- Photo-induced deep aerobic oxidation of alkyl aromatics
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Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical industry. Presently, the industrial manufacture of benzoic acids and benzene polycarboxylic acids (BPCAs) is mainly based on the deep oxidation of polyalkyl benzene, which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting MeBr and corrosion hazards of production equipment. In this report, photo-induced deep aerobic oxidation of (poly)alkyl benzene to benzene (poly)carboxylic acids was developed. CeCl3 was proved to be an efficient HAT (hydrogen atom transfer) catalyst in the presence of alcohol as both hydrogen and electron shuttle. Dioxygen (O2) was found as a sole terminal oxidant. In most cases, pure products were easily isolated by simple filtration, implying large-scale implementation advantages. The reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks. [Figure not available: see fulltext.].
- Wang, Chang-Cheng,Zhang, Guo-Xiang,Zuo, Zhi-Wei,Zeng, Rong,Zhai, Dan-Dan,Liu, Feng,Shi, Zhang-Jie
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p. 1487 - 1492
(2021/07/10)
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- An Evaluation of Multiple Catalytic Systems for the Cyanation of 2,3-Dichlorobenzoyl Chloride: Application to the Synthesis of Lamotrigine
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2,3-Dichlorobenzoyl cyanide is a key intermediate in the synthesis of Lamotrigine. An assessment of various catalytic systems for the cyanation of 2,3-dichlorobenzoyl chloride with cyanide salts is described. High-throughput experimentation identified many conditions for effecting the requisite chemistry, including amine bases and phase-transfer catalysts, as well as catalyst-free conditions utilizing acetonitrile as a polar cosolvent. A novel catalyst, CuBr2, was identified by consideration of the possible oxidation of Cu(I) during high-throughput screening experimentation. CuCN was found to be the best cyanide source for achieving clean conversion; however, the solubility of CuCN was the major factor limiting reaction rate under many conditions. Improving CuCN solubility by using acetonitrile as solvent enhanced the reaction rate even in the absence of the catalysts tested but significantly complicated isolation of the product. With no acetonitrile cosolvent, phase-transfer catalysts such as tetrabutylammonium bromide (TBABr) are effective; however, use of TBABr led to inconsistent reaction profiles from run-to-run, due to an unexpected clumping of the CuCN solid. Switching to cetyltrimethylammonium bromide (CTAB) alleviated this clumping behavior, leading to consistent reactivity. This CTAB-catalyzed process was scaled up, giving 560 kg of 2,3-dichlorobenzoyl cyanide in 77% isolated yield.
- Leitch, David C.,John, Matthew P.,Slavin, Paul A.,Searle, Andrew D.
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p. 1815 - 1821
(2017/11/24)
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- Direct conversion of aromatic aldehydes into benzamides via oxidation with potassium permanganate in liquid ammonia
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Oxidation of aromatic aldehydes by KMnO4 in liquid ammonia gives amides directly. The reaction proceeds satisfactorily when the aldehydes are activated by electron-withdrawing substituents on the ring.
- Antoniak, Damian,Sakowicz, Arkadiusz,Loska, Rafa?,Makosza, Mieczys?aw
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supporting information
p. 84 - 86
(2015/02/05)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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p. 5781 - 5788
(2014/07/22)
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- INHIBITORS OF STEAROYL-COA DESATURASE
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Provided herein are compounds of the formula (I): as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of diseases such as, for example, obesity.
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- Proton transfer equilibria between disubstituted benzoic acids and carbinol base of crystal violet in apolar aprotic solvents. Chemometric analysis of disubstituent effects on the strength of benzoic acid in chlorobenzene
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Proton transfer equilibria in chlorobenzene between a set of di-substituted (2,3-,2,5-,2,6-, 3,5-dichloro and difluoro) benzoic acids including the corresponding mono-substituted acids and the carbinol base of crystal violet have been studied spectrophotometrically. To investigate the effect of disubstitution at ortho- and/or meta- positions on the strength of benzoic acid, the results have been analysed chemometrically on the basis of Fujita Nishioka's multiparameter approach and the assumption of additivity for substituent effects. The model employed explains 94% of the variance for the disubstituent effects on log K. It is observed that the substituent effect is contributed by ordinary electronic and proximity electronic effects in an almost equal ratio (52:48).
- Sen Gupta, Susanta K.,Shrivastava, Ruchi
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p. 369 - 373
(2008/09/19)
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- WO3/70% TBHP/aqueous NaOH: An efficient catalytic combination for the selective oxidation of methylarenes and alkyl aryl ketones to benzoic acids
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A new solvent-free, reusable catalytic combination consisting of WO 3/70% TBHP/aqueous NaOH has been described for the direct oxidation of methylarenes and acetophenones to the corresponding benzoic acids in high yields. Alkylarenes are oxidized to the corresponding aromatic ketones or benzylic alcohols depending upon whether NaOH is used or not. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Shaikh, Tanveer Mahammad Ali,Sudalai, Arumugam
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experimental part
p. 4877 - 4880
(2009/05/30)
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- METHOD FOR PREPARING LAMOTRIGINE AND ITS INTERMEDIATE 2,3-DICHLOROBENZOYL CHLORIDE
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The invention relates to an improved method for preparing 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine, also commonly known as lamotrigine. The present invention also relates to a method for preparing the intermediate 2,3-dichlorobenzoyl chloride, which comprises the synthesis by photochlorination of 2,3-dichlorobenzotrichloride followed by hydrolysis thereof. Said 2,3-dichlorobenzoyl chloride intermediate is useful for preparing lamotrigine.
