1.3.5- Trimethyl-2,4,6-tris benzene

Attempts to prepare 1 from some other precursors were largely unsuccessful N, N A -(cyclopropane-l,2,3-trimethyl)-tris(dimethylamine oxide) decomposed unspecifically above 250 C and pyrolysis of l,2,3-tris(acetoxymethyl)cyclopropane gave mainly benzene its gas-phase pyrolysis at 570-580 C produced a mixture of at least fifteen compounds containing perhaps a small amount of 1. ... 

This chapter covers recent developments in the title area published during 2014. As last year, little work has appeared in the literature apart from the preparation of novel pentacoordinated compounds. For instance, a chemoselective synthesis of 2,2,2-trichloro-4(5)-(dichloro-phosphoryloxy)-l,3,2X -benzodioxaphospholes which were obtained in a multi-step reaction starting from 1,2,3- and l,2,4-tris(trimethyl-siloxy)benzenes has been reported. Of note also are investigations describing intramolecular N-H cleavage of ammonia, allg lamines and aryl amines by tricoordinate phosphorus compounds furnishing pentacoordinated adducts. 

If this electrostatic treatment of the substituent effect of poles is sound, the effect of a pole upon the Gibbs function of activation at a particular position should be inversely proportional to the effective dielectric constant, and the longer the methylene chain the more closely should the effective dielectric constant approach the dielectric constant of the medium. Surprisingly, competitive nitrations of phenpropyl trimethyl ammonium perchlorate and benzene in acetic anhydride and tri-fluoroacetic acid showed the relative rate not to decrease markedly with the dielectric constant of the solvent. It was suggested that the expected decrease in reactivity of the cation was obscured by the faster nitration of ion pairs. 

Fig. 4. l,3,5-Trimethyl-2,4,6-tris(3,5-di-/ i -butyl-4-hydroxybenzyl)benzene [1709-70-2] derived from mesitylene. 

Subsequently, rate coefficients were determined for the zinc chloride-catalysed bromination of benzene, toluene, i-propyl-benzene, r-butylbenzene, xylenes, p-di-f-butylbenzene, mesitylene, 1,2,4-trimethyl-, sym-triethyl-, sym-tri-f-butyl-, 1,2,3,5-and 1,2,4,5-tetramethyl- and pentamethylbenzenes, all at 25.4 °C and in acetic acid, and it was shown that the reaction was inhibited by HBr.ZnCl2 which accumulates during the bromination and was considered to cause the first step of the reaction (formation of ArHBr2) to reverse320. The second-order coefficients for bromination of o-xylene at 25.0 °C were shown to be inversely dependent upon the hydrogen bromide concentration and the reversal of equilibrium (155)... 

A tripodal imidazolium salt 13 was obtained by Howarth from enantiopure imidazoles 14 (Scheme 10) by reaction with l,3,5-tris(bromomethyl)-2,4,6-trimethyl benzene [19]. 

Experimental Preparation of Spironaphthooxazine 33 (N-Bu). Tri-ethylamine (3.54 g, 35 mmol) was added to a suspension of 2,3,3-trimethyl-iV-butylindolinium iodide (12.0 g, 35 mmol) and o-nitrosonaphthol (6.1 g, 35 mmol) in EtOH (100 ml) under stirring. The mixture was refluxed for 2 h, cooled, and evaporated under reduced pressure. The residue was chromatographed on silica gel with benzene as an eluent, and then recrystallized from methanol to give spiro(Af-butylindolinonaphthooxazine) 33 (6.6 g, yield 51%). 

Methylation was accomplished by direct conversion of the acetyl derivative as previously described. The final product contained 45% OCHs. Molecular weight determinations in benzene gave values representing 18 to 19 D-fructose residues. Hydrolytic products of the methyl derivative were separated by conversion to benzoyl derivatives. The trimethylfructose was identified as 3,4,6-trimethyl-D-fructofuranose by its phenylosazone. The authors conclude that the ratios 1 3 1 exist among the di-, tri-, and tetramethyl-D -fructoses produced by the hydrolysis. 

The ESR/ENDOR TT-spin populations p in the radical anion of 1.4-di[tris(trimethyl-silyl)silyl]benzene (Scheme 7a) and the corresponding squared HMO coefficients (cjM)2, which allow one to augment the blind centers without a CH bond (Scheme 7b), prove that more than half of the 7r-spin population p7 is located in the [(HjC Si Si half-shell... 

Trimethyl-2,4,6-tri(3,5-di-tert-butyl-4-hy-droxy benzyl)benzene (lonox330) 774.6 0.918 (25) 44.0... 

