting Information File 1. The 1H NMR spectra of the presented examples confirmed the conservation of the bicyclic core. Six proton pattern, characteristic for these bicyclic systems, were
  • bicyclic skeleton preserved. The UV spectrum of the aldol product 12, in comparison to the starting aldehyde 1, showed the expected red shift, under the prolonged conjugation in product 12 (Figure 10). Contrary to the results obtained on the styryl analogs 3–7, the preliminary irradiation experiments of
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Published 22 May 2020

Copper-catalysed alkylation of heterocyclic acceptors with organometallic reagents

  • Yafei Guo and
  • Syuzanna R. Harutyunyan

Beilstein J. Org. Chem. 2020, 16, 1006–1021, doi:10.3762/bjoc.16.90

Graphical Abstract
  • the synthesis of the corresponding products with good yield and enantiomeric purity (up to 83% yield and 97% ee). Furthermore, a large variety of vinylalanes was investigated, and the product 2l was further derivatised into a chiral bicyclic structure (5, Scheme 2A). In addition, simple vinyl
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Published 14 May 2020

Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules

  • Valerian Dragutan,
  • Ileana Dragutan,
  • Albert Demonceau and
  • Lionel Delaude

Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68

Graphical Abstract
  • the corresponding bicyclic dienic scaffolds. The subsequent hydroboration and aminohydroxylation carried out on these bicyclic dienes provided the AB subunit as a key intermediate component of manzamines A (16a) and E (16b, Scheme 19). Eventually, several highly elaborated transformations of the AB
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Published 16 Apr 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
  • the details of the mechanism for the hydrofunctionalization of internal alkenes and vinyl arenes (Scheme 55) [100]. Unlike acyclic alkenes, Tortosa et al. utilized cyclobutenes as well as bicyclic cyclobutenes as educts using (R)-DM-Segphos for Cu-catalyzed enantioselective borylation, affording
  • on the interest in Cu-catalyzed aminoboration reactions of a variety of alkenes, such as bicyclic alkenes [124], Miura et al. subsequently described the preparation of β-borylalkylamines 401–404 from unactivated terminal alkenes 307 (Scheme 64). Using a mixed diborane reagent, such as pinB–Bdan
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Published 15 Apr 2020

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

  • Zeguo Fang,
  • Nawaf Al-Maharik,
  • Peer Kirsch,
  • Matthias Bremer,
  • Alexandra M. Z. Slawin and
  • David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

Graphical Abstract
  • CF2-containing cyclopropanes 11a and 11b became targets to assess the impact of a configurationally rigid bicyclic motif. It is relatively obvious that for each of these isomers the CF2 dipole in each cyclopropane is orientated either along the molecular axis (for 11a) or perpendicular to the
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Published 14 Apr 2020

Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin

  • Anna R. Bockman and
  • Jeffrey M. Pruet

Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46

Graphical Abstract
  • yields often >80%. Keywords: amidation; DBU; folate; pterin; Introduction Pteridines are a class of fused bicyclic heterocycles with significant biological relevance. The 2-amino-4-pteridinone core, simply referred to as “pterin”, is present in various biological cofactors like folates, biopterin, and
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Published 26 Mar 2020

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

  • Mingbing Zhong,
  • Xavier Pannecoucke,
  • Philippe Jubault and
  • Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

Graphical Abstract
  • the best copper-based photocatalyst, Collins and co-workers reported the synthesis of a bicyclic lactone by a PCET reaction manifold (Scheme 32) [39]. Using their methodology, the authors discovered the [Cu(I)(quinitri)(xantphos)]BF4 catalyst as the best one, which afford the cis-lactone in 79
  • ester derivatives. δ-Functionalization of alcohols using [Cu(I)(dmp)(xantphos)]BF4. Photocatalytic synthesis of [5]helicene and phenanthrene. Oxidative carbazole synthesis using in situ-formed [Cu(I)(dmp)(xantphos)]BF4. Copper-photocatalyzed functionalization of N-aryl tetrahydroisoquinolines. Bicyclic
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Published 23 Mar 2020

