ChemInform Abstract: Oxidative Halogenation of Aromatic Compounds by the System Pb3O4‐Hal‐‐CF3COOH.

Makhon'kov, D. I.; Cheprakov, Andrei V.; Rodkin, Mikhail A.; Serguchev, Yu. A.; Davydova, V. G.; Beletskaya, I. P.

doi:10.1002/chin.198821108

Cited by 5 publications

(6 citation statements)

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“…HCl−H 2 O 2 can also be used by adding hydrogen peroxide in a semibatch manner . Trifluoroacetic acid is used as the solvent. Oxygen can also be used directly with H 2 O 2 in the presence of different types of catalysts. − In this work, 4-methylbenzenesulphonic acid, 4-methylbenzoic acid, 4aminobenzoic acid, and 4-hydroxybenzoic acid were chlorinated by using HCl−H 2 O 2 in a less expensive solvent such as water or acetic acid.…”

Section: Introductionmentioning

confidence: 99%

Oxidative Chlorination, Desulphonation, or Decarboxylation To Synthesize Pharmaceutical Intermediates: 2,6-Dichlorotoluene, 2,6-Dichloroaniline, and 2,6-Dichlorophenol

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Chandalia

1998

Org. Process Res. Dev.

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An alternative manufacturing process scheme was developed for 2,6-dichlorotoluene, 2,6-dichloroaniline, and 2,6-dichlorophenol, involving oxidative chlorination after protection of the starting material in the para position followed by deprotection involving desulphonation or decarboxylation. Oxidative chlorination of 4-methylbenzenesulphonic acid, 4-methylbenzoic acid, 4-aminobenzoic acid, and 4-hydroxybenzoic acid by using HCl−H2O2, and their subsequent desulphonation or decarboxylation, gave a 60−75% yield of the desired product.

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Section: Introductionmentioning

confidence: 99%

Oxidative Chlorination, Desulphonation, or Decarboxylation To Synthesize Pharmaceutical Intermediates: 2,6-Dichlorotoluene, 2,6-Dichloroaniline, and 2,6-Dichlorophenol

and

Chandalia

1998

Org. Process Res. Dev.

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“…It was stated previously that toluene reaction with cerium ammonium nitrate in acetic acid resulted in nitration with the formation of a mixture of isomeric nitrotoluenes [7].…”

Section: Iа Ibmentioning

confidence: 99%

Reactions of 2-(4-hydroxyanilino)-1,4-naphthoquinones with cerium ammonium nitrate and pyridinium chlorochromate

2012

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Reactions of 2-(4-hydroxyarylamino)-1,4-naphthoquinones with cerium ammonium nitrate or pyridinium chlorochromate depending on the structure of initial substrate and the type of reagent led to the formation of 2-chloro-3-(4-cyclohexa-2,5-dienylideneamino)-1,4-dihydronaphthalene-1,4-diones, 2-(4-hydroxy-3-nitrophenylamino)-1,4-naphthaquinones, and also to simultaneous oxidation and chlorination.Both polycyclic quinones and quinone imines possess practically important properties [1], but the information on polycyclic compounds containing in a single molecule both quinoid and quinone imine fragments is virtually absent. In this study we examined the experimental approaches to this type compounds.By the reaction of 2,3-dichloro-1,4-naphthoquinone (Iа), 5-hydroxy-2,3-dichloro-1,4-naphthoquinone (Ib) with p-aminophenols, and also by the direct amination of 1,4-naphthoquinone (Ic) 2-(4-hydroxyarylamino)-1,4-naphthoquinones IIа-IIf were obtained and their behavior with respect to oxidants was investigated. We used as oxidants cerium ammonium nitrate and pyridinium R 1 O Cl Cl O Iа, Ib H 2 N OH R 2 R 1 O Cl NH O IIа _ IId OH R 2 R 1 O Cl N O IIIа _ IIIc O R 2 (NH 4 ) 2 Ce(NO 3 ) 6 I, R 1 = H (a), OH (b); II, R 1 = R 2 = H (а); R 1 = H, R 2 = Me (b); R 1 = OH, R 2 = Me (c), H (d); III, R 1 = R 2 = H (а), R 1 = H, R 2 = Me (b), R 1 = OH, R 2 = Me (c).chlorochromate, which had been successfully applied formerly to the preparation of some quinones and quinone imines [2, 3]. The oxidation of 2-chloro-3-(4-hydroxyphenylamino)-1,4-naphthoquinones IIа-IIc with cerium ammonium nitrate led to the formation of the corresponding 2-chloro-3-(4-oxocyclohexa-2,5-dienylideneamino)-1,4-dihydronaphthalene-1,4-diones IIIа-IIIc (the substituents are listed according to the Latin alphabet in order to conserve the numeration of atoms) (Scheme 1).2-Chloro-8-hydroxy-3-(4-hydroxyphenylamino)-1,4-naphthoquinone (IId) was oxidized to the corresponding quinone imine (IIId) with pyridinium chlorochromate Scheme 1.

