15241-23-3Relevant academic research and scientific papers
On the Steric Course of the Reaction of Enamines Derived from Open-Chain Aldehydes and Ketones with Nitro-olefins Yielding 2,3-Disubstituted 4-Nitroketones
Seebach, Dieter,Beck, Albert K.,Golinski, Jerzy,Hay, John N.,Laube, Thomas
, p. 162 - 172 (1985)
The relative configuration of the nitro-ketone 12 obtained by the title reaction has been proved by a Baeyer-Villiger degradation and subsequent reduction to the amino-alcohol (+/-)-(u)-20, the relative configuration of which is identical with a sample prepared from 2-methyl-3-hydroxybutyrate of known configuration (Scheme 1).The stereochemical course of the title reaction is thus as predicted by our topological rule.It is assumed that the other nitro-ketones 13-18 described here are also formed by (lk)-combination of the trigonal centers of the educts (diastereoselectivity > 90percent, see Formulae and Fig. 1).It is not possible to reverse this relative topicity by employing (Z)-instead of (E)-components of the starting materials, due to the reversibility of the primary step of these Michael additions (Schemes 2 and 3, and Fig.2).
Mono- and biphotonic photochemistry in glass matrices
Kaupp, Gerd
, p. 140 - 156 (2006)
Photochemistry in hard glassy solvent matrices gives different results than in gas matrices. It is performed at 83, 77, and ≥10 K by continuous irradiation and by pulsed multi MW cm-2 peak intensity excitation for those systems that do not react monophotonically. The highly structured matrix spectra should be taken as a basis for the interpretation of transient spectra to avoid ambiguities. Numerous [2.2]paracyclophanes are photolyzed. Most of them give stable diradical and quinodimethane spectra in addition to fluorescence and phosphorescence. Some benzylic diradicals undergo chemiluminescence after their photochemical generation. Matrix isolation spectroscopy is at variance with common interpretations in the lepidopterene case. A [2+4]-photocycloreversion of a substituted cyclohexene at 83 K leads to diene stereoisomers/rotamers that isomerize upon further irradiation. E/Z-photoequilibria are obtained in MTHF matrix from both sides with ω-nitrostyrene and α-benzylidene-γ-butyrolactone at 83 K, the latter stereoisomerization was also successfully studied at 10 K. Pulsed irradiation of technical photostabilizers at 10 K leads to stable zwitterion formation by proton migration that cannot be seen by continuous excitation. Inter- and intramolecular donor acceptor systems provide stable charge separation at 15 or 77 K upon pulsed laser irradiation and radicalanion spectra are recorded. Biphotonic photochemistry at ≥10 K allows for the formation of new ring systems such as dioxathiirane (cyclo-SO2), several aryldioxaziridines, and an electron rich triaziridine, compounds that revert upon thawing and could not be obtained by continuous irradiation, except cyclo-SO2 that can also be formed after absorption of the long lived SO2 triplet by another two-photon process.
Visible light-mediated intermolecular [2 + 2] photocycloaddition of 1-aryl-2-nitroethenes and olefins
Mohr, Lisa-Marie,Bauer, Andreas,Jandl, Christian,Bach, Thorsten
supporting information, p. 7192 - 7203 (2019/08/07)
Despite the importance of cyclobutanes there are not many direct [2 + 2] photocycloaddition reactions which can be performed with visible light in the absence of a catalyst. A notable exception is the reaction of 1-aryl-2-nitroethenes and olefins which can be performed at a wavelength of λ = 419 nm or λ = 424 nm in CH2Cl2 as the solvent. In the present study, a total of 15 1-aryl-2-nitroethenes were found to undergo a [2 + 2] photocycloaddition with 2,3-dimethyl-2-butene (28-86% yield) and a set of 12 olefins was studied in their photocycloaddition to 1-phenyl-2-nitroethene (37-88% yield). All mechanistic results are in agreement with a triplet reaction pathway and with the intermediacy of a 1,4-diradical.
Synthetic Diversity from a Versatile and Radical Nitrating Reagent
Zhang, Kun,Jelier, Benson,Passera, Alessandro,Jeschke, Gunnar,Katayev, Dmitry
supporting information, p. 12929 - 12939 (2019/09/17)
We leverage the slow liberation of nitrogen dioxide from a newly discovered, inexpensive succinimide-derived reagent to allow for the C?H diversification of alkenes and alkynes. Beyond furnishing a library of aryl β-nitroalkenes, this reagent provides unparalleled access to β-nitrohydrins and β-nitroethers. Detailed mechanistic studies strongly suggest that a mesolytic N?N bond fragmentation liberates a nitryl radical. Using in situ photo-sensitized, electron paramagnetic resonance spectroscopy, we observed direct evidence of a nitryl radical in solution by nitrone spin-trapping. To further exhibit versatility of N-nitrosuccinimide under photoredox conditions, the late-stage diversification of an extensive number of C?H partners to prepare isoxazolines and isoxazoles is presented. This approach allows for the formation of an in situ nitrile oxide from a ketone partner, the presence of which is detected by the formation of the corresponding furoxan when conducted in the absence of a dipolarophile. This 1,3-dipolar cycloaddition with nitrile oxides and alkenes or alkynes proceeds in a single-operational step using a mild, regioselective, and general protocol with broad chemoselectivity.
