Search results

Search for "bicyclic" in Full Text gives 386 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Base-promoted isomerization of CF3-containing allylic alcohols to the corresponding saturated ketones under metal-free conditions

  • Yoko Hamada,
  • Tomoko Kawasaki-Takasuka and
  • Takashi Yamazaki

Beilstein J. Org. Chem. 2017, 13, 1507–1512, doi:10.3762/bjoc.13.149

Graphical Abstract
  • proton shift was published by using the bicyclic guanidine-type base, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), as a catalyst. In spite of these two preceding studies, we have also succeeded in attaining a similar level of chemical yields as well as stereoselectivity to the latter process by using far
PDF
Album
Supp Info
Full Research Paper
Published 01 Aug 2017

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

  • M. Fernanda N. N. Carvalho,
  • Rudolf Herrmann and
  • Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

Graphical Abstract
  • example for such a “chiral pool” starting material is camphor. Both its substituents and its bicyclic skeleton can easily be modified and adapted to the purpose at hand, e.g., natural product synthesis [5]. The Wagner–Meerwein and Nametkin-type rearrangements are the most common reaction patterns [6] and
  • (Scheme 1) [20]. A hydroxy group neighbouring an alkynyl substituent, under treatment with acids, normally leads to Rupe and Meyer–Schuster rearrangements, forming unsaturated carbonyl compounds. This was indeed observed in camphor-derived bicyclic alcohols containing a single ethinyl group [21][22
  • carbocyclic five-membered ring to the 2,3-position of the bicyclic camphor-derived moiety (Scheme 2a) [20]. Reactions of 4a with halogens (e.g., bromine) or acids were even more puzzling. In addition to the annulation, an unprecedented formation of a ketone accompanied by the reduction of sulphur took place
PDF
Album
Supp Info
Full Research Paper
Published 26 Jun 2017

A strategic approach to [6,6]-bicyclic lactones: application towards the CD fragment of DHβE

  • Tue Heesgaard Jepsen,
  • Emil Glibstrup,
  • François Crestey,
  • Anders A. Jensen and
  • Jesper Langgaard Kristensen

Beilstein J. Org. Chem. 2017, 13, 988–994, doi:10.3762/bjoc.13.98

Graphical Abstract
  • effective synthetic protocol to access [6,6]-bicyclic lactone moieties through a regio- and stereoselective intramolecular Mizoroki–Heck cross-coupling reaction followed by a 6π-electrocyclization. This method enabled the first synthesis of the elusive CD fragment of the Erythrina alkaloid DHβE. Preliminary
  • pharmacological evaluations support the notion that the key pharmacophores of DHβE are located in the A and B rings. Keywords: DhβE; Mizoroki–Heck cross-coupling reaction; 6π-electrocyclization; [6,6]-bicyclic lactone; vinyl halide; Introduction The neuronal nicotinic acetylcholine receptors (nAChRs) have been
  • for aromatic erythrinanes [2] whereas only four total syntheses of lactonic erythrinanes have been published so far [13][14][15][16]. Hence, for the DHβE-based CD fragments, we faced a significantly more challenging synthesis due to the complex nature of the [6,6]-bicyclic lactone moiety for which
PDF
Album
Supp Info
Full Research Paper
Published 22 May 2017

Use of costic acid, a natural extract from Dittrichia viscosa, for the control of Varroa destructor, a parasite of the European honey bee

  • Kalliopi Sofou,
  • Demosthenis Isaakidis,
  • Apostolos Spyros,
  • Anita Büttner,
  • Athanassios Giannis and
  • Haralambos E. Katerinopoulos

Beilstein J. Org. Chem. 2017, 13, 952–959, doi:10.3762/bjoc.13.96

Graphical Abstract
  • . With an unsaturation degree of five, one carbonyl and two olefinic double bonds present, we propose as a possible structure the bicyclic system of costic acid shown in Figure 4. We applied the same numbering as was used in previous publications to allow for an easier comparison. 13C NMR experiments
PDF
Album
Supp Info
Full Research Paper
Published 18 May 2017

Opportunities and challenges for the sustainable production of structurally complex diterpenoids in recombinant microbial systems

  • Katarina Kemper,
  • Max Hirte,
  • Markus Reinbold,
  • Monika Fuchs and
  • Thomas Brück

