- Organic nanocrystals of [2.2]paracyclophanes achieved via sonochemistry: Enhanced and red-shifted emission involving edge-to-face chromophores
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We have prepared organic nanocrystals of [2.2]paracyclophane (pCp) and tetrakis(4-pyridylcyclobutyl)[2.2]paracyclophane (tpcp) via sonochemistry. Both nanocrystals exhibit an enhanced fluorescence compared to dilute solution, while the tpcp nanocrystals also demonstrate a red-shifted fluorescence.
- Elacqua, Elizabeth,Jurgens, Paul T.,Baltrusaitis, Jonas,MacGillivray, Leonard R.
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- SYNTHESIS OF CYCLOPHANES BY PHOTODESELENATIVE RINGCONTRACTION
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Several cyclophanes were prepared by photodeselenation of diselenacyclophanes with hexamethylphosphorous triamide in excellent yields, compared with the other chalcogen-atom extrusion methods.
- Higuchi, Hiroyuki,Kugimiya, Masao,Otsubo, Tetsuo,Sakata, Yoshiteru,Misumi, Soichi
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- Laser flash photolysis of [3,n]paracyclophan-2-ones. Direct observation and chemical behavior of 4,4′-(1,n-alkanediyl)bisbenzyl biradicals
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The 4,4′-(1,n-alkanediyl)bisbenzyl biradicals (2b-d) have been generated from the Norrish type-I reaction of [3,n]paracyclophan-2-ones (1b-d) giving the paracyclophanes 3b-d as the only reaction products. The behavior of biradicals 2b-d has been studied in detail and compared with the previously reported biradical 2a. The lifetimes increase as the chain length decreases and are affected by the solvent viscosity, thus showing the effect of the length of the chain on the conformations of the biradicals. Quenching with persistent radicals such as TEMPO resulted in length-dependent rate constants. Finally, the study of the magnetic field effects on the biradical lifetimes suggest that ISC control determines biradical lifetimes for long-chain systems.
- Font-Sanchis, Enrique,Miranda, Miguel A.,Perez-Prieto, Julia,Scaiano
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- A NEW SYNTHETIC METHOD OF CYCLOPHANES
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Diazacyclophanes were converted to the correspondingcyclophanes via their N-nitroso derivatives by reductive extrusion of nitrogens.This reaction is simple, clean and mild, and may be an alternative synthetic way of cyclophanes.
- Takemura, Hiroyuki,Shinmyozu, Teruo,Inazu, Takahiko
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- A new synthetic method of [2.2]cyclopbanes from [3.3]cyclophane-2,11- diones via photodecarbonylation
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Photoirradiation of [3,3]cyclophane-2,11-diones with a high-pressure Hg lamp in benzene provides the corresponding [2,2]cyclophanes in high yields along with [3,2]-cyclophane-2-ones.
- Isaji, Hajime,Sako, Katsuya,Takemura, Hiroyuki,Tatemitsu, Hitoshi,Shinmyozu, Teruo
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- A NEW AND FACILE ROUTE FROM A THIAPHANE TO A CYCLOPHANE VIA IRON PENTACARBONYL
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2,11-Dithiaparacyclophane is converted into -paracyclophane in 62percent yield by treatment with Fe(CO)5 in refluxing toluene.
- Koray, Ali R.
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- The 4,4′-(1,2-ethanediyl)bisbenzyl biradical: Its generation, detection, and (photo)chemical behavior in solution
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The 4,4′-(1,2-ethanediyl)bisbenzyl biradical (2) is clearly and efficiently generated by photolysis of [3.2]paracyclophane-2-one (8) in cyclohexane solution. This intermediate is also formed via two-photon processes from [2.2]paracyclophane (3) and 1,2-bi
- Miranda,Font-Sanchis,Perez-Prieto,Scaiano
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Read Online
- Preparation method of parylene
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The invention discloses a preparation method of parylene. The method comprises the steps: carrying out a reaction on a compound 1A to obtain a compound 2A; and reacting the compound 2A with a compound2B to obtain a parylene crude product, and purifying the parylene crude product to obtain a parylene fine product. According to the method, the reagent with lower price is used as a starting raw material, the final product is obtained through two-step reaction, the reaction condition of each step is mild, the yield of the obtained parylene is high, and the cost can be greatly reduced.