Light-Enabled Enantiodivergence: Stereospecific Reduction of Activated Alkenes Using a Single Organocatalyst Enantiomer
Hostmann, Theresa,Molloy, John J.,Bussmann, Kathrin,Gilmour, Ryan
supporting information, p. 10164 - 10168 (2019/12/24)
Light-enabled enantiodivergence is demonstrated in which the alkene substrate configuration is manipulated (E → Z) prior to organocatalytic reduction with a chiral thiourea and Hantzsch ester. This allows stereodivergent reduction to be regulated at the substrate level with high fidelity and mitigates the need for a second, enantiomeric catalyst (up to 93:07 and 95:5 er). The synthetic utility of this strategy has been demonstrated in the synthesis of the weight-loss drug (R)-Lorcaserin (Belviq) and a potent AMPA modulator.
Inhibition of LDL oxidation and inflammasome assembly by nitroaliphatic derivatives. Potential use as anti-inflammatory and anti-atherogenic agents
Cataldo, Nicolás,Musetti, Bruno,Celano, Laura,Carabio, Claudio,Cassina, Adriana,Cerecetto, Hugo,González, Mercedes,Thomson, Leonor
, p. 178 - 186 (2018/10/15)
We have previously shown the antioxidant and anti-inflammatory properties of several para-substituted arylnitroalkenes. Since oxidative stress and inflammation are key processes that drive the initiation and progression of atherosclerosis, in the present work the antioxidant, anti-inflammatory and anti-atherogenic properties of an extended library of aryl-nitroaliphatic derivatives, including several newly designed nitroalkanes, was explored. The antioxidant capacity of the nitroaliphatic compounds, measured using the oxygen radical absorbance capacity assay (ORAC) showed that the p-methylthiophenyl-derivatives were about three times more effective than Trolox to prevent fluorescein oxidation, independently of the presence or the absence of the double bond next to the nitro group. The peroxyl radical scavenger capacity of the p-dimethylaminophenyl-derivatives was even higher, being the reduced form of these compounds even more active. In fact, while the antioxidant capacity of 1-dimethylamino-4-(2-nitro-1Z-ethenyl)benzene and 1-dimethylamino-4-(2-nitro-1Z-propenyl)benzene was 4.2 ± 0.1 and 5.4 ± 0.1 Trolox Eq/mol, respectively; ORAC values obtained with the ethyl and the propyl derivatives were 10 ± 1 and 13 ± 2 Trolox Eq/mol, respectively. The p-dimethylamino-derivatives, especially the nitroalkanes, were also able to prevent LDL oxidation mediated by peroxyl radicals. Oxygen consumption due to the oxidation of fatty acids was delayed in the presence of the dimethylamino substituted compounds, only the alkanes interrupted the chain of lipid oxidations decreasing the rate of oxygen consumption. Although the formation of foam cells in the presence of oxidized-LDL (oxLDL) remained unaffected, the molecules containing the dimethylamino moiety were able to decrease the expression of IL-1β in LPS/INF-γ challenged macrophages.
Direct aziridination of nitroalkenes affording N-alkyl-C-nitroaziridines and the subsequent Lewis acid mediated isomerization to β-nitroenamines
Hao, Feiyue,Asahara, Haruyasu,Nishiwaki, Nagatoshi
supporting information, p. 5442 - 5445 (2017/11/06)
A mild and highly diastereoselective one-pot synthesis of trans-N-alkyl-C-nitroaziridines was achieved by treatment of nitroalkenes with aliphatic amines and N-chlorosuccinimide. Treatment of the obtained aziridines with a Lewis acid resulted in a facile ring opening reaction, accompanied by rearrangement and isomerization into functionalized (Z)-β-nitroenamines.
Intermolecular [2+2] Photocycloaddition of β-Nitrostyrenes to Olefins upon Irradiation with Visible Light
Mohr, Lisa-Marie,Bach, Thorsten
, p. 2946 - 2950 (2017/12/14)
The title compounds were found to undergo a [2+2] photocycloaddition with olefins at λ = 419 nm in CH 2 Cl 2 as the solvent. The resulting cyclobutanes were isolated in yields of 32-87% (11 examples) and showed a defined relative configuration at C1/C4 in the major diastereoisomer (nitro and aryl trans). The analysis of side products and triplet sensitization experiments support a mechanistic scenario in which a 1,4-diradical is formed as a key intermediate.
Arylnitroalkenes as scavengers of macrophage-generated oxidants
Celano, Laura,Carabio, Claudio,Frache, Renata,Cataldo, Nicolás,Cerecetto, Hugo,González, Mercedes,Thomson, Leonor
, p. 31 - 40 (2014/02/14)
Oxygen and nitrogen derived molecules mediated oxidation and nitration have been involved in several pathological conditions. Conversely, nitric oxide and hydrogen peroxide are important signalization intermediates, whose concentrations are tightly regula
A selective and practical synthesis of nitroolefins
Jovel, Irina,Prateeptongkum, Saisuree,Jackstell, Ralf,Vogl, Nadine,Weckbecker, Christoph,Beller, Matthias
experimental part, p. 2493 - 2497 (2009/08/14)
A straightforward and general synthesis of nitroolefins from nitric oxide (NO) and olefins is presented. The direct nitration of aromatic olefins, allyl compounds, and acrylic acid derivatives proceeds smoothly at room temperature with high regioselectivity and good yields. The advantages of this novel procedure compared to established nitration procedures are demonstrated.
