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Search for "nitro" in Full Text gives 513 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

  • Andreas H. Heindl and
  • Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

Graphical Abstract
  • ). Starting from 3,5-disubstituted nitrosobenzene E, consecutive Bayer–Mills and deprotection reactions would lead to the target compound 3 in five steps. Furthermore, by using nitrosoarene E, the selective installment of the amine groups, e.g., via acetamide- and nitro group-carrying intermediates, could be
  • . The azobenzene building block 8, with an unsubstituted phenyl ring and two orthogonal nitrogen substituents in the 3- and 5-position (Scheme 3), was prepared. The synthesis commenced with the acetylation of 3,5-dinitroaniline (4) in 95% yield, followed by the selective reduction of one nitro group
  • (E)-N-(3-nitro-5-(phenyldiazenyl)phenyl)acetamide (8), the reduction of the nitro group was attempted. However, the literature-known procedure of using sodium hydrosulfide did not yield the desired (E)-N-(3-amino-5-(phenyldiazenyl)phenyl)acetamide (9). Alternative reduction attempts, such as using Pd
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Published 03 Jan 2020

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

  • László Orha,
  • József M. Tukacs,
  • László Kollár and
  • László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

Graphical Abstract
  • ][4EtOV] were subjected to the coupling reaction under identical conditions. By comparison of the efficiency of conversion of iodobenzene and its electron-donating 4-methoxy (1d) and electron-withdrawing 4-nitro (1m) derivatives with different aliphatic acetylenes (4, 6, and 8), no significant differences
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Published 03 Dec 2019

Safe and highly efficient adaptation of potentially explosive azide chemistry involved in the synthesis of Tamiflu using continuous-flow technology

  • Cloudius R. Sagandira and
  • Paul Watts

Beilstein J. Org. Chem. 2019, 15, 2577–2589, doi:10.3762/bjoc.15.251

Graphical Abstract
  • 1a is a potentially explosive compound because of its nitro and azide moieties [14] and its safety concerns need to be dealt with for large scale synthesis. Safety in this reaction was achieved by in situ formation and consumption in flow of the hazardous intermediates (azide 1a and isocyanate 1b
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Published 30 Oct 2019

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

  • Thines Kanagasundaram,
  • Antje Timmermann,
  • Carsten S. Kramer and
  • Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

Graphical Abstract
  • conditions applied for the cross coupling of the triflate were similar to those published by Calitree and Detty for the coupling of the triflates derived from the O, S, Se, and Te-xanthones 16 with various phenylboroxines (bearing nitro, carboxylic acid, methyl and methoxy substituents) [29]. Here yields of
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Published 29 Oct 2019

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

  • Xavier Gómez-Santacana,
  • Sabrina M. de Munnik,
  • Tamara A. M. Mocking,
  • Niels J. Hauwert,
  • Shanliang Sun,
  • Prashanna Vijayachandran,
  • Iwan J. P. de Esch,
  • Henry F. Vischer,
  • Maikel Wijtmans and
  • Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

Graphical Abstract
  • -nitrobenzaldehyde (8a) to give the corresponding tertiary amine 9a in high yield. The nitro group of 9a was subsequently reduced by SnCl2 in high yield. The resulting aniline 10a was used to obtain the azo compounds 12a–e in varying yields through a Mills reaction with the corresponding nitroso compounds 11a–e
  • performed following the strategies shown in Scheme 1 as disclosed for compounds 2a–e. Briefly, a reductive amination of 7 and 8b gave nitro compound 9b, which after reduction to 10b, coupling with nitroso compounds 11a–e to 13a–e and methylation gave iodide salts 3a–e with purities of trans-isomers ≥99% and
  • ). The electron-donating groups in this series (Me and OMe) also increase the electron density of the azobenzene system. The synthesis of 4a–d and 4f–i was performed following the route shown in Scheme 1. Briefly, 7 was used in a reductive amination with 2-chloro-3-nitrobenzaldehyde (8c) to give nitro
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Published 23 Oct 2019

Cyclopropanation–ring expansion of 3-chloroindoles with α-halodiazoacetates: novel synthesis of 4-quinolone-3-carboxylic acid and norfloxacin

  • Sara Peeters,
  • Linn Neerbye Berntsen,
  • Pål Rongved and
  • Tore Bonge-Hansen

Beilstein J. Org. Chem. 2019, 15, 2156–2160, doi:10.3762/bjoc.15.212

Graphical Abstract
  • [33]. This transformation is particularly well suited for 4-chloroquinolines with electron withdrawing substituents (ester and nitro) in the 3-position. Both the initial displacement of the 4-chloro-substituent and the cleavage of the 4-alkoxyquinoline is auto-catalyzed and takes place under neutral
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Published 13 Sep 2019