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Paragraph 0046-0048; 0051-0052
(2021/04/03)
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- The synthesis of a [2.2]paracyclophane-derived secondary phosphine oxide and a study of its reactivity
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A planar chiral secondary phosphine oxide based on [2.2]paracyclophane was synthesized and its chemistry investigated; it was shown to be a competent pre-ligand in palladium(0)-mediated reactions, and displayed promising activity in gold(I)-catalysed cyclisations. The secondary phosphine oxide could be transformed into a collection of P-stereogenic tertiary phosphine oxides. These are rare examples of the planar chirality of [2.2]paracyclophane being combined with a P-stereogenic centre. Unfortunately, epimerisation of the phosphorus stereocentre during reduction limits the use of this chemistry.
- Mungalpara, Maulik N.,Wang, Jingjing,Coles, Martyn P.,Plieger, Paul G.,Rowlands, Gareth J.
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p. 5519 - 5527
(2018/05/26)
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- A resolution method for 4-amino-12-bromo[2.2]paracyclophane
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A resolution method for 4-amino-12-bromo[2.2]paracyclophane is provided. L-proline protected by t-butyloxycarbonyl and racemic 4-amino-12-bromo[2.2]paracyclophane are reacted to generate a mixture of intermediates having configurations of (Rp, S) and (Sp, S). By utilizing a physical property difference (polar difference) of the intermediates having configurations of (Rp, S) and (Sp, S), the intermediates are separated by utilizing column chromatography, then recrystallization is performed for purification, and acidolysis is performed to obtain optically pure Sp-4-amino-12-bromo[2.2]paracyclophane and Rp-4-amino-12-bromo[2.2]paracyclophane. A resolution agent used in the method is cheap and nontoxic, resolution operation steps are simple, and high yields and good optical purities can be achieved, so that the method is suitable for large-scale preparation of the optically pure 4-amino-12-bromo[2.2]paracyclophane.
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Paragraph 0052; 0054
(2017/09/26)
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- Method for using microchannel reactor to prepare paracyclophane monomeric compound
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The invention discloses a method for using a microchannel reactor to prepare a paracyclophane monomeric compound. The method comprises the steps of preheating, intermediate synthesizing, product synthesizing, oil-water separating, purifying and the like. The paracyclophane monomeric compound is prepared in the continuous microchannel reactor. The method for using the microchannel reactor to prepare the paracyclophane monomeric compound has the advantages of being low in cost and small in energy consumption, having less three wastes, having continuous controllability, having no amplification effect and the like, and is capable of being subjected to simple amplification with equal ratio according to a demand of practical production.
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Paragraph 0046; 0050-0053
(2017/08/23)
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- The synthesis of planar chiral pseudo-gem aminophosphine pre-ligands based on [2.2]paracyclophane
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The synthesis of three planar chiral pseudo-gem disubstituted [2.2]paracyclophane-derived P,N-pre-ligands is reported along with preliminary results of their activity in the amination of aryl bromides and chlorides. The pseudo-gem aminophosphines were capable of mediating the coupling reaction at a loading of 1 mol%.
- Jayasundera, Krishanthi P.,Engels, Tim G. W.,Lun, David J.,Mungalpara, Maulik N.,Plieger, Paul G.,Rowlands, Gareth J.
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p. 8975 - 8984
(2017/11/09)
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- A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane
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We report a green and convenient protocol to prepare 4,7,12,15-tetrachloro[2.2]paracyclophane, the precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2-HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination-dimerization step, using aqueous sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way.
- Pan, Donghui,Wang, Yanbin,Xiao, Guomin
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p. 2443 - 2449
(2016/12/07)
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- Preparation method of cyclic di-p-xylyene
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The invention discloses a preparation method of cyclic di-p-xylyen. The method mainly includes the steps of: taking p-xylene as the starting raw material, performing bromination to obtain p-methylbenzyl bromide, and then carrying out reaction with triethylamine to obtain a corresponding quaternary ammonium salt, and finally adding the quaternary ammonium salt into a system containing a mixed solvent, alkali liquor and a mixed catalyst dropwise, and carrying out reaction for certain period of time to obtain cyclic di-p-xylyene, and finally performing aftertreatment to obtain a cyclic di-p-xylyene pure product. The method provided by the invention has the advantages of cheap and easily available raw materials, short reaction time, strong continuity, high yield, high purity and small solvent consumption, etc., and can be used for large-scale production.