Beilstein J. Org. Chem. 2017, 13, 845–854, doi:10.3762/bjoc.13.85

Graphical Abstract
  • naturally leads to the formation of tricyclic taxadiene [56] was achieved by exchanging a valin in position 584 with methionine. The resulting product was identified as a bicyclic diterpene of the verticillene type [51] (Scheme 2). A single residue switch in position 753 (W753H) presumably causes premature
  • stereoselective synthesis of (1R,3E,7E,11S,12S)-3,7,18-dolabellatriene, a bicyclic diterpene (Scheme 2). Dollabellanes derive mostly from marine organisms and display bioactivities such as antiviral and cytotoxic effects [59]. Dolabellatriene from a reprogrammed CotB2 contribute with antimicrobial activity
  • side: The natural product of wild-type cyclooctat-9-en-7-ol-synthase (CotB2) is a tricyclic diterpene whereas mutations in positions 107 and 288 yield in monocyclic cembrene A and bicyclic 3,7,18-dolabellatriene [57]. Changing the main product specificity of taxadiene synthase from Taxus brevifolia
PDF
Album
Review
Published 08 May 2017

Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

  • Matthew A. Horwitz,
  • Elisabetta Massolo and
  • Jeffrey S. Johnson

Beilstein J. Org. Chem. 2017, 13, 762–767, doi:10.3762/bjoc.13.75

Graphical Abstract
  • nucleophile. Mild reaction conditions allow the formation of diversely functionalized fused bicyclic lactones. The products participate in facially selective additions from the convex surface, leading to allylic alcohol derivatives. Keywords: conjugate addition; cyclohexadienones; dearomatization
  • ] nucleophiles using bifunctional cinchona alkaloid catalysts. The Sasai and Enders groups used a phosphinothiourea to enable a Rauhut–Currier reaction to form bicyclic enones [16]. The Tian and Lin group used alkyne-tethered cyclohexadienones in an arylrhodation/conjugate addition sequence that
  • developed an acyl anion addition promoted by N-heterocyclic carbenes (NHC) that furnished bicyclic furanones via Stetter addition [21]; later, the You group developed an extension of this theme using the same catalytic manifold [22]. More recently, the Corey group has enabled the enantioselective conjugate
PDF
Album
Supp Info
Letter
Published 24 Apr 2017

Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

  • Jan Szabo,
  • Julian Greiner and
  • Gerhard Maas

Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57

Graphical Abstract
  • (R = Me, CF3, Ph, ClCH2) in good yields was presented, although they were transformed further without isolation [14]. An old observation with a long-lasting impact was made by M. Busch who studied the reaction of formic acid with triphenylaminoguanidine: the originally assumed bicyclic constitution
PDF
Album
Supp Info
Full Research Paper
Published 22 Mar 2017

Synthesis of 1-indanones with a broad range of biological activity

  • Marika Turek,
  • Dorota Szczęsna,
  • Marek Koprowski and
  • Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

Graphical Abstract
PDF
Album
Review
Published 09 Mar 2017

The reductive decyanation reaction: an overview and recent developments

  • Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

Graphical Abstract
  • monodecyanated products 69a,b. Bicyclic lactones 70a,b are then obtained in 3 steps in 41% and 51% yields, respectively, from 69a,b. Later Curran’s group discovered that NHC-boryl radicals, generated from NHC-boranes (N-heterocyclic carbene boranes), abstracted the cyano group from various organic nitriles and
  • [106]. Synthesis of bicyclic lactones [119][120]. Reductive decyanation of malononitriles and cyanoacetates using NHC-boryl radicals (9 examples). For 74 and 75, isolated or NMR yields are given from 71 [121]. Proposed mechanism for the reduction by NHC-boryl radicals. The other possible pathway
PDF
Album
Review
Published 13 Feb 2017

Phosphated cyclodextrins as water-soluble chiral NMR solvating agents for cationic compounds

  • Cira Mollings Puentes and
  • Thomas J. Wenzel

Beilstein J. Org. Chem. 2017, 13, 43–53, doi:10.3762/bjoc.13.6

Graphical Abstract
  • , 18 and 20 where one of the P-CDs causes the largest enantiomeric differentiation. Substrates 21–26 contain bicyclic indoline, indane and indole rings. The P-CDs were only effective at causing enantiomeric differentiation in the 1H NMR spectra of a few resonances of 21, 24 and 26 (Table 4). With only
PDF
Album
Supp Info
Full Research Paper
Published 06 Jan 2017

Biochemical and structural characterisation of the second oxidative crosslinking step during the biosynthesis of the glycopeptide antibiotic A47934

