- Synthesis and characterization of 2,7-di(tertbutyl) pyreno[4,5-c:9,10- c′]difuran and derived pyrenophanes
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(Chemical Equation Presented) Isobenzofurans (IBF)s have seen widespread use in the synthesis of both natural products and polycyclic aromatic hydrocarbons. There are few examples that have two IBF entities linked in a fused aromatic ring system. Here we present the synthesis and characterization of a bis(IBF), 2,7-di(tert-butyl)pyreno[4,5-c:9,10-c0]difuran.Reactionwith bis(maleimide) dienophiles gives pyrenophanes. The solidstate structures of the bis(IBF) and two cyclophanes are discussed. 2009 American Chemical Society.
- Franz, David,Robbins, Steven J.,Boere, Rene T.,Dibble, Peter W.
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- Efficient solid-state emission and reversible mechanofluorochromism of a tetraphenylethene-pyrene-based β-diketonate boron complex
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A new twisted donor-acceptor (D-A) dye (BF2-TP) that was composed of tetraphenylethene and pyrene connected with a β-diketonate boron moiety has been synthesized and characterized. Such a dye showed unique intramolecular charge transfer (ICT) features, which were evidenced by spectral analysis and theoretical calculations. More importantly, BF2-TP solid samples exhibited an obvious mechanofluorochromic (MFC) behavior. Upon grinding with a spatula, the as-prepared powder sample illustrated a remarkable red shift of 62 nm, with considerable color contrast from yellow (562 nm) to orange red (624 nm). Its fluorescence color can be reversibly switched by repeating both the grinding-fuming and grinding-annealing processes. The mechanochromism is attributed to the phase transformation between amorphous and crystalline states. The results obtained would be helpful for designing novel MFC materials.
- Sun, Ting,Zhao, Feng,Xi, Gaolei,Gong, Jian,Sun, Mengyu,Dong, Chang,Qiu, Jingyi
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- HALOGENATION OF 2,7-DI-TERT-BUTYL-TRANS-10b,10c-DIALKYL-10b,10c-DIHYDROPYRENES
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Treatment of 2,7-di-tert-butyl-trans-10b,10c-dialkyl-10b,10c-dihydropyrenes 5a-5c with bromine afforded the corresponding tetrabromides 7a-7c in good yields, respectively.The tetrachloro derivative of 5a was also obtained in 40percent yield by the treatment of 5a with SO2Cl2.The bromination of 5a-5c with bromine in the presence of Fe powder gave the dealkylated compound 2,7-di-tert-4,5,9,10-tetrabromopyrene 8 in good yields, respectively.When 5a-5c were treated with I2, 2,7-di-tert-butylpyrene 9 was obtained in good yields, in all cases.
- Tashiro, Masashi,Yamato, Takehiko
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- 4,5,9,10-Pyrene Diimides: A Family of Aromatic Diimides Exhibiting High Electron Mobility and Two-Photon Excited Emission
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The design and synthesis of high-performance n-type organic semiconductors are important for the development of future organic optoelectronics. Facile synthetic routes to reach the K-region of pyrene and produce 4,5,9,10-pyrene diimide (PyDI) derivatives are reported. The PyDI derivatives exhibited efficient electron transport properties, with the highest electron mobility of up to 3.08 cm2 V?1 s?1. The tert-butyl-substituted compounds (t-PyDI) also showed good one- and two-photon excited fluorescence properties. The PyDI derivatives are a new family of aromatic diimides that may exhibit both high electron mobility and good light-emitting properties, thus making them excellent candidates for future optoelectronics.