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Paragraph 0038; 0039
(2016/10/07)
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- Formation of [2,2]Paracyclophane and Related Compounds and Methods for the Formation of Polymers from Cyclophanes
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An improved process and method for the formation of stable intermediate cyclophanes. Embodiments describe a general method for the production of substituted and unsubstituted cyclophanes. The components include a pyrolysis reaction tube that may be electrically heated into which a flowing stream of nitrous oxide with xylene vapor in an optional inert carrier gas at atmospheric pressure. The exit gas is condensed resulting in the deposition of [2,2′]paracyclophane. Additionally a process and method whereby the reactive intermediates of the reaction described above can be directly deposited and polymerized at atmospheric pressures or thereabout is disclosed.
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Page/Page column 3
(2013/05/09)
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- Mild preparation of functionalized [2.2]paracyclophanes via the Pummerer rearrangement
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[2.2]Paracyclophanes, incorporating functional groups in the aliphatic bridges, suitable for elimination to give [2.2]paracyclophanedienes, are synthesized through a novel approach. It relies on a double Pummerer rearrangement on dithiacyclophane precursors, followed by ring contraction through a photochemical sulfur extrusion, and it is compatible with aryl moieties possessing very different electronic properties. The Royal Society of Chemistry 2011.
- Montanari, Matteo,Bugana, Alberto,Sharma, Arvind K.,Pasini, Dario
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supporting information; experimental part
p. 5018 - 5020
(2011/09/14)
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- Towards a flexible strategy for the synthesis of enantiomerically pure [2.2]paracyclophane derivatives: The chemistry of 4-tolylsulfinyl[2.2] paracyclophane
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The use of enantiomerically enriched 4-tolylsulfinyl[2.2]paracyclophane as a precursor to a variety of mono- and di-substituted [2.2]paracyclophane derivatives is described. The goal of our research is to develop a single general precursor that permits the synthesis of the most common [2.2]paracyclophane substitution patterns. The chemistry of two diastereoisomers of 4-tolylsulfinyl[2.2]paracyclophane has been explored and it facilitates the synthesis of enantiomerically enriched 4-substituted and 4,13-disubstituted [2.2]paracyclophanes. Directed lithiations result in an unusual cyclisation reaction. Whilst the tolyl group cannot realise our goal, the chemistry outlined acts as a successful proof of concept.
- Parmar, Rakesh,Coles, Martyn P.,Hitchcock, Peter B.,Rowlands, Gareth J.
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experimental part
p. 4177 - 4187
(2011/02/25)
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- Symmetrically tetrasubstituted [2.2]paracyclophanes: Their systematization and regioselective synthesis of several types of bis-bifunctional derivatives by double electrophilic substitution
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The possible number of chiral and achiral tetrasubstituted [2.2]paracyclophanes possessing different types of symmetry (C2, Ci, Cs, C2., C2h) is evaluated and a unified independent trivial naming descriptor system is introduced. The reactivity and regioselectivity of the electrophilic substitution of the chiral pseudo-mefaand achiral pseudo-para-disubstituted [2.2]paracyclophanes are investigated in an approach suggested to be general for the synthesis of bis-bifunctional [2.2]paracyclophanes. The mono- and diacylation of chiral pseudo-meta-dihydroxy[2.2]paracyclophane 14 with acetylchloride occur ortho-regioselectively to produce tri- 22, 23 and symmetrically 21 tetrasubstituted acyl derivatives. The same reaction with benzoylchloride is neither regio-, nor chemoselective, and gives rise to a mixture of ortho-lpara-, mono-/diacylated compounds 27-31. The double acylation of pseudo-meta- dimethoxy[2.2]paracyclophane 18 is completely para-regioselective. Electrophilic substitution of pseudo-wera-bis(methoxycarbonyl)[2.2]paracyclophane 20 regioselectively generates the pseudo-gem-substitution pattern. Formylation of this substrate produces the monocarbonyl derivatives 35 only, whereas the Fe-catalyzed bromination may be directed towards mono- 36 or disubstitution 37 products chemoselectively by varying the reactions conditions. The diacylation and dibromination reactions of the respective achiral diphenol 12 and bis(methoxycarbonyl) 40 derivatives of the pseudo-para-structure retain regioselectivities which are characteristic for their pseudo-mefa-regioisomers. Imino ligands 26, 25, and 39, which were obtained from monoacyl- 22 and diacyldihydroxy[2.2]paracyclophanes 21, 38, are tested as chiral ligands in stereoselective Et2Zn addition to benzaldehyde producing 1-phenylpropanol with ee values up to 76%.
