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Search for "bicyclic" in Full Text gives 390 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO2 fixation by N-benzyl cyclic guanidine under dry and wet conditions

  • Yoshiaki Yoshida,
  • Naoto Aoyagi and
  • Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

Graphical Abstract
  • particular, CO2 capture–release behaviors of bicyclic and six-membered cyclic amidine derivatives have been well studied compared to that of five-membered derivatives, because the high ring strain of five-membered cyclic amidine derivatives was unfavorable for the binding between CO2 and the amidine moiety
  • guanidine derivative and CO2 was isolated and characterized for the first time, although there were a few reports about the bicyclic guanidine derivatives such as TBD. Results and Discussion CO2 fixation behavior of N-benzyl cyclic guanidine depending on dry and wet conditions First, CO2 fixation by N
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Published 23 Aug 2018

An amphiphilic pseudo[1]catenane: neutral guest-induced clouding point change

  • Tomoki Ogoshi,
  • Tomohiro Akutsu and
  • Tada-aki Yamagishi

Beilstein J. Org. Chem. 2018, 14, 1937–1943, doi:10.3762/bjoc.14.167

Graphical Abstract
  • /hydrophilic ratio in a molecule largely affects its assembled properties in aqueous media. In this study, we synthesized a new bicyclic compound which could dynamically change its hydrophobic/hydrophilic ratio by chemical stimulus. The bicyclic compound consisted of amphiphilic pillar[5]arene and hydrophobic
  • alkyl chain rings, and formed a self-inclusion structure in aqueous media, which was assigned as a pseudo[1]catenane structure. The hydrophobic chain ring was hidden inside the pillar[5]arene cavity in the pseudo[1]catenane structure, thus the bicyclic compound was soluble in water at 20 °C with a
  • aggregation of the hydrophobic alkyl chain rings, which induced insolubilization of the bicyclic compound in aqueous media at 20 °C and a decrease in its clouding point. Keywords: amphiphilic molecules; host–guest complexes; lower critical solution temperature; pillar[n]arenes; pseudo[1]catenane
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Published 26 Jul 2018

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3+ + 2]-cycloaddition/rearrangement reactions

  • Lin-bo Luan,
  • Zi-jie Song,
  • Zhi-ming Li and
  • Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

Graphical Abstract
  • , we wish to describe the synthesis of unprecedented tricyclic heterocycles, i.e., 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepinium salts 10 and the related neutral free base derivatives 13 via the cationic [3+ + 2]-cycloaddition/rearrangement reactions using the bicyclic 4-acetoxy-4-azo
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Published 18 Jul 2018

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

  • Fateh V. Singh,
  • Priyanka B. Kole,
  • Saeesh R. Mangaonkar and
  • Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

Graphical Abstract
  • of DMAP base. The spirocyclization reactions were performed in MeOH for 2 h at 0 °C and spirocyclic products 56 were isolated in good yields (Scheme 18). Additionally, fused bicyclic compounds 57 were also observed in few reactions in traces. The structure of the spiro β-lactam was confirmed by
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Published 17 Jul 2018

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

  • Yuichi Yoshimura,
  • Hideaki Wakamatsu,
  • Yoshihiro Natori,
  • Yukako Saito and
  • Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

Graphical Abstract
  • -thiosugar derivatives. We thus developed the first synthetic route accessing the 4-thiosugar derivative by way of bicyclic intermediate 8 from diacetoneglucose (5). Construction of the bicyclic ring of 8 was achieved by consecutive inter-/intramolecular SN2 reactions of the dimesylate derivative 7 obtained
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Published 28 Jun 2018

Two new 2-alkylquinolones, inhibitory to the fish skin ulcer pathogen Tenacibaculum maritimum, produced by a rhizobacterium of the genus Burkholderia sp.

