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Search for "cyclization reaction" in Full Text gives 204 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Synthesis of 2-trifluoromethylpyrazolo[5,1-a]isoquinolines via silver triflate-catalyzed or electrophile-mediated one-pot tandem reaction

  • Xiaoli Zhou,
  • Meiling Liu,
  • Puying Luo,
  • Yingjun Lai,
  • Tangtao Yang and
  • Qiuping Ding

Beilstein J. Org. Chem. 2014, 10, 2286–2292, doi:10.3762/bjoc.10.238

Graphical Abstract
  • 1i reacted with 2, leading to the desired pyrazolo[5,1-a]isoquinoline 3i in 90% yield (Table 2, entry 9). Subsequently, based on our previous reports on electrophile-mediated electrophilic cyclization reaction [28][29], one-pot tandem electrophilic cyclization/[3 + 2] cycloaddition of N’-(2
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Published 30 Sep 2014

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

  • Jan Szabo,
  • Kerstin Karger,
  • Nicolas Bucher and
  • Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

Graphical Abstract
  • (benzylamino)guanidinium chloride and aryl isothiocyanates. Here, a cyclization reaction occurred after thiocarbamoylation of the first NH2 group. The diverse reaction routes reported in this paper nicely demonstrate the versatility of TAG-derived 1,2,3-tris(alkylamino)guanidinium ions respect to synthetic
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Published 24 Sep 2014

Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones

  • Andrea Temperini,
  • Massimo Curini,
  • Ornelio Rosati and
  • Lucio Minuti

Beilstein J. Org. Chem. 2014, 10, 1267–1271, doi:10.3762/bjoc.10.127

Graphical Abstract
  • the oxidative-cyclization reaction of 1j not only favoured the oxidation reaction, but also suppressed the β-elimination side reaction of the selenoxide intermediate [14]. Thus tetrahydrofuran 3j was obtained in 69% yield (Table 2, entry 7) as the sole product. It is interesting to note that N
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Letter
Published 02 Jun 2014

Atherton–Todd reaction: mechanism, scope and applications

  • Stéphanie S. Le Corre,
  • Mathieu Berchel,
  • Hélène Couthon-Gourvès,
  • Jean-Pierre Haelters and
  • Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

Graphical Abstract
  • expected phosphoramidate was jointly isolated with 5 to 10% of thiophosphoramidate resulting from a cyclization reaction. The chiral phosphoramidates (Scheme 32-ii and iii) were tested as a chiral catalyst for the nucleophilic addition of diethylzinc [107] on benzaldehyde or for the asymmetric borane
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Published 21 May 2014

Theoretical studies on the intramolecular cyclization of 2,4,6-t-Bu3C6H2P=C: and effects of conjugation between the P=C and aromatic moieties

  • Masaaki Yoshifuji and
  • Shigekazu Ito

Beilstein J. Org. Chem. 2014, 10, 1032–1036, doi:10.3762/bjoc.10.103

Graphical Abstract
  • [10][14]. As an alternative reaction of phosphanylidenecarbenoid, we have previously found the intramolecular cyclization reaction affording 6,8-di-tert-butyl-3,4-dihydro-4,4-dimethyl-1-phosphanaphthalene (2) putatively through formation of phosphanylidenecarbene 1 generated from Mes*P=C(Br)Li (Scheme
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Published 07 May 2014

Allenylphosphine oxides as simple scaffolds for phosphinoylindoles and phosphinoylisocoumarins

  • G. Gangadhararao,
  • Ramesh Kotikalapudi,
  • M. Nagarjuna Reddy and
  • K. C. Kumara Swamy

Beilstein J. Org. Chem. 2014, 10, 996–1005, doi:10.3762/bjoc.10.99

Graphical Abstract
  • , over the last decade, allenes have attained a prominent position in organic transformations like cycloaddition, cycloisomerization, base or metal-catalyzed reactions [5][6][7]. In particular, cyclization reaction of allenes has emerged as a valuable tool in developing different methods leading to
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Published 02 May 2014

On the mechanism of photocatalytic reactions with eosin Y

  • Michal Majek,
  • Fabiana Filace and
  • Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97

Graphical Abstract
  • phenanthrene synthesis [19]. A solution of o-biphenyldiazonium tetrafluoroborate in acetonitrile showed strong absorption between 400–500 nm with all light at the UV–vis edge at 400 nm being completely absorbed. This again indicates that direct photocleavage of the C–N bond might be operating. The cyclization
  • reaction with ethyl propiolate according to the literature protocol [19] but in the absence of eosin Y did not afford any phenanthrene product (Scheme 5). Instead, a Ritter-type reaction proceeded to give the corresponding acetanilide after aqueous work-up which is consistent with the original report by
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Published 30 Apr 2014

Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C36H12 open geodesic polyarene

  • Hee Yeon Cho,
  • Ronald B. M. Ansems and
  • Lawrence T. Scott

Beilstein J. Org. Chem. 2014, 10, 956–968, doi:10.3762/bjoc.10.94

Graphical Abstract
  • -trichlorodecacyclene (12) by FVP at 1100 °C (Scheme 3) [20]. The importance of strategically functionalizing hydrocarbon precursors in a way that will generate radical centers where new bonds are to be formed by FVP is dramatically illustrated by the vastly improved efficiency of this triple cyclization reaction when
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Published 28 Apr 2014

The influence of intraannular templates on the liquid crystallinity of shape-persistent macrocycles

  • Joscha Vollmeyer,
  • Ute Baumeister and
  • Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 910–920, doi:10.3762/bjoc.10.89

Graphical Abstract
  • templates of being robust against solvent or temperature changes and will still be applicable at elevated temperatures. The bisacetylenes can be prepared independently and attached to the template just prior to the cyclization reaction or, and this is done here, the (template bound) oligoacetylene is
  • oligoether template crosses the ring, no lc behavior is observed. In both cases an induced non-planarity of the macrocycles is assumed. Shape-persistent macrocycles with different peripheral side groups and intraannular templates. GPC elugrams of the crude product of the cyclization reaction of 1a (—) and 1d
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Published 23 Apr 2014

Aza-Diels–Alder reaction between N-aryl-1-oxo-1H-isoindolium ions and tert-enamides: Steric effects on reaction outcome

  • Amitabh Jha,
  • Ting-Yi Chou,
  • Zainab ALJaroudi,
  • Bobby D. Ellis and
  • T. Stanley Cameron

Beilstein J. Org. Chem. 2014, 10, 848–857, doi:10.3762/bjoc.10.81

Graphical Abstract
  • the N-aryl group undergo intramolecular electrophilic addition to the alkene yielding isoindolo[2,1-a]quinolines under acidic conditions [18]. Isoindolo[2,1-a]quinolone cores have also been prepared via an aldol-type intramolecular cyclization reaction of N-(2-acetylaryl)phthalimide under anhydrous
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Published 14 Apr 2014

First synthesis of meso-substituted pyrrolo[1,2-a]quinoxalinoporphyrins

  • Dileep Kumar Singh and
  • Mahendra Nath

Beilstein J. Org. Chem. 2014, 10, 808–813, doi:10.3762/bjoc.10.76

Graphical Abstract
  • synthesis of novel meso-substituted pyrrolo[1,2-a]quinoxalinoporphyrins (4a–h) began via the Pictet–Spengler cyclization reaction [50][51] of 5-(3-amino-4-(pyrrol-1-yl)phenyl)-10,15,20-triphenylporphyrin (3) with various aromatic aldehydes by using 2% TFA in dichloromethane as an acidic catalyst at 0 °C for
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Published 08 Apr 2014

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

  • Gijs Koopmanschap,
  • Eelco Ruijter and
  • Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

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Published 04 Mar 2014

Silver and gold-catalyzed multicomponent reactions

  • Giorgio Abbiati and
  • Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

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Published 26 Feb 2014

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

  • Alexander O. Terent'ev,
  • Dmitry A. Borisov,
  • Vera A. Vil’ and
  • Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

Graphical Abstract
  • substituent, are inert under the reported conditions. Haloperoxidation reaction that is accompanied by intramolecular ring closure represents another version of the cyclization reaction. For example, the reaction of bromine with unsaturated hydroperoxide 146 (produced by reaction of 1,4,5,8
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Published 08 Jan 2014

An efficient method for the construction of polysubstituted 4-pyridones via self-condensation of β-keto amides mediated by P2O5 and catalyzed by zinc bromide

