Aromatic amines alkyl anilines

All lation of Aromatic Amines and Pyridines. Commercially important aromatic amines are aniline [62-53-3] toluidine [26915-12-8], phenylenediamines [25265-76-3], and toluenediamines [25376-45-8] (see Amines, aromatic). The ortho alkylation of these aromatic amines with olefins, alcohols, and dienes to produce more valuable derivatives can be achieved with soHd acid catalysts. For instance, 5-/ f2 butyl-2,4-toluenediamine (C H gN2), which is used for performance polymer appHcations, is produced at 85% selectivity and 84% 2,4-toluenediamine [95-80-7] (2,4-4L)A)... 

Aromatic amines - [ALKYLATION] (Vol 2) - [AMINES - AMINES, AROMATIC - ANILINE AND ITS DERIVATIVES] (Vol 2)... 

Common nomenclature of simple amines involves presenting the name of the alkyl group followed by the word amine (such as propylamine) this type of nomenclature is acceptable in IUPAC for simple amines. In IUPAC nomenclature, the name is based on the longest continuous chain of carbon atoms followed by the suffix -amine (such as 1-propanamine). Substituents on the carbon chain are located by a number substituents on the nitrogen are located with N (such as N-methyl-1-propanamine). The simplest aromatic amine is aniline. 

As in pyrroles, the A-hydrogen in indoles is much more acidic (pAa 16.2) than that of an aromatic amine, say aniline (pAa 30.7). Any very strong base will effect complete conversion of an A-unsubstituted indole into the corresponding indolyl anion, amongst the most convenient being sodium hydride, H-butyllithium, or an alkyl Grignard reagent. 

The aromatic amines, or anilines, are called benzenamines (Section 15-1). For secondary and tertiary anunes, the largest alkyl substituent on nitrogen is chosen as the alkanamine stem, and the other groups are named by using the letter N-, followed by the name of the additional substituent(s). 

A AlI lation. A number of methods are available for preparation of A/-alkyl and A[,A/-dialkyl derivatives of aromatic amines. Passing a mixture of aniline and methanol over a copper—zinc oxide catalyst at 250°C and 101 kPa (1 atm) reportedly gives /V-methylaniline [100-61-8] in 96% yield (1). Heating aniline with methanol under pressure or with excess methanol produces /V, /V-dimethylaniline [121 -69-7] (2,3). 

C-alkylation of secondary and tertiary aromatic amines by hexafluoroacetone or methyl trifluoropyruvate is performed under mild conditions [172] (equation 147) The reaction of phenylhydrazme with hexafluoroacetone leads selectively to the product of the C-hydroxyalkylation at the ortho position of the aromatic ring The change from the para orientation characteristic for anilines is apparently a consequence of a cyclic transition state arising from the initial N hydroxy alky lation at the primary amino group [173] (equation 148)... 

Nearly every substitution of the aromatic ring has been tolerated for the cyclization step using thermal conditions, while acid-promoted conditions limited the functionality utilized. Substituents included halogens, esters, nitriles, nitro, thio-ethers, tertiary amines, alkyl, ethers, acetates, ketals, and amides. Primary and secondary amines are not well tolerated and poor yield resulted in the cyclization containing a free phenol. The Gould-Jacobs reaction has been applied to heterocycles attached and fused to the aniline. 

The reduction of nitrobenzene to aniline is a major industrial process at the heart of the production of polyurethanes, and it is also often used as a marker reaction to compare activities of catalysts [1,2], It can be performed over a variety of catalysts and in a variety of solvents. As well as its main use in polymethanes, aniline is used in a wide range of industries such as dyes, agrochemicals, by further reaction and functionalisation. Reductive alkylation is one such way of functionalising aromatic amines [3, 4], The reaction usually takes place between an amine and a ketone, aldehyde or alcohol. However it is possible to reductively alkylate direct from the nitro precursor to the amine and in this way remove a processing step. In this study we examined the reductive alkylation of nitrobenzene and aniline by 1-hexanol. 

In the previous analysis for the second quadrant amines, there was evidence that the presence of an aromatic ring (BzAM) increased competition with the deactivating intermediate(s) and significantly the amount of DHQ obtained. The study was thus extended to other aromatic amines aniline (AN), 2-ethylaniline (2-ETAN), 3-ethylaniline (3-ETAN) and N-ethylaniline (N-ETAN). These amines are not classified in the literature analysis of amine properties (16), although aniline and pyridine were studied by statistical analysis of their solvent properties and classified in the same sector (16). By analogy, we hypothesize that these model aromatic amines should be classified in the second sector. Thus, they may aid in an understanding of the specific role of the aromatic ring and the effect of an alkyl substituent. 

N-Alkylation of primary aromatic amines increases their nucleophilic character, making them couple much more readily, the introduction of the azo group occurring in the 4-position. Thus, in contrast to aniline, N-methylaniline couples readily and N,N-dimethyl-aniline very readily with simple diazonium salts. Diphenylamine also couples in the 4-position, but less readily than N-methylaniline. 