  • Dandan Li,
  • Naoya Oku,
  • Atsumi Hasada,
  • Masafumi Shimizu and
  • Yasuhiro Igarashi

Beilstein J. Org. Chem. 2018, 14, 1446–1451, doi:10.3762/bjoc.14.122

Graphical Abstract
  • correspond to two rings, which constitutes a fused bicyclic structure as suggested by the number of available aromatic carbons (eleven). A 4-quinolone substructure was indicated by a peak-splitting at the 340–320 nm region in the UV spectrum (328 and 322 nm) [13]. Indeed, 1H NMR resonances at the down field
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Published 14 Jun 2018

Recent applications of chiral calixarenes in asymmetric catalysis

  • Mustafa Durmaz,
  • Erkan Halay and
  • Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

Graphical Abstract
  • coligand, their uranyl-(salen) derivatives 106a,b have been employed as models of the oxo-Mn(V)–(salen) oxidant species. The reactions were highly efficient in terms of productivity (up to 96% yield) and enantioselectivity (up to 93% ee) when rigid bicyclic alkenes such as 1,2-dihydronaphthalene and
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Published 08 Jun 2018

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

  • Veronika Hladíková,
  • Jiří Váňa and
  • Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

Graphical Abstract
  • bicyclic intermediate via a concerted [3 + 2]-cycloaddition followed by its very fast decomposition (extrusion of CO2) via a retro-Diels–Alder [4 + 2]-cycloaddition. The almost spontaneous extrusion of CO2 is caused by an energetically favorable aromatization occurring in this step leading to the formation
  • (80 °C) caused a decrease in the total yield by approximately 50%, with slightly increased selectivity (from 4.96 to 6.56). Lowering of the yield with increasing pressure confirms the reversibility of the first step (see Scheme 5) because of retardation of CO2 cleavage from the bicyclic intermediate
  • . Such reversibility was also suggested by Harrity et al. [92] on the basis of quantum calculations. While the formation of the bicyclic intermediate was calculated to be only slightly exergonic (−3.3 kcal·mol−1) the overall reaction is highly exothermic (−108.2 kcal·mol−1). These results show that minor
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Published 05 Jun 2018

Synthesis of pyrazolopyrimidinones using a “one-pot” approach under microwave irradiation

  • Mark Kelada,
  • John M. D. Walsh,
  • Robert W. Devine,
  • Patrick McArdle and
  • John C. Stephens

Beilstein J. Org. Chem. 2018, 14, 1222–1228, doi:10.3762/bjoc.14.104

Graphical Abstract
  • . Herein, we report such a strategy for the simple synthesis of functionalized pyrazolo[1,5-a]pyrimidinones that employs a one-pot microwave-assisted approach. Findings A number of synthetic approaches have been developed for the synthesis of privileged nitrogen-fused bicyclic systems such as the pyrazolo
  • the development of novel biologically active compounds based on the pyrazolopyrimidinone scaffold, we sought to develop a simple one-pot synthesis of the nitrogen-fused bicyclic system. In order to establish reaction conditions for this one-pot synthesis, we began by seeking general reaction
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Published 28 May 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
  • .Et2O in MeOH gave the expected dithioketal 154, whereas the reaction of tropone under similar conditions presented complications from rapid [1][7] sigmatropic shifts of unhindered alkylthio groups to give bicyclic 1,7-disubstituted cycloheptatrienes like 156 (Scheme 27). Leitich’s group reported the
  • underwent di-π-methane photo-rearrangement to 210–212 exclusively (Scheme 35). Moreover, Dastan’s group prepared bicyclic endoperoxide 213 in 74% yield from 2,3-benzotropone (12) via tetraphenylporphyrine (TPP)-sensitized photo-oxygenation (Scheme 35) [149]. 3.2.4. Miscellaneous transformations: Machiguchi
  • -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
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Published 23 May 2018

Preparation, structure, and reactivity of bicyclic benziodazole: a new hypervalent iodine heterocycle

  • Akira Yoshimura,
  • Michael T. Shea,
  • Cody L. Makitalo,
  • Melissa E. Jarvi,
  • Gregory T. Rohde,
  • Akio Saito,
  • Mekhman S. Yusubov and
  • Viktor V. Zhdankin