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“…Other systems which gave >=3% meta-nitrotoluene include: nitronium tetrafluoroborate in sulfolane [15], N 2 O 5 /tetraethylammonium tetrafluoroborate in acetonitrile under anodic conditions [16], N 2 O 4 /tetraethylammonium tetrafluoroborate in acetonitrile under electrolytic conditions [17], tetra-n-butylammonium nitrate/trifluoroacetic anhydride in nitromethane [18], calcium nitrate in nitric acid [19], nitric acid/acetic anhydride in the presence of zeolite-beta and a solvent [20], and anhydrous vanadium nitrate in dichloromethane [21]. In the following cases the proportion of meta isomer was not reported (thus presumed not to be notably low): ceric ammonium nitrate/trifluoroacetic acid (3 day reaction) [22], methyl nitrate under radiolysis [23], nitryl chloride in aqueous trifluoroacetic acid [24], N 2 O 4 -oxygen in 1,2-dichloroethane in the presence of zeolite beta [25] and ammonium nitrate/trifluoroacetic anhydride in the ionic liquid emim trifluoroacetate [26]. More recently (post-2002) work has been reported using either ceric ammonium nitrate-acetic anhydride [27], nitric acid-lanthanide complexes [28], potassium nitrate-BF 3 complexes [29] or nitric acid mixtures in ionic liquids [30][31][32], but all of these systems gave meta contents in excess of 3%.…”

Section: Toluene Nitration -Initial Stagesmentioning

confidence: 99%

Annual Industrial Capabilities Report to Congress

Farnborough¹

2008

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The US Department of Defense requires an environmentally benign synthesis route for the manufacture of military grade trinitrotoluene (TNT) which eliminates the production of redwater arising from the sulfiting process for removing unsymmetrical trinitrotoluene isomers. QinetiQ has found that by using a novel nitrating system, N2O5 in dichloromethane, the proportion of meta-substituted nitrotoluenes can be reduced to 1.3-1.5%, instead of the 4-5% levels in current processes. Additional improvements have been made to the following di-and tri-nitration steps by using alternatives to traditional mixed (sulfuric-nitric) acid systems, namely 100% nitric acid and N2O5-sulfuric acid respectively, resulting in reduced emissions of pollutants (NOx offgas and tetranitromethane). As a result, TNT with a set point within 0.3 deg. C of the Mil. Spec. (80.2 deg. C) can be made by the QinetiQ process, without the need for sulfite washing; one recrystallization raises this figure to 80.6 deg. C. A study of the process economics has shown that the cost (at 4.5 million lb per annum scale) is not disproportionately greater than current processes.

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ChemInform Abstract: Oxidative Halogenation of Aromatic Compounds by the System Pb3O4‐Hal‐‐CF3COOH.

Abstract: Chlorination, bromination, or iodination of the benzene derivatives (I) with the system minium ‐ alkali halide ‐ trifluoroacetic acid proceeds at room temperature without side reactions, producing mixtures of the o‐(II) and p‐derivatives (III).

Cited by 5 publications

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Oxidative Chlorination, Desulphonation, or Decarboxylation To Synthesize Pharmaceutical Intermediates: 2,6-Dichlorotoluene, 2,6-Dichloroaniline, and 2,6-Dichlorophenol

Oxidative Chlorination, Desulphonation, or Decarboxylation To Synthesize Pharmaceutical Intermediates: 2,6-Dichlorotoluene, 2,6-Dichloroaniline, and 2,6-Dichlorophenol

Reactions of 2-(4-hydroxyanilino)-1,4-naphthoquinones with cerium ammonium nitrate and pyridinium chlorochromate

Annual Industrial Capabilities Report to Congress

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