- Vorontsova, Natalia V.,Rozenberg, Valeria I.,Sergeeva, Elena V.,Vorontsov, Evgenii V.,Starikova, Zoya A.,Lyssenko, Konstantin A.,Hopf, Henning
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body text
p. 4600 - 4617
(2009/05/08)
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- Room temperature observation of p-xylylenes by 1H NMR and evidence for diradical intermediates in their oligomerization
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p-Quinodimethanes (p-QDMs) are reactive molecules that have been invoked as transient intermediates in a number of reactions. Dilute solutions of benzene-based p-QDMs, p-xylylene (1), α-methyl-p-xylylene (10), and 2,5-dimethyl-p-xylylene (11) can be prepared by fluoride-induced elimination of trimethylsilyl acetate from the appropriate precursor. It has been found that these solutions are stable enough to allow these reactive p-QDMs to be observed by 1H NMR spectroscopy at room temperature. For the first time, the 13C NMR spectrum of p-QDM 1 was observed. After several hours at room temperature, these p-QDMs form dimers, trimers, and insoluble oligomers. Formation of trimers provides evidence that p-QDMs 1, 10, and 11 dimerize by a stepwise mechanism involving dimeric diradicals as intermediates.
- Trahanovsky, Walter S.,Lorimor, Steven P.
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p. 1784 - 1794
(2007/10/03)
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- Diastereoselective Hartwig-Buchwald reaction of chiral amines with rac-[2.2]paracyclophane derivatives
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A Hartwig-Buchwald addition of a variety of chiral amines to rac-4-bromo-[2.2]paracyclophane and rac-trifluoromethanesulfonic acid (4-[2.2]paracyclophane) ester was performed with high diastereoselectivities. Kinetic racemic resolution of the starting materials was achieved, providing a rapid access to enantiomerically enriched 4-bromo-[2.2]paracyclophane and the corresponding enantiomerically pure [2.2]paracyclophane amines. Additionally, the first reaction of a secondary amine with a [2.2]paracyclophane halide was achieved.
- Kreis, Michael,Friedmann, Christian J.,Braese, Stefan
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p. 7387 - 7394
(2008/02/04)
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- An improved method for the regiospecific synthesis of polysubstituted [2.2]paracyclophanes
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4,16-Disubstituted, 4,7,12,15-tetrasubstituted, 4,8,12,16-tetrasubstituted and 4,5,7,8,12,13,15,16-octasubstituted [2.2]paracyclophanes can be prepared in significantly improved yields and excellent regiospecificities via the Winberg 1,6-elimination-dimerization reaction from substituted (4-methylbenzyl) trimethylammonium hydroxides. Using 2-chloro-phenothiazine instead of phenothiazine as a polymerization inhibitor results in a doubling of product yields. Georg Thieme Verlag Stuttgart.
- Chow, Hak-Fun,Low, Kam-Hung,Wong, King Y.
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p. 2130 - 2134
(2007/10/03)
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- Alternative general synthetic routes to [2.2]cyclophanes and [3.2]cyclophanes from [3.3]cyclophane-2,11-diones by photodecarbonylation, and a structural study of [3.2]metacyclophanes
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Photodecarbonylation of [3.3]cyclophane-2,11-diones, which are readily prepared by TosMIC coupling, affords [2.2]cyclophanes in high yield. This method also provides a general synthetic method for [3.2]cyclophan-2-ones by taking advantage of the fact that this photochemical reaction proceeds in a stepwise manner through [3.2]cyclophan-2-ones. A series of [2.2]cyclophanes, [3.2]cyclophanes, and [3.3]cyclophanes can thus be made available from the common precursor [3.3]cyclophane-2,11-diones. In sharp contrast to the preferred syn geometry of [3.3]metacyclophanes, [3.2] metacyclophanes adopt anti geometries and the aryl ring inversion process is observed by variable-temperature 1H NMR spectroscopy. In the crystalline state, the two aryl rings of anti-[3.2]metacyclophanes are almost parallel in spite of the unsymmetrical bridge length; they overlap only at the C-9 and C-17 positions, and the transannular distances are shorter than the corresponding distances in [3.3]metacyclophane-2,11-dione.