Beilstein J. Org. Chem. 2018, 14, 1016–1020, doi:10.3762/bjoc.14.87

Graphical Abstract
  • , Duluth, MN 55811, USA, Division of Applied Chemistry, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan 10.3762/bjoc.14.87 Abstract A new bicyclic organohypervalent iodine heterocycle derivative of benziodazole was prepared by
  • preparation of several bicyclic benziodoxoles 3 starting from 2-iodoisophthalic acid (2, Scheme 1b). These bicyclic benziodoxoles 3 can be used as efficient coupling reagents for the direct condensation reaction between carboxylic acids and alcohols or amines to provide esters, macrocyclic lactones, or amides
  • knowledge, all known benziodazoles have a mono-heterocyclic structure, and bi-heterocyclic benziodazole derivatives similar to the bicyclic benziodoxole 3 have never been reported. In this paper, we report the synthesis, structural characterization, and reactivity of a novel bicyclic benziodazole derivative
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Published 08 May 2018

An efficient and facile access to highly functionalized pyrrole derivatives

  • Meng Gao,
  • Wenting Zhao,
  • Hongyi Zhao,
  • Ziyun Lin,
  • Dongfeng Zhang and
  • Haihong Huang

Beilstein J. Org. Chem. 2018, 14, 884–890, doi:10.3762/bjoc.14.75

Graphical Abstract
  • decomposition pathways, we increased the amount of 9a up to 1.5 equivalents, which delivered the bicyclic pyrrolidine 11a in excellent yield (82%, Table 2, entry 5). Prolonging the reaction time from 3 h to 6 h had no influence on the yield (Table 2, entry 6), which demonstrated that appropriate increase on the
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Published 20 Apr 2018

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue

  • Romain Sallio,
  • Stéphane Lebrun,
  • Frédéric Capet,
  • Francine Agbossou-Niedercorn,
  • Christophe Michon and
  • Eric Deniau

Beilstein J. Org. Chem. 2018, 14, 593–602, doi:10.3762/bjoc.14.46

Graphical Abstract
  • -transfer catalyst; 3-substituted isoindolinones; Introduction Isoindolinones I (Figure 1), e.g., 2,3-dihydro-1H-isoindol-1-ones, also called phthalimidines are bicyclic lactams whose molecular structure is the basis of a wide range of alkaloids and biologically active compounds [1][2][3][4][5][6][7][8][9
  • -substituted isoindolinones 1 and 2 could be obtained in high enantioselectivities from the intermediates (2R,3S)-3–5 after removal of the chiral auxiliary (Scheme 1). (2R,3S)-bicyclic lactams 3–5 could be prepared by the asymmetric intramolecular organo-catalyzed aza-Michael reaction of (R)-benzamides 6–8
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Published 09 Mar 2018

Synthesis and biological evaluation of RGD and isoDGR peptidomimetic-α-amanitin conjugates for tumor-targeting

  • Lizeth Bodero,
  • Paula López Rivas,
  • Barbara Korsak,
  • Torsten Hechler,
  • Andreas Pahl,
  • Christoph Müller,
  • Daniela Arosio,
  • Luca Pignataro,
  • Cesare Gennari and
  • Umberto Piarulli

Beilstein J. Org. Chem. 2018, 14, 407–415, doi:10.3762/bjoc.14.29

Graphical Abstract
  • bicyclic octapeptide toxin belonging to the amatoxin family, found in Amanita Phalloides (death cap mushroom), see Figure 1 [1]. Its mechanism of action consists in the inhibition of cellular transcription by an effective blocking of RNA polymerase II, which is present in the nuclei of eukaryotic cells and
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Published 14 Feb 2018

Novel amide-functionalized chloramphenicol base bifunctional organocatalysts for enantioselective alcoholysis of meso-cyclic anhydrides