- Wu, Ze-Hua,Huang, Zhuo-Ting,Guo, Rui-Xue,Sun, Chun-Lin,Chen, Li-Chuan,Sun, Bing,Shi, Zi-Fa,Shao, Xiangfeng,Li, Hanying,Zhang, Hao-Li
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- Nonvolatile organic field-effect transistor memory from pyrene-fused azaindacene regioisomers
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Nonvolatile memory devices based on organic materials are promising for a new generation of portable or flexible electronics. Herein, two pyrene-fused azaindacene configurational isomers, syn-B2IPIO and anti-B2IPIO, were designed and synthesized, and they are axially symmetric and centrally symmetric, respectively. These two regioisomers were applied as charge trapping elements (CTEs) for the electret layers in organic field-effect transistor nonvolatile memory (OFET-NVM) devices. Although the two regioisomers have nearly identical molecular structures, absorption spectra, and HOMO/LUMO energy levels, they exhibit distinctly different charge-trapping capabilities. The OFET-NVM devices based on anti-B2IPIO exhibit a moderate memory window of about 25 V. In contrast, the devices based on syn-B2IPIO show a more than two-fold wider memory window (~59 V). The different charge trapping behaviors of this pair of isomers are attributed to different intermolecular interactions associated with molecular symmetry, resulting in different molecular packing behaviors and film morphologies. The results reveal that controlling the molecular symmetry could be a new and efficient strategy for the design of organic CTEs for high-performance memory devices. This journal is
- Li, Xiang-Yang,Liu, Duan-Wu,Shao, Xiangfeng,Sun, Wen-Jing,Xiao, Qi,Zhang, Hao-Li,Zhang, Yamin
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- A novel thiophene-fused polycyclic aromatic with a tetracene core: Synthesis, characterization, optical and electrochemical properties
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FeCl3-mediated oxidative cyclization was successfully used to construct an extended thiophene-pendant pyrene skeleton and synthesize a novel thiophene-fused polycyclic aromatic (THTP-C) with a tetracene core. The identity of the compound was confirmed by 1H-NMR, 13C-NMR, MS, and elemental analysis. Meanwhile, a single crystal of THTP-C was obtained and analyzed by X-ray single-crystal diffraction. THTP-C has a "saddle" shaped π-conjugated 1-D supramolecular structure, and favors highly ordered self-assembly by π-π interactions as evidenced by its concentration- dependent 1H-NMR spectra in solution. The optical properties of THTP-C were investigated by ultraviolet-visible (UV-Vis) and photoluminescence (PL) spectroscopy and its electrochemical properties were investigated by cyclic voltammetry (CV). The relatively large band gap (2.86 eV), low EHOMO level (-5.64 eV) and intermolecular π-π interactions imply that THTP-C has a high stability against photo-degradation and oxidation, and may be a promising candidate for stable hole-transporting materials.
- Duan, Zong-Fan,Huang, Xian-Qiang,Yang, Zhi-Gang,Hoshino, Daiki,Kitanaka, Susumu,Zhao, Gao-Yang,Nishioka, Yasushiro
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- Triflic Acid-Promoted Adamantylation and tert-Butylation of Pyrene: Fluorescent Properties of Pyrene-Decorated Adamantanes and a Channeled Crystal Structure of 1,3,5-Tris(pyren-2-yl)adamantane
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Triflic acid-promoted 1-adamantylation and tert-butylation of pyrene at positions 2 and 2,7 along with the synthesis of compounds having one-, two-, and three-pyrenyl groups attached to the adamantane scaffold are disclosed. Fluorescent properties of these compounds and channeled crystal structure of the 1,3,5-tris(pyren-2-yl)adamantane containing chloroform as a guest are also presented.
- Wrona-Piotrowicz, Anna,Makal, Anna,Zakrzewski, Janusz
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- Blue-emitting pyrene-based aggregates
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The supramolecular polymerization of pyrene imidazoles 1 and 2, governed by H-bonding and C-H···π interactions, yields aggregates showing the characteristic bluish emission pattern of pyrene-based monomers.
- Valera, Jorge S.,Calbo, Joaquín,Gómez, Rafael,Ortí, Enrique,Sánchez, Luis
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- Modular Two-Step Access to π-Extended Naphthyridine Systems—Potent Building Blocks for Organic Electronics
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Efficient synthetic approaches for the incorporation of nitrogen into polyaromatic compounds (PACs) in different patterns as stabilising moiety for π-extended systems and modification tool for optoelectronic properties remain a challenge until today. Here
- Stuck, Fabian,Dietl, Martin C.,Mei?ner, Maximilian,Sebastian, Finn,Rudolph, Matthias,Rominger, Frank,Kr?mer, Petra,Hashmi, A. Stephen K.
