Mesitylene oxidations

Nitrations can be performed in homogeneous media, using tetramethylene sulfone or nitromethane (nitroethane) as solvent. A large variety of aromatic compounds have been nitrated with nitronium salts in excellent yields in nonaqueous media. Sensitive compounds, otherwise easily hydroly2ed or oxidized by nitric acid, can be nitrated without secondary effects. Nitration of aromatic compounds is considered an irreversible reaction. However, the reversibihty of the reaction has been demonstrated in some cases, eg, 9-nitroanthracene, as well as pentamethylnitrobenzene transnitrate benzene, toluene, and mesitylene in the presence of superacids (158) (see Nitration). 

Manufacture. The only current U.S. manufacturer of trimesic acid is Amoco Chemical Co. It is produced by oxidation of mesitylene (1,3,5-trimethylbenzene) via the Hquid-phase oxidation in acetic acid using the cobalt— manganese—bromine catalyst system (138). This is a variant of the system used to produce terephthaUc and isophthaUc acids as well as trimellitic anhydride. American Bio-Synthetics Corp. did produce it by batch oxidation of mesitylene with potassium permanganate. 

Economic Aspects. Trimesic acid being a smaH-volume chemical, availabiUty is in polyethylene-lined fiber dmms in 34- and 136-kg quantities. Mesitylene [108-67-8] the raw material, is readily available, and oxidation to trimesic acid presents no problems. The market size is dictated by commercial uses. 

Liquid-phase air oxidation of mesitylene with Co, Mn, and Bt catalysis produces 1,3,5-benzenetricarboxyhc acid [554-95-0] (trimesic acid) (10) (37) as does the oxidation with dilute nitric acid (qv). Amoco has oxidized mesitylene to trimesic acid on a small scale (see Phthalic acid and other BENZENECARBOXYLIC acids). Less vigorous stepwise oxidation of mesitylene can yield 3,5-dimethylbenzoic acid [499-06-9] (11) and 5-methyhsophthahc acid... 

The oxidation of the side-chain of an aiomatic hydiocaibon, when more than one is present, takes place in successive steps. Thus, mesitylene is converted into the following compounds on oxidation ... 

Mesitaldehyde may be prepared from mesitylmagnesium bromide by the reaction with orthoformate esters3 or ethoxy-methyleneaniline 3 from acetylmesitylene by oxidation with potassium permanganate,4 from mesitoyl chloride by reduction,5 from mesityllithium by the reaction with iron pentacarbonyl and from mesitylene by treatment with formyl fluoride and boron trifluoride,7 by treatment with carbon monoxide, hydrogen chloride, and aluminum chloride,8 or by various applications of the Gatterman synthesis.9-11... 

Mesitylene [Benzene, 1,3,5-tnmethyl-], 86 Z Met Gly Gly OEt [Gly cine,V-[Ar-[A-[(phenylmethoxy)carbonyl] -L-methionyl] glycyl] -, ethyl ester], 9 3 Methane, iodo-, hazard note 127 Methyl chlonde polystyrene [Benzene, diethenyl-, polymer with ethenyl-benzene, chloromcthylatcd], 96 Methyl iodide [Methane, iodo-], 79 Methyl mercaptan [Methanethiol], 73 Moffat oxidation, 99... 

Since the FeCp(C6H6)+ unit is robust towards oxidation even in concentrated sulfuric acid, oxidation of alkyl substituents upon boiling in aqueous KMn04 solution can be achieved and leads to carboxylic substituents. The mesitylene complex can be oxidized to the mono-, di-, or tri-carboxylic add depending upon the reaction conditions. In the latter case, the decomplexed trimesic acid is obtained [106, 107] Scheme XXII ... 

Nitrated Solvent Naphtha (N.S.N.). As nitration of crude solvent naphtha by the usual one-stage method results in yields that are too low, because of oxidation, E. Blecher et al (Ref 3) proposed nitrating only the refined material, and in two stages. The two-stage method is described in Colver, pp 255 686—87 (Ref 4). The product consists chiefly of 2,4,6-Trinitro-mesitylene (see under Mesitylene and Deriva- tives in this Vol), and 3,5,6-trinitropseudocumene, with small quantities of the nitrated products of xylene, ethylbenzene, etc... 