- Isaji, Hajime,Yasutake, Mikio,Takemura, Hiroyuki,Sako, Katsuya,Tatemitsu, Hitoshi,Inazu, Takahiko,Shinmyozu, Teruo
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p. 2487 - 2499
(2007/10/03)
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- Electro-organic reactions. Part 50. Quinodimethane chemistry. Part 1. Electrochemical generation and characterisation of p-quinodimethanes
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Quinodimethanes (QDMs) were generated cathodically from 1,4-bis(halogenomethyl)arenes, either by direct or by mediated reduction, and characterised using cyclic voltammetry in the 0.1 to 200 V s-1 range. Formal redox potentials (E°) were determined, including that, at -15°C, for the parent quinodimethane. Redox catalysis with organic mediators proved to be a convenient method for the generation of quinodimethanes from 1,4-bis(chloromethyl)arenes, either for electroanalytical study of the intermediates or for preparative purposes. The quinodimethanes electrogenerated from bis(chloromethyl)arenes in the presence of an organic mediator react to give good yields of poly(p-xylylenes) (PPXs). A copolymer, proposed to be random, is obtained by mediated co-electrolysis of 1,4-bis(chloromethyl)benzenes and 2,5-bis(chloromethyl)-1,4-dimethoxybenzene.
- Szunerits, Sabine,Utley, James H. P.,Nielsen, Merete F.
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p. 669 - 675
(2007/10/03)
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- Hemicarcerands that encapsulate hydrocarbons with molecular weights greater than two hundred
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Syntheses are reported for the globe-shaped hemicarcerands 1 and 2 composed of two rigid bowl-like units (polar caps) attached to one another at their rims through four OCH2C≡CC≡CCH2O units (equatorial spacers). Eight pendant CH3(CH2)4 groups in 1 and C6H5CH2CH2 groups in 2 attached in assemblies of four to each polar cap render the hosts soluble in organic solvents. The important shell-closing reactions 2Ar(OCH2C≡CH)4 + [O] → Ar(OCH2C≡CC≡CCH2O)4Ar went in 5-8% yields in pyridine-O2-Cu(OAc)2 to give a hemicarcerand free of pyridine. The higher solubility of 1 (compared to that of 2) in organic solvents led to an examination of its binding properties. By heating 1 dissolved either in potential guests or in 1,3,5-[(CH3)3C]3C6H3 (too large to enter 1) containing dissolved potential guests at 80-140 °C for 2-7 days, 1:1 hemicarceplexes mixed with the empty host were isolated in those cases when the potential guests were just small enough to enter the host's portals at high temperatures but large enough not to depart during isolation as stable solids. Thus, constrictive bonding played a large role in kinetic stabilization of the hemicarceplexes. The 1H NMR spectra of both the host and the guest were markedly modified upon complexation. The half-lives in hours of representative complexes dissolved in CDCl3 at 25 °C were as follows: 1·1,3,5-[(CH3)2CH]3C6H 3, 1628; 1·1,3,5-Et3C6H3, 960; 1·4-Et[2.2]paracyclophane, 24; 1·1,3-dimethyladamantane, 13.5; 1-[3.3]paracyclophane, 13; 1·tetradehydro[2.2]paracyclophane, 11; 1·[2.2]paracyclophane, 5; 1·4,12-dihydroxy[2.2]paracyclophane, 4; and 1·[2.3]paracyclphane, 0.5. Complexes of smaller guests such as CHCl3, ferrocene, adamantane, and 1,3,5-trimethylbenzene were unstable to room-temperature isolation conditions. Larger guests such as [3.4]paracyclophane and 4,12-dinitro[2.2]paracyclophane did not enter the portals of 1 at temperatures under which host 1 was stable, whereas smaller guests such as CH2Cl2 and pyridine entered and departed the host at 25 °C rapidly on the NMR time scale. Catalytic reduction (H2, PdC) of the eight acetylenic bonds of 1 produced an empty host of much more flexible structure, 3, whose binding properties have not yet been examined.