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supporting information
(2021/12/14)
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- Relationship Between Molecular Structure, Single crystal Packing and Self-Assembly Behavior: A Case Based on Pyrene Imide Derivatives
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Development of new n-type one-dimensional (1D) self-assembly nanostructure and a clear understanding of the relationship between molecular structure and self-assembly behavior are important prerequisites for further designing and optimizing organic optoelectronic nanodevice. In this article, a series of n-type organic semiconductor materials based on pyrene imide were successfully synthesized through [4+2] cycloaddition reactions and their preliminary optical and electrochemical properties were studied. The simulated HOMO-LUMO bandgaps via DFT tallied with the experimental data well. The self-assembly of these materials showed needle or fiber-like morphologies, indicating that different conjugation degree or alkyl group had significant influence on their self-assembly behaviors. Furthermore, the single-crystal packing for these molecules were analyzed and it was found out that the changes of conjugated backbone and functional group would affect certain crystal lattice parameter significantly, such as the intermolecular packing distance and crystal size etc, which would further result in different self-assembly morphology.
- Li, Xiaojun,Zhang, Shilong,Chen, Wangqiao,Han, Hongjing,Qiu, Meizhen,Chen, Jiawen,Zhang, Qichun
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supporting information
(2021/12/08)
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- Synthesis of Distorted Nitrogen-Doped Nanographenes by Partially Oxidative Cyclodehydrogenation Reaction
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A series of partially fused N-doped nanographenes (2–4) are synthesized via the oxidative cyclodehydrogenation of oligoaryl-substituted dibenzo[e,l]pyrene (1), and five, six, and seven new C?C bonds are formed, respectively, implying stepwise C?C bond fusion and extended π-conjugation. Single-crystal X-ray diffraction analysis of compound 4 a revealed that the presence of sterically demanding groups hindered the formation of planar and fully fused nanographene in the oxidative cyclodehydrogenation reaction step. Optical study of compounds 2 to 4 showed that extended π-conjugation leads to a regular stepwise bathochromic shift in the absorption and emission spectra. Furthermore, the HOMO–LUMO gaps of these compounds exhibit a decrease as C?C bond formation proceeds. Thus, the optoelectronic properties of nanographenes are highly dependent on the formation of new C?C bonds in the molecular skeleton.
- Varghese, Eldhose V.,Gao, Chen-Feng,Chang, Yu-Lun,Chen, Hsing-Yin,Chen, Chia-Hsiang
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supporting information
(2022/02/23)
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- Synthesis and configurational character study of novel structural isomers based on pyrene-imidazole
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Isomers provide more possibilities for the structure of organic compounds. Molecular structures determine their corresponding properties, therefore the intrinsic relationship between structure and properties of isomers is of great research value. Isomers with a stable structure and excellent performance possess more potential for development and application. In this paper, we design and synthesize structural isomers with different molecular symmetries based on the asymmetric structure of imidazole and the symmetrical structure of pyrene. Isomers with stable molecular structures can be obtained by a simple and efficient “one-pot” reaction, involving axisymmetric configuration and centrosymmetric configuration. Using this “click-like” reaction, the structure of target molecules is controllable and adjustable. Furthermore, the effect of molecular configurations on molecular stacking of crystal is studied. The variation of the optical and thermal properties, the optimized structures, and orbital distributions of isomers depends on different molecular geometry with different symmetry, which are revealed by crystallographic analysis. This present strategy provides an efficient synthetic method for the design and synthesis of structural isomers based on pyrene-imidazole.
