42887-62-7Relevant articles and documents
Photochemical nitration by tetranitromethane part XXXI. The photochemical reaction of 1,2,3,4-tetramethylbenzene and tetranitromethane
Butts, Craig P.,Eberson, Lennart,Fulton, Karen L.,Hartshorn, Michael P.,Jamieson, Geoffrey B.,Robinson, Ward T.
, p. 735 - 744 (2007/10/03)
Photolysis of the 1,2,3,4-tetramethylbenzene-tetranitromethane charge-transfer complex yields the triad of 1,2,3,4-tetramethylbenzene radical cation, nitrogen dioxide and trinitromethanide ion. Recombination of this triad gives predominantly the epimeric 1,2,3,4-tetramethyl-3-nitro-6-trinitromethylcyclohexa-1,4-dienes 8 and 9, 1,2,3,4-tetramethyl-r-5-nitro-t-6-trinitromethylcyclohexa-1,3-diene (10) and its nitro-alkene cycloaddition product, nitro cycloadduct 11, the 'double adduct' 1,2,3,4-tetramethyl- c-2,c-5-dinitro-t-6-trinitromethylcyclohex-3-en-r-1-ol 12, 2,3,4,5-tetramethyl-1-nitrobenzene (13), and the two products of elimination or rearrangement of labile intermediate adducts, 2,3,4,5-tetramethyl-1-trinitromethylbenzene (7) and 2,3,4-trimethyl-1-nitromethylbenzene (14). Adducts 8-12, and 2,3,4,5-tetramethyl-1-trinitromethylbenzene (7) are formed by initial attack of trinitromethanide ion at a non-methylated ring position in the radical cation of 1,2,3,4-tetramethylbenzene (6), while 2,3,4-trimethyl-1-nitromethylbenzene (14) arises from initial attack of trinitromethanide ion ipso to a 1-(4-)-methyl group in the radical cation 6 + . Adduct formation is substantially suppressed in the photolysis of the 1,2,3,4-tetramethylbenzene-tetranitromethane charge-transfer complex in 1,1,1,3,3,3-hexafluoro-2-propanol, only the adduct elimination product 2,3,4,5-tetramethyl-1-trinitromethylbenzene (7) being formed in addition to the major product, 2,3,4,5-tetramethyl-1-nitrobenzene (13). X-Ray crystal structure determinations are reported for 2,3,4,5-tetramethyl-1-trinitromethylbenzene (7) and adduct 9. Acta Chemica.
Electrophilic Aromatic Substitution. Part 27. Chemical Selectivities Disguised by Mass Diffusion. Part 6. The Kinetics of Nitration in Aqueous Sulphuric Acid of Durene (1,2,4,5-Tetramethylbenzene). Nitrodurene, and Nitroprehnitene (Nitro-1,2,3,4-tetramethylbenzene). A Comparison ...
Manglik, Ajay K.,Moodie, Roy B.,Schofield, Kenneth,Dedeoglu, Erol,Dutly, Andreas,Rys, Paul
, p. 1358 - 1366 (2007/10/02)
Durene (1,2,4,5-tetramethylbenzene) is nitrated in sulphuric acid at the encounter rate.Nitrations of nitrodurene and nitroprehnitene (nitro-1,2,3,4-tetramethylbenzene) are complicated by the formation of nitrous acid, presumably as a consequence of ipso-attack, and subsequent undefinied reactions of this.When an efficient nitrous acide trap is present the complications are removed and the kinetics become straightforward.Although nitrobenzene is 108 times less reactive than benzene in nitration, nitroprehnitene and nitrodurene are only 41 and 20 times less reactive than their respective parent hydrocarbons.These reduced relative reactiviities are a consequence of the fact that prehnitene and durene react at the encounter rate.The low relative reactivity of durene and 3-nitrodurene leads to the formation of some 3,6-dinitrodurene in the nitration of durene, even under the most favourable circumstances, and if mixing is inefficient the dinitro-compound may be the main product.By measuring the yield of 3-nitrodurene, as it varies with acidity, it is possible to determine the amount formed by direct attack at C-3 as distinct from that formed by ipso-attack followed by rearrangement.As a consequence the ratio of positional selectivity between C-3 and C-1 is shown to be 1 : 3.6.Thus, positional selestivity does not disappear.The intrinsic rate constants for nitronium ion nitrations in sulphuric acid of a number of methylnitrobenzenes show an excellent linear correlation with those for nitrations with nitronium hexafluorophosphate in nitromethane deduced by application of a theoretical mixing-reaction model.Differences between the two systems are not large, but appear to be in the direction showing the electrophile in sulphuric acid to be rather more reactive and more selective than in the organic solvent.
