1783-02-4Relevant articles and documents
The mechanism of nitration of 2,4,6-trialkylphenols by nitrogen dioxide in solution
Coombes, Robert G.,Diggle, Andrew W.,Kempsel, Stewart P.
, p. 8557 - 8560 (1993)
The apparent rate of reaction of 2,4,6-trialkylphenols with nitrogen dioxide in solution is that of a 6-nitrocyclohexa-2,4-dien-1-one to 4- nitrocyclohexa-2,5-dien-1-one isomerisation unless the 2- and 6-alkyl groups are sufficiently bulky when the rate limiting stage may involve reaction between the appropriate phenoxy radical and NO2.
THE KINETICS OF THE REACTIONS OF 2,6-DI-t-BUTYL-4-METHYLPHENOL AND 2,4,6-TRIMETHYLPHENOL WITH NITROGEN DIOXIDE IN SOLUTION
Coombes, Robert G.,Diggle, Andrew W.,Kempsell, Stewart P.
, p. 2037 - 2040 (2007/10/02)
The reaction of 2,6-di-t-butyl-4-methylphenol with nitrogen dioxide to form 2,6-di-t-butyl-4-methyl-4-nitrocyclohexa-2,5-dienone has a first order dependence of rate on the concentration of the species N2O4.By contrast the observed rate of the correspondi
ipso Nitration. XXIV. Nitration of 2-methylphenols. Formation and rearrangement of 6-methyl-6-nitrocyclohexa-2,4-dienones
Cross, Gordon G.,Fischer, Alfred,Henderson, George N.,Smyth, Trevor A.
, p. 1446 - 1451 (2007/10/02)
Nitration of o-cresol and some mono-, di-, and trimethyl derivatives in acetic anhydride at -60 deg C gives 6-methyl-6-nitrocyclohexa-2,4-dienones.The dienones are more labile than the isomeric 4-methyl-4-nitrocyclohexa-2,5-dienones and, if the 2-position of the dienone is not blocked, undergo regiospecific rearrangement to 6-nitro-o-cresols. 2,3,6-Trimethyl- and 2,3,5,6-tetramethylphenol also give a 2,5-dienone with nitro attached to a secondary carbon.
ipso-Attack in the Nitration of Aromatic Amines. Part 2. Isolation of Salts and Other Products resulting from ipso-Attack
Helsby, Paul,Ridd, John H.
, p. 311 - 316 (2007/10/02)
In 70percent nitric acid at 0 deg C, NN,2,4,6-pentamethylaniline undergoes ipso-attack at the 4-position to form the relatively stable ipso-intermediate (2); this ion can be precipitated as the hexafluorophosphate.In more aqueous media, the dimethylamino group is displaced by water to form the hexadienone (4).In aqueous nitric acid at 0 deg C, NN,2,4-tetramethyl-6-nitroaniline undergoes both ipso-attack and addition of water to the ring to form the adduct (8); this ion can also be precipitated as the hexafluorophosphate.The reaction of NN,2,6-tetramethyl-4-methoxyaniline with 52 percent nitric acid at 0 deg C also involves displacement of the dimethylamino group and gives finally 2,6-dimethylbenzoquinone.The initial stages of the reactions of the above amines require the presence of nitrous acid and the reactions are inhibited by hydrazine.
Isolation and Further Reactions of Charged Species resulting from ipso-attack in the Nitration of Aromatic Amines
Helsby, Paul,Ridd, John H.
, p. 926 - 927 (2007/10/02)
Charged species resulting from ipso-attack in the nitration of aromatic amines can be precipitated as hexafluorophosphates but the isolation is complicated by addition and substitution reactions involving water in the solvent.