Architecture and synthesis of P,N-heterocyclic phosphine ligands

  • Wisdom A. Munzeiwa,
  • Bernard Omondi and
  • Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

Graphical Abstract
  • with aminosilanes which produces trimethylchlorosilane as a byproduct which can be distilled off easily [102]. Bicyclic guanidine frameworks present an opportunity to form inflexible ligands that are inclined to exhibit a κ2-P,N-bonding mode in metal complexes. Dyer et al. [103] prepared cycloguanidine
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Published 12 Mar 2020

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

  • Katarzyna Włodarczyk,
  • Piotr Borowski and
  • Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

Graphical Abstract
  • . The nature of this difference is currently a subject of further research in our laboratory. Nevertheless, the above results opened a new pathway for the synthesis of bicyclic organophosphorus compounds possessing a chirality center at phosphorus. Moreover, the formation of the bicyclic compounds
  • stereoselectivity. It was found that the P-stereogenic β-/γ-mercaptoalkylphosphine oxides underwent intramolecular cyclization to the corresponding bicyclic phosphine oxides with high stereoselectivity and high yield under mild reaction conditions. 1H NMR spectra of compounds 12 and 29. 13C NMR spectra of compounds
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Published 21 Jan 2020

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering

  • Eric J. N. Helfrich,
  • Geng-Min Lin,
  • Christopher A. Voigt and
  • Jon Clardy

Beilstein J. Org. Chem. 2019, 15, 2889–2906, doi:10.3762/bjoc.15.283

Graphical Abstract
  • cationic species. For instance, remodeling the hydrophobic pocket of the active site by single-point mutation, epi-isozizaene (33) synthase was engineered to produce various linear, monocyclic, bicyclic, and tricyclic terpene skeletons (Figure 9b) [119][120][121]. Another prominent example is cyclooctat-9
  • , simply by rationally mutating the active-site residues. The majority of bacterial type II diterpene TCs produce bicyclic labdane, halimadane, or clerodane skeletons with different stereochemistry, levels of unsaturation, and hydroxylation patterns [124], which undergo further conversion with their
  • (Figure 10b) [131]. Similarly, by mutating two residues of P450BM3 that control the shape of the substrate binding cavity, the enzyme was engineered to accept different linear, monocyclic, and bicyclic terpenes [132]. The alteration of the native sequences uses either method or the combination of the two
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Published 29 Nov 2019

Synthesis of aryl-substituted thieno[3,2-b]thiophene derivatives and their use for N,S-heterotetracene construction

  • Nadezhda S. Demina,
  • Nikita A. Kazin,
  • Nikolay A. Rasputin,
  • Roman A. Irgashev and
  • Gennady L. Rusinov

Beilstein J. Org. Chem. 2019, 15, 2678–2683, doi:10.3762/bjoc.15.261

Graphical Abstract
  • light-harvesting dyes for dye-sensitized solar cells [1], electron-donating materials for bulk heterojunction solar cells [2][3][4], and p-type semiconductors for organic field-effect transistors [5][6][7]. Within the same context of organic semiconductor development, the bicyclic TT subunit has been
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Published 12 Nov 2019

Unexpected one-pot formation of the 1H-6a,8a-epiminotricyclopenta[a,c,e][8]annulene system from cyclopentanone, ammonia and dimethyl fumarate. Synthesis of highly strained polycyclic nitroxide and EPR study

  • Sergey A. Dobrynin,
  • Igor A. Kirilyuk,
  • Yuri V. Gatilov,
  • Andrey A. Kuzhelev,
  • Olesya A. Krumkacheva,
  • Matvey V. Fedin,
  • Michael K. Bowman and
  • Elena G. Bagryanskaya

Beilstein J. Org. Chem. 2019, 15, 2664–2670, doi:10.3762/bjoc.15.259

Graphical Abstract
  • in hydride abstraction with the formation of carbocation 9 and subsequent cyclization to the bicyclic alkoxyamine 10. The resulting isoxazolidine ring is then opened with m-CPBA in the usual way, retaining the configuration of the asymmetric center at 3aC-OH [13] (Scheme 4). The steric strain in
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Published 07 Nov 2019