- Liu, Yu-Long,Yang, Liu,Guo, You-Quan,Xu, Guo-Qiang,Qu, Bin,Fu, Ying
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- A novel organic semiconductor material, preparation method, the field effect transistor device and manufacturing method thereof (by machine translation)
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A novel organic semiconductor material, preparation method, the field effect transistor device and manufacturing method thereof, relates to a photoelectric material field, as the basic framework by pi, using the same synthetic strategy, design, to synthesize a new kind of semiconductor material. Model of the semiconductor material in the form of a solid 365 nm ultraviolet light under different colors of emitted red light. By thermal vapor deposition and solution method to construct the field effect transistor device. The construction of the thin film field effect device exhibits a different electric charge transmission performance. (by machine translation)
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Paragraph 0098; 0101-0104
(2019/07/10)
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- Pyrene derivative, and preparation method and application thereof
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The invention relates to an organic micromolecular compound, and a preparation method and application of the compound. Specifically, the invention discloses a derivative containing pyrene and a preparation method, application of the derivative to semicond
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Paragraph 0022; 0023
(2016/11/17)
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- Solution-processable thiadiazoloquinoxaline-based donor-acceptor small molecules for thin-film transistors
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Although several [1,2,5]thiadiazolo[3,4-g]quinoxaline (TQ)-thiophene-based hybrid polymers have been demonstrated for application in organic field-effect transistors (OFETs), the research on the charge carrier mobility of conjugated donor (D)-acceptor (A) small molecules is rare. To enrich the TQ-containing small molecule family, in this paper, we designed and synthesized three novel TQ derivatives 1, 2, and 3 with thiophene units attached onto the TQ cores. The optoelectronic and OFET properties of as-prepared compounds 1-3 are investigated. Our results indicate that compounds 1-3 show typical p-type characteristics with mobility as high as 0.012, 0.05 and 0.0055 cm2 V-1 s-1 and on/off current ratios of 3 × 105, 1 × 106 and 1 × 104 under the optimized conditions, respectively. Due to the steric effect of the substituted bulky group, compound 3 adopts a looser packing mode with a larger π-π distance, which subsequently reduces the transport performance. Our results suggest that the D-A π-conjugated small molecules based on TQ could be good candidates for application in organic electronic devices.
- Gu, Pei-Yang,Zhang, Jing,Long, Guankui,Wang, Zilong,Zhang, Qichun
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supporting information
p. 3809 - 3814
(2016/05/19)
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- Synthesis and binding investigations of novel crown-ether derivatives of phenanthro[4,5- abc ]phenazine and quinoxalino[2′,3′:9,10] phenanthro[4,5- abc ]phenazine
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The synthesis and binding investigation of novel crown-ether derivatives of phenanthro[4,5-abc]phenazine and quinoxalino[2′,3′:9,10] phenanthro[4,5-abc]phenazine sensors are reported. The binding studies of these sensors with an array of alkali and alkaline-earth metals are exploited using UV-vis, fluorescence and nuclear magnetic resonance spectroscopies. 2013
- Jradi, Fadi M.,El-Ballouli, Ala'A O.,Al-Sayah, Mohammad H.,Kaafarani, Bilal R.
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- Synthesis, crystal structure and photophysical properties of pyrene-helicene hybrids
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Synthesis of helically chiral aromatics resulting from fusion of pyrene and [4]- or [5]helicene has been accomplished using photoredox catalysis employing a Cu-based sensitizer as the key step. Photocyclisation experiments for the synthesis of the target
- Bedard, Anne-Catherine,Vlassova, Anna,Hernandez-Perez, Augusto C.,Bessette, Andre,Hanan, Garry S.,Heuft, Matthew A.,Collins, Shawn K.
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supporting information
p. 16295 - 16302
(2013/12/04)
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- Ir-catalyzed direct borylation at the 4-position of pyrene
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The first direct borylation of a C-H bond at the 4-position of pyrene was achieved using [Ir(COD)Cl]2/dtbpy as the catalyst precursor and B2pin2 as the boron source. The position-related photophysical properties of pyrene
- Liu, Zhiqiang,Wang, Yuanyuan,Chen, Ying,Liu, Jie,Fang, Qi,Kleeberg, Christian,Marder, Todd B.
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scheme or table
p. 7124 - 7128
(2012/09/25)
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- Dicyanopyrazine-containing fused aromatic molecules: Potential n-type materials for use in optoelectronic devices
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Two dicyanopyrazine-containing aromatic compounds, pyrazino[2′, 3′:9,10]phenanthro[4,5-fgh]quinoxaline-5,6,12,13-tetracarbonitrile (PPQD) and pyrazino[2′,3′:9,10]phenanthro[4,5-fgh]quinoxaline-5,6,12,13- tetracarbonitrile,2,9-bis(1,1-dimethylethyl) (PPQB), which have remarkably high electron affinity and ionization potential, were synthesized and qualified as potential n-type materials for use in solar cells and organic light-emitting diodes.