- Cram, Donald J.,Jaeger, Ralf,Deshayes, Kurt
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p. 10111 - 10116
(2007/10/02)
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- Selective Ketone Pyrolysis: New Examples
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The known ketone 4, the new paracyclophane ketones 6, 7, and 9-12 and the known hydrocarbons 5, 8, and 13 are obtained by successive thermal extrusion of carbon monoxide from the n>paracyclophane(ones)n 1, 2, and 3 (n=2,3,4).The X-ray structure analyses of the 20-membered 6 and the 26-membered ring 10 are reported. Key Words: Cyclophanes / Decarbonylation / Paracyclophanes / Pyrolysis / Ketone pyrolysis, selective
- Ott, Frank,Breitenbach, Joerg,Nieger, Martin,Voegtle, Fritz
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- The Effect of the Reactor Type on the Selectivity of Thermal Reactions of p-Xylene in Temperature Gradient Systems
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Thermal reactions of p-xylene were investigated in two kinds of reactors, batch type and flow type, with a large temperature gradient.Excellent differences of the resulting products were observed between these two types of reactors.As for a batch type reactor, 4,4'-dimethylbibenzyl was produced in a high yield with paracyclophane and toluene as by-products, and as for a flow type reactor, toluene was obtained as a major product with a low selectivity of 4,4'-dimethylbibenzyl, respectively.These results were different from those of the conventional fast flow pyrolysis method in which paracyclophane or poly(3,6-dimethylene-1,4-cyclohexadiene) was formed as a major product.These differences can be accounted for by the partial separation of a reaction mixture caused by the thermal diffusion effect, which arises when the mixture is subject to a temperature gradient.
- Kawakami, Shigenobu,Iwaki, Shingo,Nakada, Masahiro,Yamaguchi, Tatsuaki
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p. 1000 - 1004
(2007/10/02)
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- Samarium(II) Diiodide Mediated Coupling of Bis(bromomethyl)arenes. Facile Synthesis of n>Cyclophanes without using High-Dilution Techniques
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In the presence of samarium(II) diiodide (Sml2), coupling of 1,3- and 1,4-bis(bromomethyl)benzenes proceeds smoothly to give their cyclic and acyclic oligomers.Use of 1.2 equiv. of Sml2 gives 1,2-bis(3- and 4-bromomethylphenyl)ethanes, respectively, in 95percent yield, and the use of 5.0 equiv. of Sml2 affords n>metacyclophanes and n>paracyclpphanes (n = 2, 3 and 4), respectively, in satisfactory yields.By using 5.0 equiv. of Sml2, 2-bromo- and 2-methoxy-1,4-bis(bromomethyl)benzenes and 1,4- and 2,6-bis(bromomethyl)naphthalenes each give only one of several expected isomeric cyclophanes as the major cyclic oligomer.
- Takahashi, Senji,Mori, Nobuo
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p. 2029 - 2032
(2007/10/02)
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- Reductive Coupling by Chromium(0) - (Bibenzyl)- and (Stilbene)tricarbonylchromium(0) Complexes by a One-Pot Reaction from Benzylic Halides
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Reaction of Cr(CO)3(NH3)3 with benzylic mono-, di-, and trihalides leads to the formation of 1,2-diarylethanes, -ethenes, and diphenylethyne in satisfactory yields.Di(halomethyl)benzene derivatives yield product mixtures containing both reduction products and coupling products.With a higher excess in chromium(0), under otherwise unchanged reaction conditions, the corresponding (arene)tricarbonylchromium(0) complexes of the coupling products are formed in a one-pot reaction from the benzylic halides.
- Wey, Hans G.,Butenschoen, Holger
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- New Dienophiles and Dienes, III. On the Addition of Cyanoacetylene to Paracyclophane
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Heating a benzene solution of paracyclophane (2) in the presence of excess cyanoacetylene (1b) at 160 deg C in a sealed ampoule provides the novel 2:1-addition product 10, as well as the previously obtained cycloadducts 7-9.It is suggested that these Nenitzescu hydrocarbon systems are formed via the cyclobutadiene intermediates 17 and 18.This hypothesis is supported by the isolation of the side-products 1,2,4- and 1,2,3-tricyanobenzene (11 and 12).When a mixture of 7 and 8 is pyrolyzed at 220 deg C the novel dihydronaphthalene 24 is formed; the mechanism of this isomerization is discussed.The structures of 10 and 24 were confirmed by X-ray structure determination.
- Witulski, Bernhard,Ernst, Ludger,Hopf, Henning,Jones, Peter G.
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p. 2015 - 2022
(2007/10/02)
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- Transition Metal Catalyzed Oxidations, 3. Reaction of 4-Hydroxyparacyclophane with the Mimoun Molybdenum Oxodiperoxo Complex *Py*HMPT
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Treatment of 4-hydroxyparacyclophane (1) with the Mimoun molybdenum oxodiperoxo complex *Py*HMPT gives 3,4-dihydro-3-hydroxy-4-oxoparacyclophane (4).This dienone dimerizes at room temperature to afford the Diels-Alder adduct 5, whose structure was confirmed by X-ray analysis.
