Naphthylamine isomerization

The scope and mechanism of the isomerization of arylamines to methyl-substituted aromatic heterocycles have been studied. Aniline, toluidines, naphthylamines and m-phenylenediamine all gave the corresponding ortho-methyl-substituted aza-aromatics when exposed to high NHj pressure and elevated temperature in the presence of acid catalysts, e.g., zeolites. The yiel of pyridines formed by this process range from low to moderate <95JC(155)268>. 

Nitration of naphthalene-1-sulphonic acid produces two isomeric nitronaphthalenes that have very similar solubilities. It is convenient to reduce the mixture without separation, giving a mixture of l-naphthylamine-8-sulphonic acid (4-44 Peri acid) and 1-naphthylamine-5-sulphonic acid (4.45 Laurent s acid), as in Scheme 4-29. These two... 

Let us now turn to compounds with more than one benzenoid ring. The first species are the isomeric a- and /J-naphthylamincs, 18a and 18b. The archival enthalpies of formation are found to be 157.6 6.9 and 133.8 5.1 kJmol-1. The 24 9 kJmol-1 difference of these two numbers is incompatible with the near-zero difference of the enthalpies of formation for the isomeric naphthols, methyl- and bromonaphthalenes32. Which or either naphthylamine has the correct enthalpy of formation The gas-phase enthalpies of formation of the naphthols differ from their single benzene ring analog, phenol, by 66 kJmol-1 in close agreement with the difference between the methylnaphthalenes and toluene, 63, and between the brominated and parent hydrocarbons, 69 6 and 68 2 kJmol-1 respectively. That is, it is plausibly asserted33 that the difference quantities 17 are nearly constant and equal. 

What about jr-electron donor substituents on nitrosoarenes other than dimethylamino Pedley gives us the enthalpies of formation for three hydroxy derivatives the isomeric 4-nitroso-l-naphthol, 2-nitroso-l-naphthol and l-nitroso-2-naphthol, species 45-47 respectively. Of the three species, only the first cannot have an intramolecular hydrogen bond. By analogy to nitrophenols75 — there being no thermochemical data for the more related and hence relevant nitronaphthols—we expect that species 46 would be less stable than 45. After all, gaseous 2-nitrophenol is ca 20 kJ mol 1 less stable than its 4-isomer. We recall from the discussion of the isomeric naphthylamines that 1- and 2-naphthol are of almost identical stability. This suggests that species 46 and 47 should be of comparable stability. Both expectations are sorely violated by the literature results the enthalpies of formation of species 45, 46 and 47 increase in the order —20.3 4.9, —5.4 6.2 and 36.1 4.7 kJmol-1 respectively. If there is experimental error, where does the error lie ... 

Nitration via diazotisation has been extensively used for the synthesis of isomeric dinitronaphthalenes. Ward and co-workers used nitration via diazotisation to prepare 3,3, 4,4 -tetranitrobiphenyl from 3,3 -dinitrobenzidine, and 3,4,5-trinitrotoluene from 3,5-dinitro-4-toluidine. Ward and Hardy " prepared 1,4,6-trinitronaphthalene from 4,7-dinitro-1-naphthylamine. Korner and Contardi used the nitrate salts of aryldiazonium compounds for the synthesis of polynitro derivatives of benzene " and toluene. " " Accordingly,... 

Ullmann and Fetvadjian reported the modification which made the synthesis more generally useful, when they heated together equimolar amounts of an aromatic amine and a phenol with paraformaldehyde or with benzaldehyde, thus making it possible to obtain unsymmetrical acridines (03CB1027). Thus, from 2-naphthol and 1-naphthylamine they obtained dibenzo[c,/]acridine (613), and from 2-naphthol and 2-naphthylamine dibenzo[c,fi]acridine (614). In a similar manner, from 1-aminoacridine and the two naph-thols are obtained the benzo [a]- and benzo[c]-naphtho[2,3-fi]acridines (615) and (616), and from 2-aminoacridine and the naphthols the benzo[a]- and benzo[c]-naphtho[2,3-/]acridines (617) and (618) (69JCS(C)1337). The isomeric benzofa]- and benzo[c]-... 

In the reaction with a less basic amine such as aniline, mixtures of naphthylamines 153 and isoquinolinium salts 152 were obtained (71KGS1437 88UP2). The alternative pathway of formation of naphthylamines 153 from isoquinolinium salts 152 by isomeric recyclization (81T3425) is completely excluded, since model experiments with isoquinolinium salts showed no reaction under the conditions of synthesis of naphthylamines 153. 

Although not strictly an arylated aniline but rather a benzannelated species, the two isomeric naphthylamines are the simplest polynuclear aromatic hydrocarbon counterparts of aniline. Unfortunately, they are the only such examples with enthalpy of formation data known to the authors. No less than five sets of measurements23,44 - 47 with a range of 29 kJmol-1 have been reported for the enthalpy of combustion, and thus of formation, of 1-naphthylamine. Likewise, for the enthalpy of combustion of 2-naphthylamine... 

Diels-Alder adducts (e.g., 81-84) have been prepared from N-substituted pyrroles with tetrafluoro- and tetrachlorobenzyne.55-66,69,70 These adducts are less readily isomerized to naphthylamine derivatives and less prone to react further with benzyne. A minor product of the reaction of tetrachlorobenzyne with iV-tm-butylpyrrole is the 1,2-cycloadduct 85 (2%), for which... 

The yield of 1-naphthylamine decreases as the temperature is lowered. In contrast, the yield of 9 increases steadily on cooling and reaches a maximum between 213 and 195 K (Table 5). A mixture of the isomeric diamines 9 and 10 is obtained at lower temperature (173-203 K). However, upon further cooling to 113 or 77 K, the yields of adducts are tremendously reduced and azonaphthalene predominates. The photochemical reactions run between 173 and 77 K used a solvent mixture of 4 1 isopentane/cyclopentane which is much less viscous than methylcyclohexane at these temperatures. 

Naphthylaminesulphonic Acids.—A large number of isomeric sulphonic acids derived from a- and /3-naphthylamine are known and several of them are extensively used in the dye-stuff industry. 

Naphthylamine can take up four atoms of H to form two isomeric tetrahydro-naphthylamines I and II which have the Kekule formulae ... 

A novel meridional bicyclometallation was achieved by methane extrusion from [Fe(CH3)2(PMe3)4] with A -benzylidene-l-naphthylamine and (l-naphthyl)(2-pyridyl)ethene. In the crystal structures of isomeric 131 and 132, the iron center bears three meridional PMe3 ligands. C-H activation of aromatic imines in the presence of [Fe(CH3)2(PMe3)4] or [Fe(PMe3)4] led to the orthometallated methyl and hydride compounds 133 and 134, respectively. ... 

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