- Li, Qing,Li, Jiuyan,Ren, Huicai,Gao, Zhanxian,Liu, Di
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experimental part
p. 3325 - 3333
(2011/09/19)
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- Facile synthesis and characterization of a novel thiophene-fused polycyclic aromatics based on pyrene
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A novel large thiophene-fused polycyclic aromatics 1 based on pyrene 5 has been synthesized, and its structure was confirmed by 1H NMR, 13C NMR, MS, UV-vis and elemental analysis. The key steps of the synthesis involved the Stille cross-coupling reaction and followed by selective β-β oxidative cyclization of pendant thienyl rings by FeCl3 under mild conditions.
- Duan, Zong Fan,Yang, Zhi Gang,Liu, Dong Jie,Cai, Li,Hoshino, Daiki,Morita, Tsuyoshi,Zhao, Gao Yang,Nishioka, Yasushiro
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scheme or table
p. 819 - 822
(2012/01/05)
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- A tetraalkylated pyrene building block for the synthesis of pyrene-fused azaacenes with enhanced solubility
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The synthesis and characterisation of a soluble pyrene-fused tetraazaoctacene derivative has been achieved by developing a key pyrene-based building block with four solubilising groups.
- Kulisic, Niksa,More, Sandeep,Mateo-Alonso, Aurelio
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scheme or table
p. 514 - 516
(2011/02/28)
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- Novel quinoxalinophenanthrophenazine-based molecules as sensors for anions: synthesis and binding investigations
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The design and synthesis of two novel quinoxalinophenanthrophenazine-based anion sensors are reported. Binding studies of these sensors with an array of mono- and polyatomic anions using UV-vis, fluorescence, and NMR titrations have shown 1:1 and 1:2 sens
- Raad, Farah S.,El-Ballouli, Ala'a O.,Moustafa, Rasha M.,Al-Sayah, Mohammad H.,Kaafarani, Bilal R.
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scheme or table
p. 2944 - 2952
(2010/06/16)
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- PYRENE COMPOUND AND ORGANIC LIGHT EMITTING DEVICE
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An object of the present invention is to provide a novel pyrene compound. Provided is a pyrene compound represented by the following general formula (I): wherein: R1 and R2 each represent a substituted or unsubstituted alkyl group; a
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Page/Page column 14-15
(2008/12/05)
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- Synthesis and metal-binding studies of a novel pyrene discotic
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The synthesis of a novel bis-crown quinoxalino[2′,3′:9,10]phenanthro[4,5-abc]phenazine discotic and its binding properties to a series of alkali and alkaline-earth metals is reported. A schematic representation of the binding equilibrium of the sensor to the metal is proposed. The binding constant of the sensor to barium(II) was estimated to be 1.4 × 104 M-1 based on 1H NMR studies.
- Jradi, Fadi M.,Al-Sayah, Mohammad H.,Kaafarani, Bilal R.
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p. 238 - 242
(2008/03/30)
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- DICARBOXYLIC ACIDS FOR DIELECTRICS WITH BARRIER EFFECT AGAINST COPPER DIFFUSION
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The invention relates to novel dicarboxylic acids of formula (I), where E and n have the meanings given in claim 1. The dicarboxylic acids are suitable for the production of polymers stable to high temperatures such as employed in microelectronics as a dielectric.
