Benzene hexakis

In the early work, benzene formed the basis of a variety of multi-armed structures. Analogs bearing from 2—6 arms were prepared and compared for cation binding ability. The only indication of mode of synthesis for the hexa-substituted benzene derivative is that it was obtained on reaction of benzene-hexakis(methanethiol) and l-bromo-3,6,9-trioxatridecane . The reaction is illustrated in Eq. (7.6), below, devoid of reaction conditions and yields which were not specified. 

The phenomenon of increasing ability to form a mesophase as a function of amphi-philicity was also observed when the benzene hexakis(thioethers) 43 were oxidized into their hexakis(sulfones) 44 [142-144] (Fig. 29). In contrast to the nonliquid crystalline thioether series 43, the radial-polar hexasulfones 44 with chains containing between 7 and 15 carbon atoms exhibit a columnar hexagonal type of mesophase established by various methods, including X-ray diffractometry [142-144]. Their lyotropic mesomorphic behavior is also of interest and currently under investigation [145]. 

Inositols, ie, hexaliydrobenzenehexols, are sugars that have received increasing study and are useful in the treatment of a wide variety of human disorders, including vascular disease, cancer, cirrhosis of the Hver, frostbite, and muscular dystrophy (269). Myoinositol esters prepared by reaction with lower fatty acid anhydrides are useful as Hver medicines and nonionic surfactants the aluminum and ammonium salts of inositol hexasulfate are useful anticancer agents (270). Tetraarjloxybenzoquinones are intermediates in the preparation of dioxazine dyes (266,271). The synthesis of hexakis(aryloxy)benzenes has also beenpubUshed (272). 

Perfluorotetramethylthiadiphosphanorbornadiene and bis(trifluoromethyl) thiadiphosphole can be prepared by thermolysis of an adduct of methanol and hexakis(trifluoromethyl)-l,4-diphosphabarrelene with sulfur [113] (equation 23) Pyrolysis of the adduct of hexafluorinated Dewar benzene and phenyl azide results in ring expansion giving azepine, which photochemically yields an intramolecular 2-1-2 adduct, a good dienophile for the Diels-Alder reaction [114, //5] (equation 24) Thermolysis of fluonnated derivatives of 1,5-diazabicyclo-... 

When uradiated, fluonnated isomers of Dewar benzene yield pnsmane derivatives that rearrange thermally to benzene Photolysis of hexakis(mfluororaethyl)benzvalene ozonide gives tetrakis(tnfluoromethyl)cyclobutadiene and its dimer [J47]... 

Benzene reacted with excess 3 in the presence of aluminum chloride at room temperature for 4 h to give peralkylated product," hexakis[2-(methyldichloro-sily I )ethyljbenzcne (4a) and other alkylated products pentakisl2-(mcthyldichloro-silyl)ethyl]benzenc (4b), tetrakis 2-(methyldichlorosilyl)ethyljbenzene (4c), tris 2-(methyldichlorosilyl)ethyl]benzene(4cl), and bis 2-(methyldichlorosilyl)ethylJ-benzene (4e) (Eq. (6)). The product distributions were plotted against mole ratios of 3/benzene in Fig. I. 

To prepare multifunctionalized symmetric organosilicon compounds by the polyalkylation of benzene. (2-chloroethyi)trichlorosilane and (3-chloropropyl)tri-chlorosilane were reacted with benzene. Polyalkylations of benzene with (2-chloroethyl)silane and (3-chloropropyl)silane were carried out in the presence of aluminum chloride catalyst at a reaction temperature of 80 C. The reaction of benzene with excess (2-chloroethyI )trichlorosilanes afforded pcralkylated product, hexakis(2-(trichlorosilyl)ethyl)benzene in good yield (70%). ... 

The reaction of benzene with excess (3-chloropropyl)trichlorosilane afforded peralkylated product, hexakis(3-(trichlorosilyl)propyl)benzene. in moderate yield... 