  • Liquan Tan,
  • Peng Zhou,
  • Cui Chen and
  • Weibing Liu

Beilstein J. Org. Chem. 2013, 9, 2681–2687, doi:10.3762/bjoc.9.304

Graphical Abstract
  • Liquan Tan Peng Zhou Cui Chen Weibing Liu School of Chemistry and Life Science, Guangdong University of Petrochemical Technology, 2 Guangdu Road, Maoming 525000, China 10.3762/bjoc.9.304 Abstract A self-condensation cyclization reaction mediated by phosphorus pentoxide (P2O5) and catalyzed by
  • -condensation cyclization reaction did not occur in the absence of ZnBr2 (Table 1, entry 1) or P2O5 (Table 1, entry 3) at room temperature. Notable efficacy was achieved when increasing the reaction temperature to 100 °C for 4 h and afforded the desired product 1,4-dihydro-2,6-dimethyl-4-oxo-N,1
  • , entry 7). To explore the substrate scope and limitations of this self-condensation cyclization reaction, a range of N-aryl β-keto amides were then examined under the optimal reaction conditions. The results are shown in Scheme 3. The results indicated that a variety of substituted N-aryl acetoacetamides
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Published 28 Nov 2013

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

  • Sudipta Pathak,
  • Kamalesh Debnath and
  • Animesh Pramanik

Beilstein J. Org. Chem. 2013, 9, 2344–2353, doi:10.3762/bjoc.9.269

Graphical Abstract
  • -catalyzed oxidative lactonization or an intramolecular cyclization reaction of δ-ketoaldehydes [12], a ruthenium-catalyzed aerobic oxidative cyclization of aromatic acids with alkynes [13], an FeCl3-promoted regioselective annulation of o-(1-alkynyl)benzoates with disulfides [14], a Heck–Matsuda cyclization
  • reaction [15], a 6-endo-dig cyclization of heteroaryl esters to alkynes [16], or a Pd(II)-mediated cyclization of o-allylbenzaldehydes [17]. Salvinorin A, a natural product isolated from the hallucinogenic sage Salvia divinorum, which also contains a saturated isocoumarin ring, has been synthesized [18
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Published 04 Nov 2013

Gold(I)-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl) ethers: synthesis of 3-iodo-2H-chromene derivatives

  • Pablo Morán-Poladura,
  • Eduardo Rubio and
  • José M. González

Beilstein J. Org. Chem. 2013, 9, 2120–2128, doi:10.3762/bjoc.9.249

Graphical Abstract
  • competition with a direct Friedel–Crafts-type cyclization reaction yielding 3. In previous work dealing with the cyclization of N-(3-iodoprop-2-ynyl)-N-tosylanilines to give related 1,2-dihydroquinolines (Scheme 4A, X = NTs) [43], we documented for a phosphite-based gold-catalyst, which render a more
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Published 16 Oct 2013

One-step synthesis of pyridines and dihydropyridines in a continuous flow microwave reactor

  • Mark C. Bagley,
  • Vincenzo Fusillo,
  • Robert L. Jenkins,
  • M. Caterina Lubinu and
  • Christopher Mason

Beilstein J. Org. Chem. 2013, 9, 1957–1968, doi:10.3762/bjoc.9.232

Graphical Abstract
  • continuous flow reactor examined the cyclodehydration of Bohlmann–Rahtz aminodienone intermediates in the presence of a Brønsted acid catalyst [44][45]. This relatively simple cyclization reaction was utilized previously as we had already established its facility under microwave irradiation and so it
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Published 30 Sep 2013

Continuous flow photocyclization of stilbenes – scalable synthesis of functionalized phenanthrenes and helicenes

  • Quentin Lefebvre,
  • Marc Jentsch and
  • Magnus Rueping

Beilstein J. Org. Chem. 2013, 9, 1883–1890, doi:10.3762/bjoc.9.221

Graphical Abstract
  • backbone functionalized phenanthrenes and helicenes of various sizes in good yields. Keywords: continuous-flow reactor; flow chemistry; helicenes; light-driven cyclization reaction; photocyclization; stilbenes; Introduction Phenanthrenes are versatile intermediates toward polycyclic aromatic hydrocarbons
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Published 17 Sep 2013
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  • vinylphosphonate (16), and diethyl 2-methylallylphosphonate (18) in EtONa solution to give the fused imidazophosphono-substituted compounds 17 (76%) and 19 (74%). Obviously, according to Scheme 6, the coupling cyclization reaction of 1b with 16 and auto-oxidation resulted in formation of the final product 17 in
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Published 22 Aug 2013

Anodic coupling of carboxylic acids to electron-rich double bonds: A surprising non-Kolbe pathway to lactones

  • Robert J. Perkins,
  • Hai-Chao Xu,
  • John M. Campbell and
  • Kevin D. Moeller