- Krohn, Karsten,Rieger, Hagen,Hopf, Henning,Barrett, David,Jones, Peter G.,Doering, Detlev
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p. 1729 - 1732
(2007/10/02)
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- Thermal Reactions of Xylenes in a Temperature Gradient System
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4,4'-Dimethylbibenzyl was produced in high yield with paracyclophane and toluene as by-products by the dehydrogenative coupling of p-xylene under a temperature gradient system, i.e., the thermal diffusion reactor.The results were different from those by the conventional tube reactors where far less selectivity for 4,4'-dimethylbibenzyl was obtained.
- Kawakami, Shigenobu,Iwaki, Shingo,Yu, Aiming,Nakada, Masashiro,Yamaguchi, Tatsuaki
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p. 893 - 896
(2007/10/02)
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- Process for the preparation of (2,2)-paracyclophane and derivatives thereof
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Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p-methylbenzyltrimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a dialkylether of mono- and poly-ethylene glycols having the formula: wherein R and R', which may be the same or different, represent alkyl groups having from 1 to 5 carbon atoms, and n is an integer from 1 to 5.
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- Process for the preparation of the parylene dimer
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An improved process is provided for the preparation of the dimer, 2,2-paracyclophane, which is useful as the starting material for parylene conformal coatings used in the electronics industry for the protection of various sensitive electronic components. The process comprises optimization of the normally low yield of dimer formed by the Hofmann elimination reaction of p-methylbenzyltrimethylammonium halide by conducting the elimination reaction in the presence of dimethysulfoxide and certain reaction promoters.
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- Process for the preparation of (2,2)-paracyclophane and derivatives thereof
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Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p-methylbenzyl-trimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a compound of the formula (I): wherein A represents an aromatic group, X an electron donor group, R hydrogen or an alkyl group containing from 1 to 4 carbon atoms, n is an integer from 1 to 6, and m is zero or an integer from 1 up to a value such that the sum m+n is equal to the number of substitutable positions in the aromatic group.
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- Process for the preparation of (2,2)-paracyclophane and derivatives thereof
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Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p-methylbenzyl-trimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a compound of the formula (I): wherein A represents an aromatic group, Y an electron donor group, X an electron acceptor group, and n is an integer from 1 to 3.
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- New η6-arene complexes of nickel(II): polyarene and fused arene systems
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Two reactions schemes have been employed to prepare a series of polyarene and fused arene-Ni(SiCl3)2 complexes.The first method was based on arenearene' exchange equilibria, and the second employed the production of the Ni(SiCl3)2 moiety in the presence of the desired arene by the reaction of (allyl)2Ni derivatives with HSiCl3.Arenes employed were biphenyl, 4,4'-dimethylbiphenyl, diphenylmethane, 1,2-diphenylethane, 4,4'-paracyclophane, naphthalene, and anthracene.Equilibria studies showed that the tendency to bind with the Ni(SiCl3)2 moiety was in the order 4,4'-paracyclophane>>toluene>diphenylmethane>1,2-diphenylethane>-biphenyl>naphthalene ca. anthracene>halobenzenes.Repeated attempts to bind two arene groups in the same molecule with two Ni(SiCl3)2 groups failed, as did attempts to prepare (Cl3Si)2Ni-arene-Ni(SiCl3)2 species.
- Choe, Seok-Burm,Klabunde, Kenneth J.
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p. 409 - 418
(2007/10/02)
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- A simple synthetic method of cyclophanes by Lanthanoid-mediated coupling of bis(bromomethyl)benzenes
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The coupling of bis(bromomethyl)benzenes with iodized samarium, cerium or misch metal gives cyclophanes in satisfactory yields in a short time.
- Takahashi, Senji,Mori, Nobuo
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- Process for the preparation of (2,2)-Paracyclophane and derivatives thereof
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Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p-methylbenzyl--trimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a dialkylether or mono- and poly-ethylene glycols having the formula:, R - O nR' (I), wherein R and R', which may be the same or different, represent alkyl groups having from 1 to 5 carbon atoms, and n is an integer from 1 to 5.
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- Process for the preparation of (2,2)-paracyclophane and derivatives thereof
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Process for the preparation of (2,2)-paracyclopha-ne or derivatives thereof by the Hofmann elimination of p-methyl-benzyl-trimethylammonium hydroxide or deriva-tives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a compound of the formula (I):, (R)m- A - (X)n (I), wherein A represents an aromatic group, X an electron donor group, R hydrogen or an alkyl group containing from 1 to 4 carbon atoms, n is an integer comprised between 1 and 6 and m is zero or an integer comprised between 1 and a value such that the sum m+n be equal to the number of substi-tuable positions in the aromatic group.
