17402-80-1Relevant academic research and scientific papers
A new synthesis of pyrroles and porphyrins fused with aromatic rings
Ono, Noboru,Hironaga, Hideo,Ono, Kazuo,Kaneko, Syunichi,Murashima, Takashi,Ueda, Takahiro,Tsukamura, Chikanori,Ogawa, Takuji
, p. 417 - 423 (1996)
Pyrroles fused with aromatic rings (isoindole derivatives) have been readily prepared by the reaction of aromatic nitro compounds with ethyl isocyanoacetate in the presence of DBU. The ease of this reaction depends on the aromaticity of the starting nitro aromatics. Polycyclic aromatic nitro compounds such as 1-nitroacenaphthylene or 9-nitrophenanthrene are more reactive than simple nitro aromatics such as nitrobenzene or nitronaphthalenes and give the corresponding pyrroles in good yields. Pyrroles prepared by this method have been converted into porphyrins fused with various aromatic rings by the reduction with LiAlH4 followed by treatment with an acid catalyst and oxidation with chloranil or oxygen. Tetra-1,2-naphthoporphyrin has been prepared by the reaction of 2-nitro-3,4-dihydronaphthalene or 1-nitronaphthalene with ethyl isocyanoacetate followed by reduction, tetramerization and oxidation. Thus, highly conjugated porphyrins are readily prepared starting from aromatic nitro compounds, and their electronic and optical properties can be controlled by choice of the starting aromatic nitro compound.
A novel approach to the evaluation of the importance of steric and electronic effects in SNAr reactions: A computational, thermodynamic and 1H and 13C NMR study of meisenheimer-type adducts in the benzo[b]thiophene series
Consiglio, Giovanni,Cosimelli, Barbara,Guernelli, Susanna,Lanza, Camilla Zaira,Sancassan, Fernando,Spinelli, Domenico,Stenta, Marco
, p. 5807 - 5816 (2010)
The synthetically useful nucleophilic attack on nitrobenzo[b]thiophenes, a starting point for ring-opening/ring-closure pathways to different heterocyclic systems, has been investigated in detail. 3-Nitrobenzo[b]thiophene (9) and 2-nitrobenzo[b]thiophene (10) react with sodium methoxide in either DMSO or methanol to give the relevant Meisenheimer-type adducts 9′ and 10′, identified by NMR spectroscopy. A UV study indicated that the equilibrium constants for the formation of 9′ at 293 K are 10.1 and 40700 Lmol-1 in methanol and in DMSO, respectively. Competition reactions showed that the stability constant of 10′ is lower than that of 9′: accordingly, DFT [B3LYP/6-31+G(d,p)] calculations indicate that the formation of 9′ is thermodynamically more favoured than that of 10′ both in the gas phase and in DMSO. The reason for the opposite sequence in the stability constants previously found for the corresponding gem-dimethoxy Meisenheimer adducts 7′ and 8′ was therefore investigated in depth and appears to be a consequence of different steric interactions in the starting compounds, 2-methoxy-3-nitro-(7) and 3-methoxy-2-nitrobenzo[b]thiophene (8), respectively. A study of 13C NMR chemical shift changes accompanying the formation of adducts 9′ and 10′ confirms that the formation of the adduct exhibiting the larger stability constant is accompanied by a smaller π electron density redistribution, as we have previously found in other cases all governed by electronic effects. The opposite behaviour is observed in the formation of the gem-dimethoxy adducts 7′ and 8′, which is a consequence of the predominance of steric effects. Further outcomes of more general interest deal with the aromatic character of benzo[b]thiophenes. NMR spectroscopic data and calculated bond lengths show that in the studied reactions the benzene ring, unlike the thiophene one, is scarcely affected by methoxide addition, retaining its nearly full aromatic character. Benzocondensation increases the stability constants of σ-adducts mainly because of a marked reduction in the aromatic character of the thiophene ring in the substrates. 13C NMR chemical shifts can contribute to evaluations of whether or not steric effects are important in SNAr reactions. Provided that electronic effects prevail, Meisenheimer-type adducts at the C atom in α position to S also exhibit the larger stability constants when the thiophene ring is benzo[b]-fused. Benzo[b]-condensation causes a dramatic decrease in the aromatic character of the thiophene ring.
Silver-Catalyzed Asymmetric Dearomatization of Electron-Deficient Heteroarenes via Interrupted Barton–Zard Reaction
Wan, Qian,Xie, Jia-Hao,You, Shu-Li,Yuan, Yao-Feng,Zheng, Chao
supporting information, p. 19730 - 19734 (2021/08/03)
Herein we report a catalytic asymmetric dearomatization reaction of electron-deficient heteroarenes with α-substituted isocyanoacetates through an interrupted Barton–Zard reaction. A range of optically active pyrrolo[3,4-b]indole derivatives was obtained
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.
Palladium-Catalyzed Highly Stereoselective Dearomative [3 + 2] Cycloaddition of Nitrobenzofurans
Cheng, Qiang,Zhang, Hui-Jun,Yue, Wen-Jun,You, Shu-Li
supporting information, p. 428 - 436 (2017/09/22)
Stereoselective construction of highly functionalized heterocyclic molecules is an ongoing concern for the chemical community. Among the various strategies developed with this goal, catalytic asymmetric dearomatization, an attractive method for constucting cyclic molecules with multiple stereocenters from readily available aromatic compounds, has received extensive attention in recent years. Here, we report a highly stereoselective construction of tetrahydrofurobenzofurans and tetrahydrofurobenzothiophenes via palladium-catalyzed dearomative [3 + 2] cycloaddition of nitrobenzofurans and nitrobenzothiophenes, respectively. Good to excellent yields (63%–92%), diastereoselectivity (13/1 → >20/1 dr), and enantioselectivity (75%–95% ee) were obtained, leading to products with vicinal stereogenic carbon centers. The reaction features wide substrate scope and diverse transformations of the products.
Compd., marking agent, a solar cell module, solar power generation device, an organic thin film solar cell, and organic EL element display device (by machine translation)
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Paragraph 0419-0423, (2016/10/20)
PROBLEM TO BE SOLVED: sufficiently long wavelength emission wavelength is sufficiently high luminous efficiency and a new compound, and the compound and a marking agent. SOLUTION: compound represented by eq. (1). The marking agent comprising; a light inci
A mild and efficient method for the mononitration of aromatic compounds by cerium (III) ammonium nitrate in acetic anhydride
Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Satsumabayashi, Koko,Horaguchi, Takaaki
, p. 497 - 499 (2007/10/03)
A mild and efficient method for the mononitration of aromatic and olefinic compounds is described. This method is especially useful for active substrates.