  • Veronika Ulrich,
  • Clara Brieke and
  • Max J. Cryle

Beilstein J. Org. Chem. 2016, 12, 2849–2864, doi:10.3762/bjoc.12.284

Graphical Abstract
  • -Hpg7 peptide as well as the mono- and bicyclic products based on P450-catalysed turnover have been analysed in earlier studies [13][16][17]. Prior to the activity assay the substrate was loaded onto the A47934 PCP-X di-domain construct exhibiting maltose binding protein as N-terminal fusion partner
  • previous in vitro and in vivo experiments that indicate that the presence of the C-O-D ring is a prerequisite for the activity of subsequent P450 enzymes, such as StaF (Figure 4, Table 1 entry 1) [13][16][22][27][28][29][32]. Both mono- and bicyclic peptide products could be detected in samples with StaH
  • included in the turnover assay: given that we have demonstrated that StaH is capable of producing a C-O-D ring containing peptide from a linear precursor [12] and the lack of StaF activity against linear peptide substrates, we conclude that the formation of the bicyclic peptide is due to the activity of
PDF
Album
Supp Info
Full Research Paper
Published 27 Dec 2016

New syntheses of (±)-tashiromine and (±)-epitashiromine via enaminone intermediates

  • Darren L. Riley,
  • Joseph P. Michael and
  • Charles B. de Koning

Beilstein J. Org. Chem. 2016, 12, 2609–2613, doi:10.3762/bjoc.12.256

Graphical Abstract
  • of the naturally occurring indolizidine alkaloid (±)-tashiromine and its unnatural epimer (±)-epitashiromine are demonstrated through the use of enaminone chemistry. The impact of various electron-withdrawing substituents at the C-8 position of the indolizidine core on the preparation of the bicyclic
  • piperidine or a pyrrolidine-based precursor, with few reports of alternative approaches. The approach adopted by our research group to the synthesis of these and related bicyclic alkaloids takes advantage of enaminone chemistry [10][11][12][13][14][15][16][17][18][19]. Our interest in the enaminone manifold
  • electrophilic substituents are attached to the nitrogen, alkylating or acylating cyclisation onto the enamine carbon site leads to the formation of bicyclic systems with nitrogen located at the bridgehead. Our approach to the synthesis of indolizidines is thus unusual in that it entails the formation of the C-7
PDF
Album
Supp Info
Full Research Paper
Published 02 Dec 2016

Synthesis of polyhydroxylated decalins via two consecutive one-pot reactions: 1,4-addition/aldol reaction followed by RCM/syn-dihydroxylation

  • Michał Malik and
  • Sławomir Jarosz

Beilstein J. Org. Chem. 2016, 12, 2602–2608, doi:10.3762/bjoc.12.255

Graphical Abstract
  • well-known and recognizable group of carbasugars. The synthesis of these monocyclic compounds (such as 1 and 2, Figure 1) and evaluation of their biological properties remain a challenging and vital research area [8][9][10][11]. On the other hand, bicyclic analogs of cyclitols are not as well
  • -documented as their monocylic counterparts. However, polyhydroxylated derivatives of decalin and hydrindane are interesting synthetic targets, since they can be regarded as conformationally locked carbasugars (3 and 4, Figure 1) [12][13][14][15]. Indeed, some of the bicyclic carbasugars were proven to
  • possess strong and selective anti-glycosidase activity [16][17][18]. The polyoxygenated bicyclic motif is also found in some members of the nargenicin antibiotics family [19][20][21]. In our group, we have already proposed an approach to the synthesis of polyoxygenated bicyclic systems such as cis
PDF
Album
Supp Info
Full Research Paper
Published 01 Dec 2016
Graphical Abstract
  • intrinsic greenness potential based on threshold atom economy and reaction yield values. The application of this methodology was extended to several kinds of monocyclic and fused aromatic heterocyclic rings. We will report on the application of the integer partition algorithm to fused bicyclic and bridged
  • bicyclic ring frameworks elsewhere. Possible two-component couplings for various monocyclic rings frequently encountered in organic molecules. Synthesis bonds are shown as bolded bonds. Possible three-component couplings for various monocyclic rings frequently encountered in organic molecules. Synthesis
PDF
Album
Supp Info
Full Research Paper
Published 16 Nov 2016

Et3B-mediated and palladium-catalyzed direct allylation of β-dicarbonyl compounds with Morita–Baylis–Hillman alcohols