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Page/Page column 20-22
(2008/06/13)
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- Exceptionally persistent and oxygen-insensitive 2,7-di-tert-butylpyren-1- oxyl radical: Synthesis, dimerization, EPR and ENDOR spectra
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Oxidation of 2,7-di-tert-butyl-1-hydroxypyrene 1 yields the exceptionally persistent and oxygen-insensitive 2,7-di-tert-butylpyren-1-oxyl radical 2 whose EPR and ENDOR spectra give the following proton hyperfine coupling (hfc) constants: 0.526, 0.445, 0.426, 0.386, 0.157, 0.107, 0.088 and 0.0054 mT (g = 2.0037). The assignments of the protons are accomplished by measuring the EPR and ENDOR spectra of partly deuteriated 2,7-di-tert-butyl(4,5,9,10- 2H4)pyren-1-oxyl radical. Radical 2 is isolated as a dimer which is in equilibrium with 2 in solution, even at low temperatures. The thermodynamic parameters for the equilibrium are determined to be 7.2 ± 2.0 kJ mol-1 (ΔS) and - 35 ± 15 J mol-1 K-1 (ΔS), respectively. The very low ΔH and negative ΔS values are briefly discussed.
- Miura, Yozo,Yamano, Eiji,Miyazawa, Akira,Tashiro, Masashi
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p. 359 - 364
(2007/10/03)
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- Generation, Isolation, and Characterization of N-(Arylthio)-7-tert-butyl- and N-(Arylthio)-2,7-di-tert-butyl-1-pyrenylaminyl Radicals
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N-(Arylthio)-7-tert-butyl-1-pyrenylaminyl (2) and N--2,7-di-tert-butyl-1-pyrenylaminyl radicals (3) are prepared by PbO2 oxidation of N-(arylthio)-7-tert-butyl-1-aminopyrenes and N--2,7-di-tert-butyl-1-aminopyrene, respectively, and studied by ESR and ENDOR spectroscopy.The kinetic ESR study shows that, while aminyls 2 gradually decompose in solution at room temperature, aminyl 3 is quite persistent, even in refluxing benzene, and shows no tendency to dimerize, even at low temperatures.These interesting properties of 3 permit us to isolate 3 as radical crystals in 28-31percent yield.The hyperfine splitting (hfs) constants of 2 and 3, determined by ESR and ENDOR spectroscopic methods, show an extensive delocalization of the unpaired electron onto the pyrene ring.Comparison of the hfs constants of 2 and 3 shows that a more extensive delocalization of the spin into the pyrene ring takes place in 3.This is accounted for in terms of the difference in the conformations of 2 and 3.
- Miura, Yozo,Yamano, Eiji,Tanaka, Akio,Yamauchi, Jun
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p. 3294 - 3300
(2007/10/02)
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- Medium-Sized Cyclophanes, 29. Synthesis and Desulfurization of 2,11-Dithiametacyclo- and 2,11-Dithiaparacyclo(4,9)pyrenophanes
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2,11-Dithiametacyclo- (14b) and 2,11-dithiaparacyclo(4,9)pyrenophane (14c) were obtained by the coupling reactions of 4,9-bis(chloromethyl)pyrene (12) with the corresponding bis(mercaptomethyl)benzenes (13b,c).Attempted pyrolysis of the disulfones 18b, 18c to afford metacyclo- (19b) and paracyclo(4,9)pyrenophane (19c) failed.Only the ring cleavage products 16 and 20 were obtained.The sulfur dioxide extrusion by vapor-phase pyrolysis of the corresponding disulfone 18 to the highly strained 19 clearly demonstrates the limits of these preparative ring contraction method.The photolytic desulfurization of 14c afforded the (1,5)naphthalenoparacyclophane analogue 21 instead of paracyclo(4,9)pyrenophane 21'.The mechamism of the pyrolysis and photolysis reactions is discussed. - Key Words: Cyclophanes / Benzenopyrenophane, 4,9-bridged / Sulfones, pyrolysis of / Photodesulfurization / Naphthalenoparacyclophane, 1,5-bridged
- Yamato, Takehiko,Miyazawa, Akira,Tashiro, Masashi
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p. 2505 - 2512
(2007/10/02)
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- Friedel-Crafts alkylation of pyrene in carbon disulfide; 1H NMR spectroscopy of pyrene derivatives
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Friedel-Crafts alkylation of pyrene with 2,5-dichloro-2,5-dimethylhexane and 2,4-dichloro-2,4-dimethylpentane in carbon disulfide yields 7,7,10,10-tetramethyl-7,8,9,10-tetrahydrobenzopyrene and 7,7,9,9-tetramethyl-8,9-dihydro-7H-cyclopentapyrene, respectively, both in 99percent yield.Alkylation with 1,4-dichlorobutane, followed by aromatization, yields benzopyrene in a facile two-step synthesis in 8percent yield.A mechanism is proposed which rationalizes the fact that only one ring of pyrene undergoes substitution.The 1H-1H NMR coupling constants of the pyrene derivatives are discussed.