Friedel–Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts

  • Kenta Tanaka,
  • Yuta Tanaka,
  • Mami Kishimoto,
  • Yujiro Hoshino and
  • Kiyoshi Honda

Beilstein J. Org. Chem. 2019, 15, 2105–2112, doi:10.3762/bjoc.15.208

Graphical Abstract
  • addition, 2-methoxy and 2-trifluoromethyl-functionalized benzoyl chloride can be applied to the reaction (3c,d). The 4-methoxy group was also tolerated in the reaction (3e). Substrates with strong electron-withdrawing groups such as 4-trifluoromethyl, 4-nitro and 4-cyano groups reacted with moderate to
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Published 05 Sep 2019

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

  • Yulia V. Khoroshunova,
  • Denis A. Morozov,
  • Andrey I. Taratayko,
  • Polina D. Gladkikh,
  • Yuri I. Glazachev and
  • Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

Graphical Abstract
  • of nitroaldehyde 3c (25%). The reactive aldehyde groups were protected via 1,3-dioxolane assembly, and the resulting compounds were treated with Zn dust and NH4Cl in a water–THF solution to reduce nitro groups. The resulting hydroxylamines were treated with hydrochloric acid to hydrolyse dioxolane
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Published 27 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
  • aziridine esters 70 which were subjected to a selective reduction of the nitro group to afford the major pyrrolidine-2-one (2R,4'R,1''S)-71 after chromatographic purification [65]. The reduction of the amide bond gave (2R,3'R,1''S)-72 thus providing a cyclic part of (3S,3'R)-68. The transformation of the
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Published 23 Jul 2019

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)2A fluorescent dyes

  • Keiichi Imato,
  • Toshiaki Enoki,
  • Koji Uenaka and
  • Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

Graphical Abstract
  • an electron-donating group (D) such as a diphenyl or dialkylamino group and an electron-withdrawing group (electron-accepting group, A) such as a nitro, cyano, and carboxy group or an azine ring such as pyridine, pyrazine and triazine linked by π-conjugated bridges such as oligoenes and heterocycles
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Published 22 Jul 2019

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

  • Gagandeep Kour Reen,
  • Ashok Kumar and
  • Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Graphical Abstract
  • dimethylamino- or nitro-substituted aldehydes did not result in the target compound that might be due to the deactivation caused by coordination of these groups with the catalyst. Metal–carbene complexes attracted the attention of organic chemists and have become an important branch of organometallic chemistry
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Published 19 Jul 2019

Synthesis of 9-O-arylated berberines via copper-catalyzed CAr–O coupling reactions

  • Qiaoqiao Teng,
  • Xinhui Zhu,
  • Qianqian Guo,
  • Weihua Jiang,
  • Jiang Liu and
  • Qi Meng

Beilstein J. Org. Chem. 2019, 15, 1575–1580, doi:10.3762/bjoc.15.161

Graphical Abstract
  • elaborate motifs such as heterocycles [10][11][12], glucose [13], nitric oxide [14], and the multidrug-resistance pump inhibitor 5-nitro-2-phenylindole (INF55) [15] have been covalently attached to BBR, further widening its pharmacological spectrum. Aromatic rings are another family of substituents having
  • scope was investigated using various aryl iodides (Scheme 3). Both, electron-rich and electron-deficient aryl iodides afforded the corresponding 9-O-arylated tetrahydroberberines 2a–o in good to decent yields. Also, nitro and ester substituents were well-tolerated under these conditions giving the
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Published 15 Jul 2019

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

  • Aleksandr S. Krylov,
  • Artem A. Petrosian,
  • Julia L. Piterskaya,
  • Nataly I. Svintsitskaya and
  • Albina V. Dogadina

Beilstein J. Org. Chem. 2019, 15, 1563–1568, doi:10.3762/bjoc.15.159

Graphical Abstract
  • coupling constant of 2JНР ≈ 20 Hz. In the 13С NMR spectra, the methylene carbon resonated as a doublet at δ 23.5 ppm (JCP = 143 Hz). In addition, the structures of triazolopyridines 3–8 were unambiguously confirmed by the crystal structure of 5b. Remarkably, the presence of a nitro group in the pyridine
  • -type rearrangement, which is facilitated by the acceptor nitro group in the pyridine ring (Scheme 3) [17][18]. The reaction of 2-hydrazinyl-3-nitropyridine (1i) with dimethyl and diisopropyl chloroethynylphosphonates 2a and 2b proceeded selectively to furnish only [1,2,4]triazolo[1,5-a]pyridines 11
  • . The ease of the formation of isomers 11 in this case and 12 in other similar synthesis, is caused not only by the presence of a nitro group in the pyridine ring, but also by the presence of hydrogen chloride, which is eliminated by potassium carbonate in the former experiments (Scheme 2). The acid
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Published 12 Jul 2019