Dihydro-l,3-diborolenes are accessible as pentaorgano derivatives " and serve as ideal precursors of the diborolyl radieal. The formation of the radical and its interaction with a metal center is formally described as a metal oxidation. The resulting 2,3-dihydro-1,3-diborolyI ligand is either a three-electron donor or an anionic four-electron donor. l,3,4,5-Tetraethyl-2-methyl-2,3-dihydro-l,3-diborole reacts with [T -CpNi(CO)2] or (T7 -Cp>2Ni in hot mesitylene to yield a sandwich complex and a triple-decked complex ... 

Metal-vapor synthesis also prepares metallaboranes and metallacarboranes with oxidation of the metal. Thermally generated Ni, Co and Fe atoms react with the nido-carborane 2,6-C2B7H, and either cyclopentadiene, toluene, mesitylene, or... 

The synthesis of 3,5-dimethylbenzoic acid by oxidation of mesitylene by nitric acid has to be carefully monitored. Nitric acid has to be introduced very slowly... 

Note that in this case, the three carbonyl ligands are staggered relative to the carbon atoms in the benzene ring (as indicated by the dotted vertical lines). Similar compounds have also been prepared containing Mo and W. Methyl-substituted benzenes such as mesitylene (1,3,5-trimethylbenzene), hexamethylbenzene, and other aromatic molecules have been used to prepare complexes with several metals in the zero oxidation state. For example, Mo(CO)6 will react with 1,3,5-C6H3(C]T3)3, 1,3,5-trimethylbenzene, which replaces three carbonyl groups. 

Mesidine, t335 Mesitol, t387 Mesitylene, t359 Mesityl oxide, m370 Mesoxylurea, a73 Mesyl chloride, m36... 

Interesting examples of the addition of N-nucleophiles to nitrile oxides are syntheses of chelated Z-amidoxime, N-[2-(dimethylaminomethyl)phenyl]mesitylene-carboamidoxime (118), and pyranosyl amidoximes (119) from the respective nitrile oxides and amines. Aromatic aldoximes undergo unusual reactions with chloramine-T (4 equiv, in refluxing MeOH). N-(p-toly 1 )-N-(p-tosy 1 )benzamides are formed via addition of 2 equiv of chloramine-T to the intermediate nitrile oxide followed by elimination of sulfur dioxide (120). 

Nitrile oxide-BF3 complexes can also be used as electrophilic moieties with aromatic systems. Introducing BF3 into a mixture of 2,6-dichlorobenzonitrile oxide and mesitylene in hexane, gave 88% Z-2, 6 -dichloro-2,4,6-trimethyl-benzophenone oxime (128). 

Mesitylene, condensation with dichioro-methyl methyl ether, 47, 1 oxidation with peroxytrifluoroacetic acid and boron trifluoridc, 48, 90... 

Mesitoic acid has been prepared by carbonation of mesityl-magnesium bromide 2-4 by hydrolysis of its amide prepared by condensation of mesitylene with carbamyl chloride under the influence of aluminum chloride 6 by oxidation of isodurene with dilute nitric acid 6-7 by distillation of 2,4,6-trimethylmandelic acid (low yield) 8 by dry distillation of 2,4,6-trimethyIphenyl-glyoxylic acid 9 by oxidation of the latter with potassium permanganate 10 and by treating 2,4,6-trimethylphenylglyoxylic acid with concentrated sulfuric acid in the cold11 or with heating.12... 

Dipolar addition of mesitylene nitrile oxide with 4,7-phenanthroline 159 gave a 2 1 adduct 160 with a very low yield (Equation 19), the dearomatization of the pyridine ring giving rise to a more reactive double bond which, in turn, underwent cyclization <1998T9187>. 

Mesitylene, production from acetone, 1 164 Mesityl oxide, 14 589-590 characteristics of, 16 337 hydrogenation, 16 337-338 hydrogen peroxide treatment of, 16 338 Z-menthol from, 24 520 production of, 16 336-337 production from acetone, 1 164, 174 Mesogenic diols, 25 460 Mesogenic molecules, solids of, 15 82 Mesogens, 24 53, 54 Mesomixing, 16 683 Mesomorphic behavior, 24 53-54 Mesomorphic phase transitions, 15 102 Mesomorphism, 15 81. See also Liquid crystalline materials Mesophase pitch-based carbon fiber, 26 734-735... 

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