Related to Aniline

The structures of many monocyclic aromatic compounds have little in common the same is often the case for their biological activities. They are consequently grouped here on the basis of some shared structural element rather than biological activity. The three compounds that follow have in common a nitrogen atom attached to the benzene ring. 

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Compounds related to aniline, either directly or by oxidation, and to nitrobenzene by reduction, are numerous and important. When nitrobenzene is reduced in the presence of hydrochloric acid by tin or iron, the product is aniline (colorless liquid in die presence of water by zinc, the product is phenylhydroxylamine (white solid) in the presence of methyl alcohol by sodium alcoholate 01 by magnesium plus ammonium chloride solution, the product is azoxybenzene (pale yellow solid) by sodium stannitc, or by water plus sodium amalgam, the product is azobcnzcnc (red solid) in the presence of sodium hydroxide solution by zinc, the product is hydrazobenzene (pale yellow solid). The behavior of other nitrocompounds is similar to that of nitrobenzene. 

Aniline Dyes.—Aniline and many of its derivatives, also many related amino derivatives of both benzene and naphthalene hydrocarbons, are of great technical importance in the manufacture of dyes. As the first synthetic dye, mauve, was made from aniline the name aniline dyes is often used synonymous with coal tar dyes for all synthetic dyestuffs, though, as we shall find, there are several groups, some of which are in no sense related to aniline. The dyestuffs and the intermediate products connected with their preparation will be referred to as we come to each compound. 

This compound is known as sulphanilic acid. It may also be considered as an amino aderivative of benzene sulphonic acid, i.e.j para-amino benzene sulphonic acid. Its name, sulphanilic acid, is in agreement with its relation to aniline and sulphuric acid. It is distinctly different from sulphonic acids of the hydrocarbons in being difficultly soluble in cold water. As we shall see later, it is of great importance in the preparation of dyes. It is a crystalline compound soluble in alkalies as the alkali salt, but is precipitated as the free acid on acidifying the solution of the salt. 

Aminopyridines are similar to hydroxypyridines in that the 2- and 4-aminopyridines can exist in several forms. 3-Aminopyridine is considered as an aromatic amine related to aniline and behaves so on hydrogenation. Nienburg (89) found that uptake of hydrogen stopped sharply with the absorption of three molar equivalents. 3-Amino-piperidine was obtained in good yield. Another investigation confirmed his results (90). 

Show how oxidation of aniline by a sequence related to Eq. (1) might lead to the brilliant red-purple dye "pseudomauveine," which has a structure related to Aniline Black. 

These relate to aniline and its derivatives, and aim at preparing the most important dyes of the aniline series. Although the reactions which take place in the cell have not as yet been explained, the researches form valuable material for consideration. Goppels-roeder has gathered the technical results in a small pamphlet Farbelektrochemische Mitteilungen (Muhlhausen, 1889). 

Other terms relating to physical properties include viscosity refractive index pour point, ie, the lowest temperature at which the oil flows flash point, ie, the temperature at which the oil ignites and aniline point, ie, the minimum temperature at which equal volumes of oil and aniline are completely miscible. These are determined under defined conditions estabHshed by ASTM. 

Numerous dyes structurally related to the safranines, such as the eurodines, e.g. (141), the indulines, e.g. (142), the nigrosines (143) and aniline black, a pigment of unknown structure used in the printing industry, are well known and a detailed account of their chemistry and applications has been presented (57HC(ll)l). 

The rate of reaction of a series of nucleophiles with a single substrate is related to the basicity when the nucleophilic atom is the same and the nucleophiles are closely related in chemical type. Thus, although the rates parallel the basicities of anilines (Tables VII and VIII) as a class and of pyridine bases (Tables VII and VIII) as a class, the less basic anilines are much more reactive. This difference in reactivity is based on a lower energy of activation as is the reactivity sequence piperidine > ammonia > aniline. Further relationships among the nucleophiles found in this work are morpholine vs. piperidine (Table III) methoxide vs. 4-nitrophenoxide (Table II) and alkoxides vs. piperidine (Tables II, III, and VIII). Hydrogen bonding in the transition state and acid catalysis increase the rates of reaction of anilines. Reaction rates of the pyridine bases are decreased by steric hindrance between their alpha hydrogens and the substituents or... 

A compound closely related to classical adrenergic agonists in which the para hydroxy function is however replaced by an amino group has been investigated for its activity as a growth promoter in domestic animals. Acylation of the aniline derivative 26 with chloracetyl chloride will afford acetophenone 27 the amino-ketone 28 is obtained on reaction with isopropylamine. Removal of the protecting group (29) followed by reduction of the ketone affords cimaterol (30) 5J. 