A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

  • András György Németh,
  • György Miklós Keserű and
  • Péter Ábrányi-Balogh

Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155

Graphical Abstract
  • -substituted product 3u. As the methoxy group is inert under the standard reaction conditions, one might assume that the electron-donating ability reduces the stability of the in situ-generated anion, just as in the case of the secondary and tertiary alcohols. The nitro derivative 3q was isolated in 30% yield
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Published 10 Jul 2019

Diazocine-functionalized TATA platforms

  • Roland Löw,
  • Talina Rusch,
  • Fynn Röhricht,
  • Olaf Magnussen and
  • Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

Graphical Abstract
  • bromotoluene 3 with TMS-protected acetylene 4 (95%). The C–C bond formation of 5 and 6 to give dibenzoyl 7 was achieved with potassium butoxide and elemental bromine (9%) according to a literature procedure [27]. The para-ethynyldiazocine 8 was obtained by reduction of both nitro groups, followed by oxidation
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Published 05 Jul 2019

One-pot activation–alkynylation–cyclization synthesis of 1,5-diacyl-5-hydroxypyrazolines in a consecutive three-component fashion

  • Christina Görgen,
  • Katharina Boden,
  • Guido J. Reiss,
  • Walter Frank and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 1360–1370, doi:10.3762/bjoc.15.136

Graphical Abstract
  • –15.2 μM (Figure 1) [23]. 1-Acyl-5-hydroxypyrazolines have been shown to be analgesics with a slightly improved pain-relieving efficacy than Aspirin® [24][25], and 5-nitro-2-furyl-substituted derivatives are active antibacterials against the strains S. aureus, A. aerogenes, E. coli and B. subtilis
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Published 19 Jun 2019

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

  • Alexander N. Reznikov,
  • Anastasiya E. Sibiryakova,
  • Marat R. Baimuratov,
  • Eugene V. Golovin,
  • Victor B. Rybakov and
  • Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

Graphical Abstract
  • nitroalkenes in the presence of Ni(II) complexes with various chiral vicinal diamines was studied. This reaction provides convenient access to non-racemic 4-nitro-2-sulfonylbutan-1-ones with two stereocenters with high yield and excellent enantioselectivity (up to 99%). It has been established that the
  • CO group of sulfone is placed on the side of the nitro group, whereas the bulkier sulfonyl group is oriented opposed to the nitro group to minimize steric interactions. Conclusion In summary, a convenient synthetic protocol for the preparation of valuable non-racemic 4-nitro-2-sulfonylbutan-1-ones
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Published 12 Jun 2019

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

  • Alexander F. de la Torre,
  • Gabriel S. Scatena,
  • Oscar Valdés,
  • Daniel G. Rivera and
  • Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

Graphical Abstract
  • , 1718, 1420, 1150, 1100, 800, 690, 600; microanalysis: N (0 %), C (56.14%), H (4.10%), S (0%); loading of catalyst = 0 mmol·g−1 (2R,3S)-2-Ethyl-4-nitro-3-phenylbutanal (5). Prepared by reaction of n-butanal with trans-β-nitrostyrene according to the general procedure C. The compound was purified by
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Published 04 Jun 2019

Synthesis of aryl cyclopropyl sulfides through copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid

  • Emeline Benoit,
  • Ahmed Fnaiche and
  • Alexandre Gagnon

Beilstein J. Org. Chem. 2019, 15, 1162–1171, doi:10.3762/bjoc.15.113

Graphical Abstract
  • was produced in a low 31% yield. Electron-withdrawing groups such as a fluorine, bromine, chlorine, trifluoromethyl and a nitro group as well as electron-donating groups such as a methoxy group at the para-position were found to be well tolerated, as indicated by aryl cyclopropyl sulfides 1h–m which
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Published 27 May 2019

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

  • Edorta Martínez de Marigorta,
  • Jesús M. de Los Santos,
  • Ana M. Ochoa de Retana,
  • Javier Vicario and
  • Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