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

  • Anna Kmieciak and
  • Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

Graphical Abstract
  • rearrangement reaction may be the rigid bicyclic structure of the substrate and steric hindrance on one side of the molecule caused by the gem-dimethyl bridge. Conclusion Regioisomeric exocyclic allylic alcohols were synthesized from natural α-pinene. (1R,2R,4S,5R)-3-Methyleneneoisoverbanol and (1R,2R,3R,5R)-4
  • the less hindered side of the molecule to produce γ-hydroxyphosphine oxide derivatives. It was also shown that phosphine oxide can be reduced to phosphine without affecting the bicyclic pinane structure. The synthesis of diastereomeric endocyclic allylic alcohols from (−)-β-pinene was also carried out
  • . Unfortunately, due to the probably too rigid bicyclic structure of the diphenylphosphinites, they did not undergo the sigmatropic rearrangement to the corresponding phosphine oxides. Further research and application of the obtained ligands are in progress. Experimental Diphenyl(((1R,2R,5S)-δ-pinen-3-yl)methyl
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Published 22 Oct 2019

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

  • Ronja Driller,
  • Daniel Garbe,
  • Norbert Mehlmer,
  • Monika Fuchs,
  • Keren Raz,
  • Dan Thomas Major,
  • Thomas Brück and
  • Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

Graphical Abstract
  • diterpenes synthesized by the respective synthase mutants are missing the bond between C2 and C6 compared to cyclooctatin (5). Hence, they are comprising a 5,11-fused bicyclic skeleton. In contrast, cembranoids are monocyclic compounds consisting of a 14 membered ring structure. Common to all compounds
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Published 02 Oct 2019

Isolation of fungi using the diffusion chamber device FIND technology

  • Benjamin Libor,
  • Henrik Harms,
  • Stefan Kehraus,
  • Ekaterina Egereva,
  • Max Crüsemann and
  • Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

Graphical Abstract
  • ), 122.1 (C-4), 143.0 (C-10) and 129.5 (C-11) evidenced two carbon–carbon double bonds. Together with a carbonyl carbon at δC 206.6 and a carboxylic carbon at δC 177.8, the two remaining DOU were accounted to a bicyclic ring system. After assigning the proton resonances to the 13C resonances of directly
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Published 19 Sep 2019

Genome mining in Trichoderma viride J1-030: discovery and identification of novel sesquiterpene synthase and its products

  • Xiang Sun,
  • You-Sheng Cai,
  • Yujie Yuan,
  • Guangkai Bian,
  • Ziling Ye,
  • Zixin Deng and
  • Tiangang Liu

Beilstein J. Org. Chem. 2019, 15, 2052–2058, doi:10.3762/bjoc.15.202

Graphical Abstract
  • by genome mining and determined the structure of its corresponding products. One new 5/6 bicyclic sesquiterpene and its esterified derivative were characterised by GC–MS and 1D and 2D NMR spectroscopy. To the best of our knowledge, this is the first well-identified sesquiterpene synthase from T
  • characterised by GC–MS and 1D and 2D NMR, revealing a 5/6 bicyclic sesquiterpene and its C-11 esterified structure. Based on a literature search, to our knowledge, this is the first report of the characterisation of a sesquiterpene synthase in T. viride. In addition, this study demonstrates the effectiveness of
  • 5/6 bicyclic sesquiterpene with the molecular formula C15H26O (Figure 1). Interestingly, compound 1 contained a quaternary carbon with two methyl groups, which is uncommon for the cyclization mechanism of sesquiterpenoids and needs further investigation. Compound 2 was purified as a white powder. 1H
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Published 28 Aug 2019