Beilstein J. Org. Chem. 2013, 9, 1630–1636, doi:10.3762/bjoc.9.186

Graphical Abstract
  • have the olefin functionalized with an alcohol and a methoxy group indicating that the initial oxidative cyclization had occurred. In this case, the slightly higher oxidation potential measured for the substrate (+0.71 V versus Ag/AgCl) is consistent with a slightly slower cyclization reaction
  • oxidation potential [21]. The seven-membered ring cyclization arising from the oxidation of 19b would be significantly slower, giving rise to a higher oxidation potential. Given the evidence for a fast cyclization reaction, we attributed the challenges associated with the styrene cyclizations to a problem
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Published 09 Aug 2013

Total synthesis of ochnaflavone

  • Monica M. Ndoile and
  • Fanie R. van Heerden

Beilstein J. Org. Chem. 2013, 9, 1346–1351, doi:10.3762/bjoc.9.152

Graphical Abstract
  • decomposition was still observed. The reaction was repeated under same conditions (DMSO/I2) at various temperatures, and it was observed that at lower temperatures, a longer time was taken for the starting material to be consumed, but it still resulted in a mixture of products. The cyclization reaction was
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Published 08 Jul 2013

Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts

  • Mostafa Kiamehr,
  • Firouz Matloubi Moghaddam,
  • Satenik Mkrtchyan,
  • Volodymyr Semeniuchenko,
  • Linda Supe,
  • Alexander Villinger,
  • Peter Langer and
  • Viktor O. Iaroshenko

Beilstein J. Org. Chem. 2013, 9, 1119–1126, doi:10.3762/bjoc.9.124

Graphical Abstract
  • different substituents in positions 1, 2, 3 and 4 were prepared by alkylation of the parental commercially available pyridines (see Supporting Information File 1, Table S1). The results of this cyclization reaction (Scheme 2) are summarized in Figure 1. Generally the reaction was complete in 24 hours and
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Published 10 Jun 2013

Gold-catalyzed oxycyclization of allenic carbamates: expeditious synthesis of 1,3-oxazin-2-ones

  • Benito Alcaide,
  • Pedro Almendros,
  • M. Teresa Quirós and
  • Israel Fernández

Beilstein J. Org. Chem. 2013, 9, 818–826, doi:10.3762/bjoc.9.93

Graphical Abstract
  • -1,3-oxazinan-2-one) 3g through a two-fold cyclization. This product particularly underlines the power of the present cyclization reaction, as none of the conventional methods would allow its synthesis with such great ease. Interestingly, as a first try, we were pleased to notice that the reaction of
  • vacant d atomic orbital of the gold atom in INT1-B [79]. Both complexes can undergo the corresponding oxyauration cyclization reaction. Thus, INT1-A is converted into INT2-A in a slightly exergonic process (ΔGR,298 = −0.4 kcal/mol) through the saddle point TS1-A, which is associated with the 6-endo-dig
  • cyclization. Similarly, INT1-B is transformed into INT2-B in a slightly endergonic process (ΔGR,298 = +0.9 kcal/mol) via TS1-B, associated with the 6-exo-dig cyclization reaction. From the data in Figure 1, it becomes obvious that the 6-endo-dig transformation is kinetically favored over the 6-exo-dig
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Published 26 Apr 2013

Synthesis of meso-substituted dihydro-1,3-oxazinoporphyrins

  • Satyasheel Sharma and
  • Mahendra Nath

Beilstein J. Org. Chem. 2013, 9, 496–502, doi:10.3762/bjoc.9.53

Graphical Abstract
  • NaBH4 in a chloroform/methanol mixture at 25 °C produced meso-substituted aminoporphyrins 4 and 5, respectively. In the final step, these aminoporphyrins underwent a condensation cyclization reaction with aldehydes in THF under reflux to form new dihydro-1,3-benzoxazinoporphyrins 6–9 in good yields
  • condensation–cyclization reaction of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin (1) with α- or β-naphthol and formaldehyde in THF under reflux. After reaction with Zn(OAc)2·2H2O in CHCl3/MeOH mixture, the free-base naphthoxazinoporphyrins 14 and 16 underwent zinc insertion to afford zinc (II) dihydro-1,3
  • -naphthoxazinoporphyrins 15 and 17 in 90–92% yields as depicted in Scheme 2. In addition, the dimeric naphthoxazinoporphyrins 18–20 were also prepared in moderate yields through one-pot Mannich-type condensation–cyclization reaction of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin (1) with α,α- or β,β- or α,β
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Published 07 Mar 2013
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