Hexa(oligophenyl)benzenes (e. g. 31 or 33) present one possible approach to the realization of this aim. Two efficient synthetic routes have been elaborated for the preparation of hexa(terphenyl)- and hexa(quaterphenyl)benzene. The first, involving palladium-catalyzed trimerization of diarylacetylenes [54] as the key step, was demonstrated by the synthesis of a hexakis-alkylated hexa(terphenyl)benzene derivative 31 from the corresponding bis(terphenyl) acetylene (32). The peripheral tert-alkyl substituents serve to solubilize the molecule. 

The first pyrrolylphosphazenes were apparently prepared by McBee and coworkers in 1960, and although the work was never documented in the chemical literature, hexakis-(pyrrolyl)cyclotriphosphazene (1) and octakis-(pyrrolyl)cyclotetraphosphazene were described in a Technical Report of the Defense Technical Information Center.19 Compound 1 was reported to be produced in 26% yield from the interaction of hexachlorocyclotriphosphazene [(NPC 2)3] with excess potassium pyrrolide in refluxing benzene over a 24 hour period. Lithium pyrrolide and pyrrolyl magnesium bromide were found to be unsatisfactory reagents for the preparation of 1. 

Coordination studies of acyclic thioether ligands to silver(I) centers has also been studied. Poly(alkylthio)aromatic systems have been used to form supramolecular silver(I) compounds. With the ligand 2,3,5,6-tetrakis(isopropylthio)benzoquinone the compound has a linear chain structure in which silver(I) has a tetrahedral coordination.1156 A similar structure has the compound with the hexakis(methylthio)benzene,1157 but with the hexakis(tolylthio)benzene the silver... 

Figure 6.10 Chiral hexakis-porphyrinato benzene compound 66, which possesses propellerlike structure and can self-assemble to form helical arrays.

Neutral hexakis(methylsulfonyl)benzene (see Scheme 6.23) adopts a chair conformation. On the contrary, the tube conformer appears to be inherent in the corresponding anion-radical. The methylsulfonyl fragments at positions 1 and 4 of the bent benzene ring are nonequivalent. Moreover, one methylsulfonyl moiety is nonequivalent to all of the other five (Fabre et al. 2002). Scheme 6.23 depicts an intuitively constructed picture. Localization of spin-charge density within one methylsulfonyl group causes the attraction of the other from position 4. This makes the tube conformation the most stable in the case of hexakis(methylsulfonyl)benzene anion-radical. 

When benzene reacts with a six-fold excess of Ic in the presence of aluminum chloride at room temperature, the peralkylated product, hexakis[2-(di-chloromethylsilyl)ethyl]benzene is obtained as the major component along with other lower polyalkylated products pentakis-, tetrakis-, tris-, and bis[2-(di-chloromethylsilyl)ethyl]benzene. 

Gilbert and Voreck synthesized hexakis(azidomethyl)benzene (HAB) (45) from the reaction of hexakis(bromomethyl)benzene (44) with sodium azide in DMF. This azide has been comprehensively characterized for physical, thermochemical and explosive properties and stability. HAB is a thermally and hydrolytically stable solid and not highly sensitive to shock, friction or electrostatic charge but is sensitive to some types of impact. It shows preliminary... 

The chair conformation of the 1,4-dioxane ring is also preserved in the channel of the hexakis(/3-naphthylthio)benzene-l,4-dioxane host-guest complex (82TL4131). 

In the group of Sekiguchi, the dilithiated derivatives of tetrakis- and hexakis(trimethyl-silyl)benzene 226 and 228 in Schemes 78 and 79, respectively, have been synthesized by the reaction of the parent compounds with an excess of metallic lithium in coordinating solvents at room temperature. Both molecular structures in the solid state were cleared up by X-ray structural analysis (Figures 29 and 30) . 

Note 1 Examples are hexakis(acyloxy)benzenes (a), hexakis(acyloxy)- and... 

Hexakis(benzylthio)benzene acts as a rather efficient electron donor. The ESR spectrum obtained with in situ electrolysis indicates a pattern corresponding to the twelve equivalent protons in the benzyl positions. However, cyclovoltammet-ric measurements reveal that the radical cation exists in a complicated equilibrium with the dication and the parent neutral precursor53. Radical ions generated from C60 have been the subject of several publications and discussions within the last years. Several authors have postulated that C6o + can be observed in solid C60. However it could be demonstrated that this signal has to be ascribed to C6a peroxide or its decomposition products54. 

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