  • Ahlem Abidi,
  • Yosra Oueslati and
  • Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2402–2409, doi:10.3762/bjoc.12.234

Graphical Abstract
  • interesting synthesis of bicyclic dienones in a one-pot process involving the reaction of 2-(acetoxymethyl)cyclohex-2-enone with 1,3-dicarbonyl compounds using K2CO3 as a weak base. Later, Chamakh and Amri [38] have described a one-pot synthesis of (E)-4-alkylidene-2-cyclohexen-1-ones through a cross coupling
PDF
Album
Supp Info
Full Research Paper
Published 15 Nov 2016

Combined experimental and theoretical studies of regio- and stereoselectivity in reactions of β-isoxazolyl- and β-imidazolyl enamines with nitrile oxides

  • Ilya V. Efimov,
  • Marsel Z. Shafikov,
  • Nikolai A. Beliaev,
  • Natalia N. Volkova,
  • Tetyana V. Beryozkina,
  • Wim Dehaen,
  • Zhijin Fan,
  • Viktoria V. Grishko,
  • Gert Lubec,
  • Pavel A. Slepukhin and
  • Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2016, 12, 2390–2401, doi:10.3762/bjoc.12.233

Graphical Abstract
  • crystalline compounds, ligands for asymmetric synthesis, and they are also convenient reagents in organic synthesis [1]. Although bicyclic assemblies of azoles exhibit interesting chemical properties and biological activities [1][7][8][9][10][11] isoxazoles conjugated to other azole rings are poorly presented
PDF
Album
Supp Info
Full Research Paper
Published 15 Nov 2016

Methylenelactide: vinyl polymerization and spatial reactivity effects

  • Judita Britner and
  • Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 2378–2389, doi:10.3762/bjoc.12.232

Graphical Abstract
  • also shows additional postulated radical reactions including the formation of a bicyclic lactide radical to initiate the main polymerization. Since the spontaneous homolytically C–H cleavage may represent the first step in the reaction cascade, theoretical calculations on a DFT level were conducted
PDF
Album
Supp Info
Full Research Paper
Published 14 Nov 2016

Experimental and theoretical investigations into the stability of cyclic aminals

  • Edgar Sawatzky,
  • Antonios Drakopoulos,
  • Martin Rölz,
  • Christoph Sotriffer,
  • Bernd Engels and
  • Michael Decker

Beilstein J. Org. Chem. 2016, 12, 2280–2292, doi:10.3762/bjoc.12.221

Graphical Abstract
  • with aldehydes or ketones yielding bicyclic structures [25][26][27], or by the reduction of the corresponding dihydroquinazolinones [15][16][17] (Scheme 1). The aminal templates obtained can be used as starting materials for the synthesis of a broad spectrum of diverse structures. Oxidation reactions
PDF
Album
Supp Info
Full Research Paper
Published 31 Oct 2016

Isosorbide and dimethyl carbonate: a green match

  • Fabio Aricò and
  • Pietro Tundo

Beilstein J. Org. Chem. 2016, 12, 2256–2266, doi:10.3762/bjoc.12.218

Graphical Abstract
  • presence of the nitrogen bicyclic base DBU. It has been, in fact, reported that organic carbonates are activated by DBU via formation of an N-alkoxycarbonyl DBU derivative [67][68][69][70][71]. However, in this case study, DBU most probably promotes the formation of the methoxycarbonyl reaction
PDF
Album
Review
Published 26 Oct 2016

p-Nitrophenyl carbonate promoted ring-opening reactions of DBU and DBN affording lactam carbamates

  • Madhuri Vangala and
  • Ganesh P Shinde

Beilstein J. Org. Chem. 2016, 12, 2086–2092, doi:10.3762/bjoc.12.197

Graphical Abstract
  • towards highly electrophilic p-nitrophenyl carbonate derivatives with ring opening of the bicyclic ring to form corresponding substituted ε-caprolactam and γ-lactam derived carbamates. This simple method presents a unified strategy to synthesize structurally diverse ε-caprolactam and γ-lactam compounds
  • synthetically useful and strong neutral bases. Besides, DBU and DBN catalyze various organic reactions such as dehydrohalogenations [1], carbonylations [2], amidations [3] and Baylis–Hillman reactions [4]. These bicyclic amidines have been thought to be non-nucleophilic bases, but meanwhile numerous examples
  • nucleophiles towards halo derivatives of main group elements where the DBU and DBN bicyclic rings remained unaffected [10][11]. Later in 1994, Lammers et al. observed the nucleophilicity of amidine bases with 4-halo-3,5-dimethyl-1-nitro-1H-pyrazole and their subsequent ring opening leading to the lactam
PDF
Album
Supp Info
Full Research Paper
Published 26 Sep 2016

