1.3.5- Tris benzen

A solution of sodium methoxide (80 mmol) in methanol (40 mL) is added to silica gel (2.7 g, 45 mmol) followed by a solution of catechol (13.2 g, 120 mmol) in methanol (40 mL). The resulting mixture is stirred and heated under reflux for 18 h. The methanol is then evaporated and the solid residue washed with ether. The black sohd is dissolved in THF (400 mL) and the resulting solution is heated for 1 h in the presence of charcoal. After filtration and evaporation of the solvent the sodium tris(benzene-l,2-diolato)silicate 80 is isolated as a white powder (12.53 g, 70% Scheme 2.20) [93]. 

Let s try benzene, C6H6. Benzene is neither tetrahedral nor octahedral. 

C. Reactivity of Tris(benzene-l,2-diolato) Complexes of Silicon. 1271... 

In contrast to the well-established chemistry of the tris [benzene-1,2-diolato(2-)]silicate dianion (including derivatives with substituted ligands), the chemistry of the related tris[ethane-l,2-diolato(2-)]silicate dianion is significantly less well explored. To the best of our knowledge,... 

Figure 13 The structure of the tris(benzene-lf2-diolato)arsenate(y) anion, showing the absolute configuration (Reproduced by permission from Acta Cryst., 1972, B28, 3446)...

Cowie M, Bennett MJ (1976) Trigonal-prismatic vs. octahedral coordination in a series of tris (benzene-l,2-dithiolato) complexes. 1. Crystal and molecular structure of tris(benzene-l,2-dithiolato)molybdenum(VI), Mo(S2CsH4)3. Inorg Chem 15 1584-1589. doi I0.I02I/... 

The extremely unstable mono-77-cyclopentadienyltitanium tri(benzene-thiolate) has also been reported, ... 

An unusual oxidation of phosphines involving water as the oxygen source and tris(benzene-l,2-dithiolate)molybdenum(vi) as the oxidant was also described. 

C74H79B10N2P3RUS, Dihydrido(dimethylsulfidodia2odecaborane)tris(tri-phenylphosphine)ruthenium tris(benzene), 43B, 1344 C7 6H60MO2N8, Tetrakis(N,N diphenylbenzamidinato)dimolybdenum(II), 41B, 1101... 

C1BH12M0S6, Tris(benzene-1,2-dithiolato)molybdenum(VI), 42B, 942 ClbHi2N2PdS2, Bis(8"mercaptoquinolinato)palladium, 39B, 824 ClbHi2N2PtS2 f Bis(8-mercaptoquinolinato)platinum, 39B, 824 ClbHj 3O9OS3PS2 f (M"Hydrido)-(M"dithioformato)-bis(tricarbonyl-osmium)-tricarbonyl(dimethylphenylphosphine)osmium, 46B, 1212 ClbHi5Cl2HgPSe, Triphenylphosphine selenide mercury(II) chloride, 40B, 1128... 

C26H3sN2S6Zr, Bis(tetramethylammonium) tris(benzene-1,2-dithiolato)-zirconate(IV), 42B, 947... 

The objective of chemical safety testing is to prevent the introduction into the environment of chemicals that represent a significant health hazard to humans or to the immediate environment on which maintenance of the human species depends. For chemicals that must remain in the environment for one reason or another, safety testing can be used to establish a safe or tolerable exposure level. The potential benefit of test results from evaluations for genotoxicity applied to human health considerations can be substantiated by the early indications of genotoxic activity for vinyl chloride, tris-(2,3-dibromo-propyl) phosphate (TRIS), benzene, hycanthone, and the Japanese food additive 2-(2-furyl)-3-(5-nitrofuryl)acrylamide(AF-2). In some of these cases, mutagenic data were available before the chemicals were identified as animal carcinogens. 

BBC = 4,4, 4"-(benzene-l,3,5-triyl-tris (benzene-4,1-diyl)) tribenzoate BTB = 4,4, 4"-Benzene-1,3,5-triyltribenzoate CSD = Cambridge Structmal Database ... 

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. 

When completed, the solution is merely dumped into 1L of dH20 and extracted 3 x lOOmL Et20 or DCM or benzene. BUT when that solution hits the solvent, the biggest, ugliest emulsion Strike has ever hypothesized occurs. It is wicked The chemists can try all the usual tricks to get rid of that bitch, but when it comes down to it, there is only one way that works. The chemist is going to have to extract with hundreds upon hundreds of mLs of solvent. The idea here is to saturate both the aqueous and emulsion layer with so much solvent that a separate solvent layer can form. Once saturated, the entire mix can then be properly extracted. 

Speed manufacturers need only look at the molecules and imagine them without those extra OHs or methylenedioxy ring structures attached to the benzene core. These particular pathways are, however, more uniquely suited for X precursor production because they take advantage of the hindrance that methylenedioxy ring structures and OHs provide on one side of the benzene core. This helps to better assure that mono chloromethylations or bro-minations will occur whereas di- and tri-substitutions are possible on a naked benzene molecule which speed chemists are going to be using (please don t ask). 

Monosubstitution of acetylene itself is not easy. Therefore, trimethylsilyl-acetylene (297)[ 202-206] is used as a protected acetylene. The coupling reaction of trimethylsilylacetylene (297) proceeds most efficiently in piperidine as a solvent[207]. After the coupling, the silyl group is removed by treatment with fluoride anion. Hexabromobenzene undergoes complete hexasubstitution with trimethylsilylacetylene to form hexaethynylbenzene (298) after desilylation in total yield of 28% for the six reactions[208,209]. The product was converted into tris(benzocyclobutadieno)benzene (299). Similarly, hexabutadiynylben-zene was prepared[210j. 

On the other hand, the halohydrin (chloro and bromo) 908 is converted into a ketone via oxidative addition and //-elimination in boiling benzene with catalysis by Pd(OAc)2 and tri(o-tolyl)phosphine in the presence of K2C03[765,766],... 

How do the charges on the ring carbons of toluene and (tri fluoromethyl)benzene relate to the regioselectivity of nitration" ... 

---