  • Lingjun Xu,
  • Shuwen Han,
  • Linjie Yan,
  • Haifeng Wang,
  • Haihui Peng and
  • Fener Chen

Beilstein J. Org. Chem. 2018, 14, 309–317, doi:10.3762/bjoc.14.19

Graphical Abstract
  • conveniently converted into the corresponding monoester products in high yields and enantioselectivities. Notably, bicyclic anhydrides (Table 2, entries 1 and 2) and tricyclic anhydrides (Table 2, entries 3 and 4) were more reactive than mono-cyclic anhydrides (Table 2, entries 5–12). In the case of mono
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Published 31 Jan 2018

Fluorogenic PNA probes

  • Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

Graphical Abstract
  • applications, it means that tC–PNA alone is not useful as a fluorogenic probe. The related tri- or bicyclic thymine analogues tT and bT (without the additional aromatic ring) pair specifically with dA when incorporated into aegPNA, but their fluorescence properties have not been reported [184]. PNA carrying
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Published 29 Jan 2018

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

  • Ranjana Aggarwal and
  • Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

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Published 25 Jan 2018

Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)

  • Michał Nowacki and
  • Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14

Graphical Abstract
  • unprotected indoloquinoline 12 and its N-oxide 13 in 26 and 12% yields, respectively (Scheme 4). To extend the scope of the reaction to more active nitroarenes, we used slightly modified reaction conditions using DBU as a base. Earlier we have found that in the reactions of bicyclic nitroarenes this base was
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Published 23 Jan 2018

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

  • Irwan Iskandar Roslan,
  • Kian-Hong Ng,
  • Gaik-Khuan Chuah and
  • Stephan Jaenicke

Beilstein J. Org. Chem. 2017, 13, 2739–2750, doi:10.3762/bjoc.13.270

Graphical Abstract
  • -aminobenzothiazole with acetophenones [55] or aldehydes and nitroalkanes [56]. Because the bicyclic structure of 2-aminobenzothiazole is more stable than aminopyridines and thioureas, the nucleophilicity of the aromatic N atom is reduced. A stronger base, KOt-Bu, is therefore needed for in situ bromination to form
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Published 18 Dec 2017

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

  • Anna Kuźnik,
  • Roman Mazurkiewicz and
  • Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

Graphical Abstract
  • intramolecular Wittig reaction. The yields of the product ranged between 6 and 95% [13]. 2.2.3. Reactions with nitrogen nucleophiles: The reaction of vinylphosphonium salt with 2-pyrrolocarbaldehyde in the presence of sodium hydride as described by Schweizer et al. provided bicyclic pyrrole derivatives 47 in 25
  • –87% yields (Scheme 32) [2][42]. Similarly, Hewson and co-workers synthesized bicyclic 2-pyrrolidinone derivatives 48 from 5-acetyl-2-pyrrolidinone in a yield of 40–68% (Scheme 33) [48]. In 1994 Burley and Hewson reported a reaction of vinylphosphonium salt with nitrogen nucleophiles, obtained by
  • synthesis of resonance-stabilized phosphorus ylides 81 (Scheme 51). The obtained ylides underwent further cyclization by the intramolecular acylation of the primary amino group to give the final bicyclic products 82 in 85–90% yields [67]. The synthesis of resonance-stabilized phosphorus ylides via the
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Published 15 Dec 2017

A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

  • Dmitry Yu. Vandyshev,
  • Khidmet S. Shikhaliev,
  • Andrey Yu. Potapov,
  • Michael Yu. Krysin,
  • Fedor I. Zubkov and
  • Lyudmila V. Sapronova

Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252

Graphical Abstract
  • -addition by the activated C=C double bond and subsequent intramolecular recyclization of the intermediate with the amino group involved. Keywords: cascade reaction; diaminoimidazoles; HPLC–HRESIMS; imidazo[1,5-b]pyridazines; itaconimides; Introduction Among the numerous bicyclic fused imidazole
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Published 30 Nov 2017