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Page/Page column 16
(2010/11/29)
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- Proton mobility in 2-substituted 1,3-dichlorobenzenes: "ortho" or "meta" metalation?
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Nine 1,3-dichlorobenzene congeners were selected as model compounds to assess the relative rates of proton abstraction from 4- and 5-positions ("ortho" vs. "meta" metalation). Using lithium 2,2,6,6-tetramethylpiperidide as the basic reagent, the chlorine-adjacent 4-position underwent metalation exclusively. In contrast, attack at the chlorine-remote 5-posi" tion became significant even in the case of moderately sized 2-substituents (such as dimethylamino or ethyl) when secbutyllithium was employed. The "ortho/para" (4-/5-) ratios ranged from 80:20 to 65:35. The more pronounced "meta-orienting" effect of silicon as opposed to carbon substituents can be attributed to dissimilarities in the n polarization of the aromatic ring. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Schlosser, Manfred,Heiss, Christophe,Marzi, Elena,Scopelliti, Rosario
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p. 4398 - 4404
(2007/10/03)
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- NaIO4-mediated selective oxidation of alkylarenes and benzylic bromides/alcohols to carbonyl derivatives using water as solvent
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A new transition-metal-free, sodium metaperiodate (NaIO4)- mediated direct oxidation of methylarenes and benzylic bromides to the corresponding aromatic carboxylic acids is described. Under the same reaction conditions, benzylic alcohols are selectively oxidized to afford the corresponding aldehydes in good yields without undergoing overoxidation. Unprecedentedly, oxidation of benzyl bromide, toluene, or benzyl alcohol with NaIO4 underwent nuclear bromination followed by oxidation to give 4-bromobenzoic acid in 60-79% yields.
- Shaikh, Tanveer Mahammad Ali,Emmanuvel, Lourdusamy,Sudalai, Arumugam
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p. 5043 - 5046
(2007/10/03)
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- Process for the preparation of 6-(2,3-dichlorophenyl)-1,2,4-triazine-3,5-diamine, commonly known as lamotrigine
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A process for the preparation of 6-(2,3-dichlorophenyl)-1,2,4-triazine-3-5-diamine (lamotrigine) of the formula I: 2,3-Dichloronitrobenzene in C1-C6aliphatic alkanol is hydrogenated at 55-90 psi gas pressure using metal catalyst at 27-35° C. 2,3-Dichloroaniline is diazotised and cyano-de-diazonised with metal cyanide at 65-80° C. 2,3-Dichlorobenzonitrile is hydrolysed and 2,3-dichlorobenzoic acid is chlorinated at 55-130° C. Cyano-de-halogenation of 2,3-dichlorobenzoyl chloride is carried out with a metal cyanide and alkali metal iodide by refluxing in an aprotic solvent under an inert atmosphere. 2,3-Dichlorobenzoyl cyanide is condensed with aminoguanidine bicarbonate in an organic solvent in acidic conditions using catalyst at 90-125° C. followed by insitu cyclisation of the Schiff's base by refluxing in an aliphatic alkanol with base. Crude lamotrigine is purified.
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Page/Page column 7-8
(2010/01/31)
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- Method for preparing aromatic compounds
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A method for synthesizing aromatic compounds by selectively dehalogenating aromatic starting materials is provided. Compounds may be prepared which are substituted with fluoro, chloro or bromo. The method may be used to remove halogen atoms from sites at which halogenation is not desired, and to form substantially pure halogenated compounds from mixtures of starting materials. The method uses a copper containing dehalogenation agent and an acid with the dehalogenation being controlled by a substituent such as a carboxylic acid, amide, ester, aldehyde, ketone or cyano on the aromatic ring.
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- Method for preparing aromatic compounds
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A method for synthesizing aromatic compounds by selectively dehalogenating aromatic starting materials is provided. Compounds may be prepared which are substituted with fluoro, chloro or bromo. The method may be used to remove halogen atoms from sites at which halogenation is not desired, and to form substantially pure halogenated compounds from mixtures of starting materials. The method uses a copper containing dehalogenation agent and an acid with the dehalogenation being controlled by a substituent such as a carboxylic acid, amide, ester, aldehyde, ketone or cyano on the aromatic ring.
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- Process for producing carboxylic acids
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A process for producing a carboxylic acid which comprises reacting an organic chloride having at least one chloride atom on its ring of a substituted or unsubstituted, aromatic or heterocyclic hydrocarbon with carbon monoxide in the presence of an inorganic base or an organic base and water at a reaction temperature of 150° to 300° C., and preferably 160° to 300° C., by using as catalysts a palladium compound and a phosphine compound represented by the general formula (III): wherein R is an alkyl group or a substituted or unsubstituted phenyl group, and X is an alkylene group having 1 to 6 carbon atoms, STR1 or a binaphthyl group.
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- Electrosynthesis of aryl-carboxylic acids from chlorobenzene derivatives and carbon dioxide
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The electrocarboxylation of a large variety of chlorobenzenic compounds is achieved in N,N-dimethylformamide by constant current electrolysis between a stainless steel cathode and a sacrificial magnesium anode in a diaphragmless cell. Substituted benzoic acids are obtained in high yield in simle conditions thus avoiding the usual preparation of organometallic intermediates.
- Heintz, Monique,Sock, Oumar,Saboureau, Christophe,Perichon, Jacques,Troupel, Michel
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p. 1631 - 1636
(2007/10/02)
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