Chromatograms in Figure 6 show the separation of tri-methylbenzenes. As it was observed for dialkylbenzenes p -CD complexation not only improves selectivity towards trimethylbenzene isomers, but also works as an organic solvent by lowering their capacity factors. This makes the time of analysis shorter and detectability better (2j ). The improvement in the resolution of trimethyl benzenes due to the OC-CD complexation is not so obvious. 

However, convincing evidence has emerged recently which works against participation of cyclobutadiene intermediates in these reactions. Whitesides and Ehmann (198) have shown that l,2,3-trimethyl-4,5,6-tri(methyl-d3)benzene is not a product in the Co2(CO)b assisted cyclo-trimerization of MeCsCCDa. This evidence establishes that the activity of the catalyst in this system does not depend on the generation of free or metal complexed cyclobutadiene intermediates. 

SYNS l-AMINO-2,4,5-TRlMETHYLBENZENE psi-CUMIDINE NCI-C02299 PSEUDOCUMIDINE l,2,4-TRIMETHYL-5-.3MINOBENZENE 2,4,5-TRI-METHYLANIUN (CZECH) 2,4,5-TRIMETHYL-BENZEN AMINE... 

TMJOOO CAS 1709-70-2 HR 2 1,3,5-TRIMETHYL-2,4,6-TRIS(3,5-DI-tert-BUTYL-4-HYDROXYBENZYL) BENZENE... 

Acetylenes are well known to undergo facile trimerizations to derivatives of benzene in the presence of various transition metal catalysts 23). A number of mechanisms for this process have been considered including the intervention of metal-cyclobutadiene complexes 24). This chemistry, however, was subjected to close examination by Whitesides and Ehmann, who found no evidence for species with cyclobutadiene symmetry 25). Cyclotrimeri-zation of 2-butyne-l,l,l-d3 was studied using chromium(III), cobalt(II), cobalt(O), nickel(O), and titanium complexes. The absence of 1,2,3-trimethyl-4,5,6-tri(methyl-d3) benzene in the benzene products ruled out the intermediacy of cyclobutadiene-metal complexes in the formation of the benzene derivatives. The unusual stability of cyclobutadiene-metal complexes, however, makes them dubious candidates for intermediates in this chemistry. Once formed, it is doubtful that they would undergo sufficiently facile cycloaddition with acetylenes to constitute intermediates along a catalytic route to trimers. 

I33-Trimethyl-2,4,6-tris[3,5-di-ferr-butyl-4-hydroxybenzyr benzene ("Ethyl antioxidant 330). Mol. wt. 775.2, m.p. 244°. 

This procedure is a modification of that published by Pearson et al. A l.S-L two-necked flask equipped with a reflux condenser, magnetic stirrer bar, and surrounded by aluminum foil (to minimize exposure to light) is charged with trimethyl phosphate (Aldrich) (1 L) and dessicator dried (P2Oj) tri-tert-butyl-benzene (Aldrich) (76 g, 0.3 mol). The mixture is then stirred and warmed to 8S°C by means of an oil bath until the hydrocarbon dissolves. The temperature is lowered to 70 °C and bromine (56 g, 18 mL, 0.35 mol) is added rapidly. 

Aminohemi mel I i tene 5-Am i no- 1,2,3-tri methyl -benzene or 3,4,5-Trimethyl anillne(Amino-hemellitol in Ger), H,N "CtH, (CH,),. Ndls, mp ca 75°. Can be prepd by heating sym-m-xylidene hydrochloride with methanol, or by other methods... 

The 2,3,4-tri-O-benzyl derivative (24) may be prepared in 76% yield by catalytic, azeotropic dehydration of D-glucose tribenzyl ether (23) with p-toluenesulfonic acid in benzene.316 (The analogous trimethyl... 

The example given here is derived from 1,3,5-tri(bromomethyl)-2,4,6-trimethyl-benzene (10), as it is significantly easier to prepare than the 2,4,6-triethylbenzene analogue (Figure 1.17). The choice of benzene as a base for the tripod gives a... 

Aromatics Originally meaning fragrant compounds, aromatics are now defined as Benzenes and those compounds which resemble benzene in their chemical behaviour . Simple aromatics contain only one aromatic ring and may be either mono-, di- or tri-substituted, for example, one, two or three hydrogen atoms in benzene can be substituted to form methyl benzene (toluene), dimethyl benzene (xylene) and trimethyl benzene respectively as in Figure 6.2. Aromatic... 

Commercially important di- and polyphenolic stabilizers include 2,2,-methylenebis(6-/ n -butyl-y>-cresol) [85-60-9] (7), l,3,5-trimethyl-2,4,6-tris(3 5 -di-/ 7 -butyl-4-hydroxybenzyl)benzene [1709-70-2] (8), and tetrakis[methylene(3,5-di-/ butyl-4-hydroxyhydrocinnamate)]methane [6685-19-8] (9). 

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