- NEW PROCESSES FOR PREPARING 4-SUBSTITUTED IMIDAZOLES
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There is provided a novel process for the preparation of a compound of formula (I), (Formula (I)). There is also provided novel processes to intermediates of the compound of formula (I), as well as novel intermediates themselves.
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Page/Page column 40; 41
(2013/03/26)
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- Microwave assisted solid additive effects in simple dry chlorination reactions with n-chlorosuccinimide
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Solid additives participate in the dry microwave assisted chlorination reaction of N-chlorosuccinimide with the xylenes affecting both yields and chemoselectivities. Total yields can be increased up to nine times for simple alkylaromatics and chemoselectivities can be altered according to the desired ring or α-side chlorination product by choosing the appropriate additive. We believe that in these reactions the solid additives play a very important role by increasing yields and affecting chemoselectivities, as well as behaving as microwave energy absorbers that consequently aid the transfer of heat to the active reagents.
- Bucos, Madalina,Villalonga-Barber, Carolina,Micha-Screttas, Maria,Steele, Barry R.,Screttas, Constantinos G.,Heropoulos, Georgios A.
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experimental part
p. 2061 - 2065
(2010/04/26)
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- Regiospecific chlorination of xylenes using K-10 montmorrillonite clay
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Regiospecific chlorination of xylenes has been developed by employing NCS as a reagent and K-10 montmorrillonite clay as a solid support. Copyright Taylor & Francis Group, LLC.
- Thirumamagal,Narayanasamy, Sureshbabu,Venkatesan
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body text
p. 2820 - 2825
(2009/05/07)
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- Chlorination of aromatic substrates catalyzed by the phthalocyanine complexes
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The chlorination of benzene, toluene, and o-xylene with molecular chlorine in the presence of the phthalocyanine complexes of different structures was studied. The transformations of the catalysts during the reaction were investigated.
- Ivanov,Tsentalovich,Kogan,Tomilova,Zefirov
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experimental part
p. 1676 - 1679
(2011/04/23)
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- PROCESS FOR HALOGENATION OF BENZENE AND BENZENE DERIVATIVES
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In a process of halogenation of benzene or benzene derivatives, di-substituted halobenzene derivatives having para-aromatic compounds or tri-substituted halobenzene derivatives having 1,2,4-substituted aromatic compounds are selectively produced. In halogenation of benzene or benzene derivatives, a fluorine-containing zeolite catalyst such as L-type zeolite, or a zeolite catalyst having the crystal size of at most 100 nm is used. The reaction is preferably effected in the presence of a solvent, and the solvent is preferably a halogenated compound.
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Page/Page column 11; 12
(2008/06/13)
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- Process for the nuclear chlorination of ortho-xylene
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A process for the chlorination of the nucleus of ortho-xylene comprises reaction of ortho-xylene and a chlorinating agent in the presence of a Friedel-Crafts catalyst and chlorine-substituted 2,8-dimethyl-phenoxathiine as a cocatalyst.
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Page column 4-5
(2008/06/13)
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- Process for the hydrodechlorination of nuclear chlorinated ortho-xylenes
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A process for the hydrodechlorination of nuclear-chlorinated o-xylene and recovery of o-xylene with the formation of HCl comprises hydrogenation of the nuclear-chlorinated o-xylene at a noble metal containing catalyst at 220-360 degrees C.
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- Liquid-Phase Decarboxylation of Aromatic Haloformates: A New Access to Chloro- and Fluoroaromatics
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The treatment of phenyl chloroformates 1 with a Lewis acid in the liquid phase resulted in decarboxylation to the corresponding chloroaromatics 2. Fluoroaromatic compounds were synthesized from phenylchloroformates 1 through a sequential fluorination/decarboxylation in the liquid phase by treatment with excess anhydrous hydrogen fluoride under mild conditions. In all cases, yields were increased by performing the reaction in 1,2,4-trichlorobenzene, which is inert to Friedel-Crafts reactions.
- Lui, Norbert,Marhold, Albrecht,Rock, Michael H.
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p. 2493 - 2496
(2007/10/03)
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- Versatility of Zeolites as Catalysts for Ring or Side-Chain Aromatic Chlorinations by Sulfuryl Chloride
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Zeolites catalyze chlorination of aromatics by sulfuryl chloride SO2Cl2.It is possible by an appropriate choice of the catalyst to effect at will, with very high selectivity, either the ring or the side-chain chlorination.Zeolite ZF520 is the choice catalyst for the former, because of its high Broensted acidity.Zeolite NaX (13X) is a fine catalyst for the latter, free-radical chlorination; the reaction is best effected in the presence of a light source; the catalyst can be reused many times with no loss in activity.Both reaction modes, the ionic (ring chlorination)and the radical (side-chain substitution), are likely to occur outside of the channel network in the microporous solid.The effects of various experimental factors - such as the nature of the solvent, the reaction time and temperature, the Broensted acidity of the solid support, the presence of radical inhibitors, and the quantity of catalysts - were investigated.The procedures resulting from this study are very easy to implement in practice and are quite effective.
- Delaude, Lionel,Laszlo, Pierre
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p. 5260 - 5269
(2007/10/02)
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- Evidence for the Reactive Spin State of 1,4-Dehydrobenzenes
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Two approaches have been used to investigate the spin state(s) of 1,4-dehydrobenzene produced in the solution thermolysis of diethynyl olefins.One method relies on the "spin correlation effect" which postulates a relationship between the spin state of a caged radical pair and the ratio of cage and escape reactions (C/E) which may occur in the pair.When the 2,3-di-n-propyl-1,4-dehydrobenzene biradical (4) abstracts hydrogen from 1,4-cyclohexadiene, a radical pair is generated.If a mixture of 1,4-cyclohexadiene-d0 and-d4 is employed, it is possible, by performing a VPC-MS analysis, to determined the C/E ratio leading from the radical pair to the reduced product, o-dipropylbenzene (10).When this method was applied to the reaction of (Z)-4,5-diethynyl-4-octene (3), C/E was found to be 0.6, independent of the concentration of 1,4-cyclohexadiene (between 0.1 and 10 M) in the chlorobenzene reaction solution.This result indicates the presence of the singlet state of 4 in the reaction of 3.Additional support for this analysis came from the reaction of 3,4-dimethyl-1,5-hexadiyn-3-ene (11) in hexachloroacetone solvent in a 1H NMR probe.The single polarized signal (emission) observed is attributed to the major product of the reaction, 1,4-dichloro-2,3-dimethylbenzene (12), obtained by chlorine abstraction from the solvent.The interpretation of this result indicates solvent trapping of the singlet state of the intermediate 2,3-dimethyl-1,4-dehydrobenzene, consistent with the chemical trapping study.These experimental approaches indicate that at least a substantial portion of the products formed from 1,4-dehydrobenzenes at elevated temperatures arise from the singlet state of the biradical.This suggests that either the singlet is the ground state or, if the triplet is lower in energy, the rate of intersystem crossing from the singlet must be 9 s-1 at 200 deg C.
- Lockhart, Thomas P.,Bergman, Robert G.
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p. 4091 - 4096
(2007/10/02)
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- Manufacture of o-benzyltoluenes
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A process for the manufacture of o-benzyltoluenes by reaction of o-xylyl halides with benzenes in the presence of sulfuric acid or in the presence of phosphoric acid and adjuvants or in the presence of sulfuric acid and adjuvants. The products are starting materials for the manufacture of anthracene and anthraquinone and their derivatives.
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