Graphical Abstract
  • asymmetric products 131 is mainly obtained, where the aromatic group coming from the boronic acid partner settles far from the carbonyl group. Methoxy, nitro, chloro and acetoxy groups of the aromatic moiety can be located at the ortho, meta and para positions, although 2-nitro derivatives gave low yields or
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Published 08 May 2019

Photochemical generation of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical from caged nitroxides by near-infrared two-photon irradiation and its cytocidal effect on lung cancer cells

  • Ayato Yamada,
  • Manabu Abe,
  • Yoshinobu Nishimura,
  • Shoji Ishizaka,
  • Masashi Namba,
  • Taku Nakashima,
  • Kiyofumi Shimoji and
  • Noboru Hattori

Beilstein J. Org. Chem. 2019, 15, 863–873, doi:10.3762/bjoc.15.84

Graphical Abstract
  • (N-BARD), Hiroshima University. Preparation of caged compounds 2a and 2b 6-Ethyl-2-(4-nitrophenyl)benzofuran (5a). 4-Nitro-1-iodobenzene (16.3 g, 65.5 mmol), Pd(dppf)Cl2 (0.97 g, 1.3 mmol), PPh3 (recrystallized, 0.51 g, 1.9 mmol) and CuI (0.25 g, 1.3 mmol) were added under N2 atmosphere followed by
  • ), 109.47 (CH), 105.13 (CH), 83.28 (CH), 59.79 (C), 40.43 (CH2), 34.23 (CH3) , 23.82 (CH2), 20.40 (CH3), 17.24 (CH3); HRMS–ESI (m/z): [M + H]+ calcd. for C25H30N2O4, 423.22783; found, 423.22754. 5-Ethyl-2-(4-nitrophenyl)benzofuran (5b). 4-Nitro-1-iodobenzene (16.8 g, 67.5 mmol), Pd(dppf)Cl2 (1.0 g, 1.3 mmol
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Published 10 Apr 2019

An efficient and concise access to 2-amino-4H-benzothiopyran-4-one derivatives

  • Peng Li,
  • Yongqi Wu,
  • Tingting Zhang,
  • Chen Ma,
  • Ziyun Lin,
  • Gang Li and
  • Haihong Huang

Beilstein J. Org. Chem. 2019, 15, 703–709, doi:10.3762/bjoc.15.65

Graphical Abstract
  • -aminobenzothiopyranones containing 8-nitro and 6-trifluoromethyl substituents in low to moderate yields through the transformation of a 2-methylthio substituent under harsh conditions (method F, Scheme 1) [5]. In addition, the nucleophile imidazole could also react with 3-bromobenzothiopyranones to afford 2
  • , the 2-position of the benzopyranone scaffold is easier to be attacked by nucleophiles than that the corresponding benzothiopyranone. We anticipate that the electron-withdrawing effect of a cyano, carbonyl, nitro or trifluoromethyl group, especially at the 3-position could render the sulfide, sulfinyl
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Published 18 Mar 2019

Selective benzylic C–H monooxygenation mediated by iodine oxides

  • Kelsey B. LaMartina,
  • Haley K. Kuck,
  • Linda S. Oglesbee,
  • Asma Al-Odaini and
  • Nicholas C. Boaz

Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55

Graphical Abstract
  • , or methyl, respectively) slightly lowered the yield when compared to the parent NHPI-type catalyst (catalysts 2b,d). On the other hand, the use of the strongly electron-withdrawing 3-nitro-N-hydroxyphthalimide (2e) yielded no reaction, returning only starting material. The lack of iodine production
  • upon reaction with 2e as the catalyst suggests that the strongly electron withdrawing nitro substituent made the catalyst difficult to oxidize under the reaction conditions. While NHPI (2a) shows an E1/2 of 1.065 V the corresponding E1/2 of 3-nitro-N-hydroxyphthalimide (2e) is higher at 1.135 V versus
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Published 05 Mar 2019

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

  • Guillaume Ernouf,
  • Jean-Louis Brayer,
  • Christophe Meyer and
  • Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

Graphical Abstract
  • alkylidenecyclopropane 13i in nearly quantitative yield. Conversely, no rearrangement took place in the case of imidates 12e and 12g in which the aromatic group was substituted by a strongly electron-withdrawing nitro group at the para- or the meta-position, respectively. All these observations point toward the
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Published 05 Feb 2019

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

  • Patrycja Żak and
  • Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

Graphical Abstract
  • research, active in preliminary tests and commercially available second generation Grubbs–Hoveyda catalyst Ru-3 and its nitro derivative Ru-4 were selected. The same authors were able to successfully functionalize allylsilsesquioxane with more challenging, three different steroid derivatives. The reactions
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Published 04 Feb 2019
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