15N-Labelling and structure determination of adamantylated azolo-azines in solution

  • Sergey L. Deev,
  • Alexander S. Paramonov,
  • Tatyana S. Shestakova,
  • Igor A. Khalymbadzha,
  • Oleg N. Chupakhin,
  • Julia O. Subbotina,
  • Oleg S. Eltsov,
  • Pavel A. Slepukhin,
  • Vladimir L. Rusinov,
  • Alexander S. Arseniev and
  • Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

Graphical Abstract
  • between them. The rotation of the N-adamantyl substituents around the N–C1' bond in the bulky bicyclic heterocycles is likely hindered, and the observed conformational heterogeneity corresponds to the different rotameric configurations of the substituent. To test this hypothesis, additional NMR
  • JCN) to provide structural information about the N-adamantylation sites in bicyclic heterocycles. The previous studies of azolo[5,1-c][1,2,4]triazin-7-ones, 1,2,4-triazolo[1,5-a]pyrimidin-7-ones and tetrazolo-azines revealed that the 13C chemical shifts of the nearest carbon atoms to N-alkyl fragments
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Published 29 Nov 2017

Herpetopanone, a diterpene from Herpetosiphon aurantiacus discovered by isotope labeling

  • Xinli Pan,
  • Nicole Domin,
  • Sebastian Schieferdecker,
  • Hirokazu Kage,
  • Martin Roth and
  • Markus Nett

Beilstein J. Org. Chem. 2017, 13, 2458–2465, doi:10.3762/bjoc.13.242

Graphical Abstract
  • NMR data for 2 [22] confirmed our assignment of the octahydro-1H-indene skeleton. The biosynthesis of the bicyclic ring system in 2 was previously proposed to occur via an α-cadinol intermediate, which undergoes a ring contraction reaction [19]. The cadinane family of sesquiterpenes, which also
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Published 17 Nov 2017

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

  • Jan Podlesný,
  • Lenka Dokládalová,
  • Oldřich Pytela,
  • Adam Urbanec,
  • Milan Klikar,
  • Numan Almonasy,
  • Tomáš Mikysek,
  • Jaroslav Jedryka,
  • Iwan V. Kityk and
  • Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

Graphical Abstract
  • , diketopyrrolopyrroles (DPP) represent an unique class of organic molecules based on central, fused, and conjugated bicyclic lactams of 2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione. After its serendipitous discovery by Farnum et al. in 1974 [1] and subsequent first applications as organic, insoluble, and high-performance
  • -photon absorbers (2PA). In this respect, the central DPP bicyclic lactam is often decorated with electron donors such as alkoxy- or dialkylamino groups [11][12], triphenylamine [13][14], heterocyclic carbazole [15], thiophene [16][17], furan [18], and organometallic ferrocene [19]. 2PA-active DPPs were
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Published 08 Nov 2017

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

  • Magdalena Ceborska,
  • Magdalena Zimnicka,
  • Aneta Aniela Kowalska,
  • Kajetan Dąbrowa and
  • Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

Graphical Abstract
  • changes of chemical shifts for the guest molecule in regard to FA appear only for three protons (aliphatic FA#H4 protons and phenolic FA#H6 and FA#H7) while changes for PTX appear in the same region but additionally for the belonging to the bicyclic heteroaromatic proton PTX#H4. It means that either this
  • obtained results strongly support the assumption that not a whole PTX molecule is encapsulated inside the β-CD cavity, and, instead, the complex is formed through inclusion of a major part of aromatic parts of the molecule (both bicyclic heteroaromatic ring and phenolic ring), whereas aliphatic chain with
  • guest compounds with the changes being larger for the PTX molecule. Moreover, a quite substantial change in chemical shift upon complexation is observed for the PTX#H4 proton of the bicyclic part of the PTX molecule (0.09 ppm), whereas for FA the corresponding change of the FA#H3 proton equals only 0.05
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Published 25 Oct 2017
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