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

  • Lucie Brulíková,
  • Aidan Harrison,
  • Marvin J. Miller and
  • Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

Graphical Abstract
  • and experimental studies on the hetero-Diels–Alder reaction of the chiral 1-phosphono-1,3-butadiene 31 with nitroso dienophiles 32 (Scheme 6) [87]. The authors studied the reactivity of chiral 1-phosphonodienes modified with the bicyclic (R,R)-1,3,2-dioxaphospholane 31a or (R,R)-1,3,2
  • -diene (120) with the acylnitroso dienophile 119 (Scheme 24) [10]. The reaction proceeded in 81% overall yield with a major cycloadduct 121 and minor diastereomer 122, with 98% de. The absolute configuration of the major cycloadduct was confirmed by an independent synthesis from the known bicyclic (1R,4S
  • ][119]. Their utility was demonstrated by the synthesis of (+)-mannostatin A (138, Scheme 26) [120]. Here, the symmetric cycloaddition of the acylnitroso compound 117, derived from (R)-mandelic acid, to 1-(methylthio)cyclopenta-2,4-diene (135) predominantly afforded the bicyclic adduct 137 (in a ratio
PDF
Album
Review
Published 01 Sep 2016

A chiral analog of the bicyclic guanidine TBD: synthesis, structure and Brønsted base catalysis

  • Mariano Goldberg,
  • Denis Sartakov,
  • Jan W. Bats,
  • Michael Bolte and
  • Michael W. Göbel

Beilstein J. Org. Chem. 2016, 12, 1870–1876, doi:10.3762/bjoc.12.176

Graphical Abstract
  • natural products, have been used as chiral phase-transfer catalysts [12][13]. Bicyclic guanidines with five-membered rings are also known from the alkaloid isoalchornein [14][15]. In subsequent years, synthetic compounds (6–9) of this structural type have been developed as chiral Brønsted bases [16][17
PDF
Album
Supp Info
Full Research Paper
Published 19 Aug 2016

Mechanistic investigations on six bacterial terpene cyclases

  • Patrick Rabe,
  • Thomas Schmitz and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2016, 12, 1839–1850, doi:10.3762/bjoc.12.173

Graphical Abstract
  • bicyclic structure (Table 1). The signals of the hydrogens attached to each carbon were assigned by HSQC spectroscopy, while the 1H,1H-COSY revealed a contiguous spin system C3-2-1-6(-5)-7(-11(-13)-12)-8-9 and two separate methyl groups attached to the quarternary olefinic carbons (Figure 2a). The HMBC
PDF
Album
Supp Info
Full Research Paper
Published 15 Aug 2016

Three-component synthesis of highly functionalized aziridines containing a peptide side chain and their one-step transformation into β-functionalized α-ketoamides

  • Lena Huck,
  • Juan F. González,
  • Elena de la Cuesta and
  • J. Carlos Menéndez

Beilstein J. Org. Chem. 2016, 12, 1772–1777, doi:10.3762/bjoc.12.166

Graphical Abstract
  • involve the base-promoted formation of the bicyclic aziridine 4, where nitrogen conjugation to the adjacent carbonyl would be geometrically constrained. The associated increase in reactivity for this carbonyl would explain the complete selectivity of the diketopiperazine ring opening, with concomitant
PDF
Album
Supp Info
Full Research Paper
Published 08 Aug 2016

Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

  • Pramod R. Markad,
  • Navanath Kumbhar and
  • Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

Graphical Abstract
  • -dioxabicyclo[3.2.1]octane A could be glycosylated stereoselectively with the requisite nucleobase to give β-nucleoside pyranosyl skeleton 2. The bridged bicyclic system A was visualized from the azido diol B. Thus, hydrolysis of the 1,2-acetonide functionality in B will lead to in situ generation of
  • attack of the secondary hydroxy group to the oxocarbenium ion Y led to a stable six-membered pyranose ring compound thus shifting the equilibrium in favour of bridged bicyclic system 12/13. In order to validate the configurational assignments at the newly generated stereocenters, the coupling constants
PDF
Album
Supp Info
Full Research Paper
Published 05 Aug 2016
Other Beilstein-Institut Open Science Activities