- Rodenburg, L.,Block, R. de,Erkelens, C.,Lugtenburg, J.,Cornelisse, J.
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p. 529 - 535
(2007/10/02)
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- Metacyclophanes and Related Compounds. 19. Reaction of 8-Methoxymetacyclophanes with Iodine in Benzene Solution. A Preparative Route of Pyrene
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When 8-methoxymetacyclophanes are treated with iodine in boiling benzene, the corresponding tetrahydropyrenes (8) are obtained in good yield.The AlCl3-catalyzed trans-tert-butylation of 8 effected loss of the tert-butyl group to give 10a-c, which were easily dehydrogenated with DDQ to afford the corresponding pyrene derivatives.
- Tashiro, Masashi,Yamato, Takehiko,Kobayashi, Kazumasa,Arimura, Takashi
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p. 3196 - 3199
(2007/10/02)
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- Synthesis and properties of nitro derivatives of 2-tert-butyl- and 2,7-di-tert-butylpyrene
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Nitration of 2-tert-butyl- and 2,7-di-tert-butylpyrene affords molecules with severely hindered nitro groups.A nitro group ortho to a tert-butyl group is twisted at least 82 deg out of the plane of the aromatic nucleus.The lack of interaction between the hindered nitro group and the aromatic system is reflected in the chemical behaviour, as well as in the spectroscopic properties, of these nitro derivatives. Upon fragmentation in the mass spectrometer, the tert-butyl group is always replaced by a hydrogen atom.Nitro groups are only replaced by a hydrogen atom if they are ortho to a tert-butyl group.
- Rodenburg, L.,Brandsma, R.,Tintel, C.,Thuijl, J. van,Lugtenburg, J.,Cornelisse, J.
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p. 156 - 161
(2007/10/02)
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- Metacyclophanes and Related Compounds. 14. Preparation of 8,16-Difluorometacyclophane
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Although preparation of 8,16-difluoro-, 8,16-dichloro-, and 8,16-dibromometacyclophanes was attempted, only 8,16-difluorometacyclophane was obtained from fluorobenzene in seven steps by using a tert-butyl group as a positional protective function.
- Tashiro, Masashi,Yamato, Takehiko
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p. 2939 - 2942
(2007/10/02)
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- Metacyclophanes and Related Compounds. 4. Halogenations of 8,16-Dialkyl-anti-5,13-di-tert-butylmetacyclophan-1-enes and 2,7-Di-tert-butyl-trans-10b,10c-dihydropyrenes
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8,16-Dialkyl-anti-5,13-di-tert-butylmetacyclophan-1-enes (13) and 2,7-di-tert-butyl-trans-10b,10c-dialkyl10b,10c-dihydropyrenes (20 a-c) wereprepared from the corresponding alkylbenzenes in several steps.The bromination of 13 and 20 with bromine in a carbon tetrachloride solution afforded 2,7-di-tert-butyl-4,5,9,10-tetrabromo-trans-10b,10c-dialkyl-10b,10c-dihydropyrenes (2).Treatment of 20 with iodine in a boiling benzene solution gave the dealkylated compound, 2,7-di-tert-butylpyrene (28).Such dealkylation was also observed in the bromination of 20 with bromine in the presence of Fe powder.However, without Fe powder, the bromination of 20 did not give any products.It was also found that the chlorination of 13a and 20a with iodine chloride of chlorine afforded the further chlorinated 2,7-di-tert-butyl-2,4,5,9,10-hexachloro-trans-10b,10c-dimethyl-2,7,10b,10c-tetrahydropyrene (30).The reaction pathways of the halogenation of the titled compounds are also discussed.
- Tashiro, Masashi,Yamato, Takehiko
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p. 3701 - 3707
(2007/10/02)
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