Aromatic amines (anilines) may become activated in vivo to form reactive amines. These are nucleophiles and may attack DNA, forming covalent modifications. Aromatic nitro compounds can be metabolised to also form reactive amines. A-nitroso compounds result in the alkylation of oxygen sites in DNA bases (0-6 in guanine and 0-4 in thymidine) [8,10]. 

As indicated above, tertiary aromatic amines are directly C-nitrosated. The usual reagents are sodium nitrite and dilute hydrochloric acid, sodium nitrite and glacial acetic acid containing concentrated hydrochloric acid, and nitrite esters with hydrochloric acid [21a, 27]. While tertiary amines with such complex alkyl groups as found in A,A-di(3,5,5-trimethylhexyl)aniline are readily nitrosated [25], of the four A-butyl-A-methylaniline isomers, JV-r-butyl-A-methylaniline does not undergo the reaction, and even the nitroso compounds which did form were only unstable oils [27]. 

The increasing industrial demand for alkylated aromatic amines initiated research to develop heterogeneous catalytic process for the alkylation of aniline and alkyl anilines. 

The procedure has also been applied for the hydroxylation of aromatic amines. Aniline and its /V-alkyl-substimted derivatives show similar behavior under similar conditions to afford the meta-substi tuted aminophenols as the major hydroxylated product.627 Product formation was interpreted by the attack of protonated hydrogen peroxide on the anilinium ion protected by /V-protonation from oxidation or degradation. Indoles, indolines, and tetrahydroquinoline have also been successfully hydroxylated with H202 in HF-SbF5 with the hydroxyl group meta to the nitrogen function.559,628 Hydroxylation of tryptophane and tryptamine derivatives affords pretonine and serotonine derivatives in 42% and 38% yields, respectively.629... 

The activity of some catalytic systems has been studied. For example, Deng has shown that the synthesis of symmetric ureas from aliphatic or aromatic primary amines and C02 can be promoted by catalytic amounts of CsOH in several ILs [128a], Under the working conditions employed (443 K, 6 MPa C02 pressure), the best activity was shown by the system CsOH/BMImCl, whilst the urea yields (up to 98% within 4h, for N,N -dicyclohexylurea) were shown to depend on the amine used. Aromatic amines, such as aniline or p-methoxyaniline, were less reactive than their aliphatic counterparts and afforded the relevant urea in modest yield (27 and 33%, respectively), but only after long reaction times (36 h). In a later study, the same group showed that the synthesis of disubstituted symmetric ureas (RNH)2CO (R = alkyl) from amines and C02 could be promoted also by catalytic... 

Compounds with Reactive Methylene Groups. In this group the coupling components with the greatest industrial importance are the A-acetoacetyl derivatives of aromatic amines (acetoacetarylides) CH3COCH2CONHAr. Anilines substituted by halogen, alkyl, alkoxy, nitro, and acylamino groups are most suitable (e.g., Napthol AS-IRG). 

Dialkylanilines that bear a cationic substituent at one of the alkyl groups are among the most important coupling components of cationic azo dyes. By reaction of iV-ethyl-iV-(2-chloroethyl)aniline or of N-ethyl- N-(2-chlo roethy 1)- w-toluidine with trimethylamine, ammonium salts are obtained that, upon coupling with dia-zotized aromatic amines, yield a large number of valuable dyes for coloring polyacrylonitrile. Red shades with a blue cast are obtained with 2-cyano-4-nitroani-line as the diazo component. 

Many other aliphatic or aromatic amines produce the same reaction. However if N-alkyl (or aryl)2-aniline is made to react with tris-dimethylaminophosphine, tricoordinated phosphorus compounds are obtained. Their analyses and mass spectra show that they are tetramers (5) when the energy of the ionizing electron beam is nearly 70 eV the mass spectra of the oligomers show an intense [M] peak which corresponds to the monomer ion (n = 1) but when the spectra are obtained by field desorption m.s. the molecular ion peak corresponds to a tetramer (n = 4) one sees also smaller peaks for ions n = 3, 2 or 1. 

Emerson and Waters alkylated primary aromatic amines with C2-C7 aliphatic aldehydes and benzaldehyde over Raney Ni in the presence of sodium acetate as a condensing agent and obtained /V-alkylanilincs in 47-65% yields.33 With C2-C5 aldehydes, up to 10% of the tertiary amines were produced, but no tertiary amines were found in the case of heptanal and benzaldehyde. With acetaldehyde in the absence of sodium acetate, aniline was recovered unchanged over platinum oxide and a mixture of amines resulted over Raney Ni, compared to 41 and 58% yields of N-ethylaniline over platinum oxide and Raney Ni (eq. 6.12), respectively, in the presence of sodium acetate. 

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