A review of the total syntheses of triptolide

  • Xiang Zhang,
  • Zaozao Xiao and
  • Hongtao Xu

Beilstein J. Org. Chem. 2019, 15, 1984–1995, doi:10.3762/bjoc.15.194

Graphical Abstract
  • form the A- and D-ring. The second one involves the reaction of the bicyclic intermediate 13 and 2-isopropyl-1,4-benzoquinone (14) to form the B- and C-ring. Finally, a regio- and stereoselective reduction, methylation and dehydration procedure and a selenylation, oxidation and elimination procedure
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Published 22 Aug 2019
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  • -copaene, β-copaene, α-cubebene, β-cubebene and the bicyclic δ-cadinene were biosynthesized via (S)-(−)-germacrene D rather than via (R)-(+)-germacrene D as intermediate. Keywords: biosynthesis; deuterium labeling; germacrene; HS-SPME; terpenes; TOF–MS; Introduction The aroma profile of grape berries at
  • the time of physiological ripening is very complex and significantly influenced by potent flavoring substances of isoprenoid origin like mono- and sesquiterpenes [1][2]. Sesquiterpenes form a structurally diverse subgroup of terpenes consisting of three isoprene units [3]. Since the bicyclic
  • photoinduced [2 + 2]-cycloaddition is very unlikely. The biosynthesis of β-bourbonene can be performed by cationic cyclization, as shown in Scheme 4. A total of 5 bicyclic, aromatic sesquiterpene hydrocarbons (21–25) with a cadinane skeleton were found in exocarp of the grape variety Lemberger, whose identity
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Published 14 Aug 2019

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

  • Iwona E. Głowacka,
  • Aleksandra Trocha,
  • Andrzej E. Wróblewski and
  • Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

Graphical Abstract
  • can serve as the starting material to a variety of orthogonally protected derivatives of 2,3-diaminopropanoic acid. The bicyclic amino acid (S)-127 is a major metabolite of isazofos in corn grain and for toxicological studies both enantiomers were required [17]. To this end the aziridine ester (2S,1′R
  • )-5a was reacted with 3-bromo-5-methoxy-1H-1,2,4-triazole (128) to give N-protected bicyclic amino ester 129 which was next converted into (S)-(+)-127 in two standard steps (Scheme 33) [17]. Its enantiomer was prepared from (2R,1′S)-5a. Lacosamide ((R)-130) is a derivative of ᴅ-serine and has found
  • transition state was involved. Acid-induced aziridine ring openings and subsequent conjugate additions to the α,β-unsaturated lactone led to the formation of cis-fused [5,5']bicyclic compounds 186a or 186b. Reduction of the lactone moiety in 186a and subsequent deprotection gave (2S,3R,4S,5R)-184. In order
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Published 23 Jul 2019

Synthesis and biological evaluation of truncated derivatives of abyssomicin C as antibacterial agents

  • Leticia Monjas,
  • Peter Fodran,
  • Johanna Kollback,
  • Carlo Cassani,
  • Thomas Olsson,
  • Maja Genheden,
  • D. G. Joakim Larsson and
  • Carl-Johan Wallentin

Beilstein J. Org. Chem. 2019, 15, 1468–1474, doi:10.3762/bjoc.15.147

Graphical Abstract
  • structure–activity relationship studies towards novel antibiotics targeting 4-amino-4-deoxychorismate (ADC) synthase. Specifically, it is demonstrated that the synthetically challenging bicyclic motif is essential for activity towards methicillin-resistant Staphylococcus aureus (MRSA). Keywords
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Published 02 Jul 2019

Switchable selectivity in Pd-catalyzed [3 + 2] annulations of γ-oxy-2-cycloalkenones with 3-oxoglutarates: C–C/C–C vs C–C/O–C bond formation

  • Yang Liu,
  • Julie Oble and
  • Giovanni Poli

Beilstein J. Org. Chem. 2019, 15, 1107–1115, doi:10.3762/bjoc.15.107

Graphical Abstract
  • combination may allow direct access to either fused bicyclic cyclopentanic (pentalene-, indene-, or azulene-type) structures via a γ-C-allylation/β-C-1,4 addition process, or annulated furan-based motifs through a γ-C-allylation/β-O-1,4 addition process, both motifs being incorporated into biologically
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Published 16 May 2019
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