Closely related to the use of rhodium catalysts for the hydrogenation of phenols is their use in the reduction of anilines. The procedure gives details for the preparation of the catalyst and its use to carry out the low-pressure reduction of /j-aminobenzoic acid. Then, as in the preceding experiment, advantage is taken of the formation of a cyclic product to carry out the separation of a mixture of cis and trans cyclohexyl isomers. 

Interestingly, a substance somewhat closely related to flunixin, triflocin (30), is a diuretic rather than an antiinflammatory agent. It can be prepared by nucleophilic aromatic displacement on 4-chloronicotinic acid (29) with m-trifluoromethyl-aniline.8... 

Although geneologically related to indoles, the dihydroindoles behave chemically rather like alkyl anilines. When diphenylamine reacts with chloro-propionyl chloride, amide 40 results this in turn readily cyclizes to oxindole 41. Sodium hydride followed by 2-chloroethyldimethylamine alkylates the 3-position (possibly through an intermediate aziridinium ion) partial demethylation is accomplished by refluxing with ethylchiorocarbonate, followed by hydrolysis of the intermediate carbamate to give indolinone 42, the antidepressant amedalin Repetition of this sequence on the chloropropyl homologue, followed by reduction of the appropriate indolinone produces dihydroindole 43, daledalin, which also has antidepressant activity. ... 

Closely related to the 1,3,2-dithiazolyl radicals are the isomeric 1,2,3-dithiazolyl radicals. The benzo-fused derivatives were originally prepared by Herz in 192276 from the reaction of aniline and its derivatives with an excess of S2C12 (Scheme 10). Almost invariably the aromatic ring becomes substituted by chlorine para to the amine N atom. 

There are large species differences in the response of hemoglobin to the administration of aniline. Differences appear to be related to the rate of metabo... 

The kinetic behaviour of anionic dyes on amide fibres tends to be much more closely related to molecular size and hydrophilic-lipophilic balance. Thus within a related series of dye structures it is possible to discern more specific relationships. For example, in the series of p-substituted aniline—>R acid dyes (3.91 R = H, methyl, n-butyl or n-dodecyl) the logarithm of the rate of dyeing on wool is inversely proportional to the molecular volume [110]. 

Three major approaches have been followed to provide reactive dyes in this important sector. One category is closely related to the reddish blue monoazo 1 1 copper complexes already described (section 7.5.8). To provide the higher substantivity and deeper intensity for build-up to navy blue shades, a second unmetallised azo grouping is introduced. As with the brown dyes, the A—>M—>E pattern is adopted for their synthesis. Component A is normally a sulphonated aniline, M an aminophenol or aminocresol and E a sulphonated naphthol or aminonaphthol. The reactive system (Z) is usually, but not invariably, located on the E component and the copper atom always coordinates with an o,o -dihydroxyazo grouping provided by the M and E components (7.109). 

A second similar synthesis, due to Doebner and Miller, leads to the formation of substituted quinolines. The simplest example is the production of quinaldine from aniline and paraldehyde by heating with concentrated hydrochloric acid. The course of the reaction is closely related to that of the Skraup synthesis by route II. There the aniline reacts with acrolein, here with crotonaldehyde, which is easily formed under the conditions which prevail ... 

The first acidity measurement of aniline was reported by McEwen122. He assigned an ion-pair pK of 27 to aniline in benzene in relation to MeOH in benzene, which was assumed to have an ion-pair pKa of 16. Acidities of a number of substituted anilines were measured by means of the H method in H2O-DMSO mixture123, and by NMR124, calorimetric125 and electrochemical126 methods in liquid ammonia at —31 °C. 

Amino groups may act not only as proton acceptor, but also as proton donor. Acidic N—H protons interact with basic solvents. In these cases an ortho-nitro group in an aniline system competes with the solvent by an internal hydrogen bond66, as depicted in 12. The stretching frequencies (by IR spectra in carbon tetrachloride) of vnh of complexes between A-methylaniline or diphenylamine (and some nitro-anilines66) and solvents depend on the proton accepting ability of the solvent (which is a moderate base)67. The frequency shifts are linearly related to the solvent s donor number (DN)3. 

Reductions at noble metal electrodes in acidic protic media often form adsorbed hydrogen, which is the actual reductant. For example, reduction of nitrobenzene at a Pd/C electrode in acetic acid-methanol mixtures affords aniline via adsorbed hydrogen28. This reaction is more closely related to catalytic hydrogenation of nitro groups than to the... 

Kamikawa et al. chose the first option to generate the benthocyanin skeleton [91]. To begin with, 100 and aniline 126 are transformed into o-nitrodi-phenylamine 127 by intermolecular N-arylation. Reduction of the nitro group and selective bromination produces 128, and this time an intramolecular Buch-wald-Hartwig reaction is used to derive a mixture of the desired phenazine 129 and the elimination product 130. The fundamental problem with this approach relates to the selective introduction of the halogen substituent that is required for the intramolecular N-arylation. 

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