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- Process for the preparation of the parylene dimer
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An improved process is provided for the preparation of the dimer, 2,2-paracyclophane, which is useful as the starting material for parylene conformal coatings used in the electronics industry for the protection of various sensitive electronic components. The process comprises optimization of the normally low yield of dimer formed by the Hofmann elimination reaction of p-methylbenzyltrimethylammonium hydroxide by conducting the elimination reaction in the presence of a cosolvent and certain reaction promoters.
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- Process for the preparation of (2,2)-paracyclophane and derivatives thereof
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Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p.-methylbenzyltrimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a ketone of the formula: wherein R is hydrogen, a halogen, or an alkyl-carboxylic group.
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- Process for the preparation of (2,2)-paracyclophane and derivatives thereof
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Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p-methyl-benzyl-trimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elim-ination is carried out in the presence of a compound of the formula (I):, Y - A - ( X )n(I), wherein A represents an aromatic group, Y an electron donor group, X an electron acceptor group, and n is an integer from 1 to 3.
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- Process for the preparation of (2,2)-paracyclophane
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A process for the preparation of (2,2)-paracyclophane by conversion of p.methylbenzyltrimethylammonium halide to the corresponding hydroxide and by Hofmann elimination from p.methylbenzyltrimethylammonium hydroxide, wherein both reactions are carried out in the same aqueous solution of an alkaline hydroxide and in the presence of a copper or iron compound.
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- New Synthetic Method of Cyclophanes via Diselenacyclophanes
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Syntheses of cyclic diselenides through diselenolates and the following deselenation reactions by means of three ways were studied.The preparation of the cyclic diselenides in the presence of excess sodium borohydride gave thirty-eight diselenides containing diselenacyclophanes and alicyclic diseleno compounds in high yields in addition to two triple-bridged selenacyclophanes.Photodeselenation of the diselenides in tris(dimethylamino)phosphine afforded series of cyclophanes in much higher yields than those of the other two methods, i.e. benzyne-Stevens rearrangement/Raney nickel hydrogenolysis and pyrolytic deselenation at ca. 650 deg C.The present study demonstrates that the photodeselenation method combined with the synthesis of their precursor diselenides, is much superior to the conventional dechalcogenation methods.
- Higuchi, Hiroyuki,Tani, Keita,Otsubo, Tetsuo,Sakata, Yoshiteru,Misumi, Soichi
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p. 4027 - 4036
(2007/10/02)
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- Process for the preparation of [2,2]-paracyclophane
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A process for the preparation of [2,2]-paracyclophane comprises contacting aqueous p-methylbenzyltrimethylammonium hydroxide with sodium hydroxide or potassium hydroxide, in the presence of dimethyl sulfoxide, and preferably in the further presence of an inert water-immiscible organic solvent.
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- Flash Pyrolysis of Selenides. Syntheses of Bibenzyls, Olefins, and Related Compounds
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Pyrolyses of a series of selenides and diselenides were studied. Selenides and diselenides bound with an active methylene group like benzyl gave a variety of substituted bibenzyls and related ethane derivatives in high yields. Other diselenides were easily caused to cleave to give various aromatic and aliphatic olefins in good yields together with elemental selenium. Lepidopterene, paracyclophane, and benzocyclobutene were prepared by thermal cleavage of their corresponding phenylselenomethyl-substituted compounds as an application of the pyrolysis concerned.
- Higuchi, Hiroyuki,Otsubo, Tetsuo,Ogura, Fumio,Yamaguchi, Hachiro,Sakata, Yoshiteru,Misumi, Soichi
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p. 182 - 187
(2007/10/02)
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- DESELENATION OF DISELENACYCLOPHANES - A NEW SYNTHETIC METHOD OF CYCLOPHANES-
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Several diselenacyclophanes were prepared by coupling of bisselenocyanates and bis(bromomethyl)benzenes in good yields.The benzyne Stevens rearrangement-Raney Ni hydrogenolysis method gave good yields of double- and triple-layered cyclophanes from the diselenides, though the flash pyrolysis method gave them in low yields.
- Higuchi, Hiroyuki,Misumi, Soichi
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p. 5571 - 5574
(2007/10/02)
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