Trisubstituted anilines

The diazotization reaction typically involves an aromatic amine, such as a mono-, di-, or trisubstituted aniline, as a diazo component. Coupling components are also frequently based on aniline or its derivatives. The following examples are thus important diazo components ... 

Product mixture of regioisomers, 1,2,3-and 1,2,5-trisubstituted anilines, ratios varying between 36 64 to and 17 83. 

The Sandmeyer method has been used with di- and trisubstituted anilines to prepare di-4,6,13,14,19,32,38-55 and tri-5,13,19,30,56 substituted isatins. Although -acetamidoaniline and 5-acetamido-2-aminotoluene gave 5-acetamido- and 5-acetamido-7-methylisatin, respectively,30 the use of 4-acetamido-2-aminotoluene and 5-acetamido-2,4-dimethyl-aniline gave the appropriate aminoisatins.30,52 Other examples of hydrolysis during this cyclization are in the conversion of diethyl 5-aminoisophthalate to isatin-4,6-dicarboxylic acid53 and 2-methyl-5-... 

The Sandmeyer method has been used with di- and trisubstituted anilines to prepare and substituted... 

In this review, attention is focused primarily on the oxidation mechanisms under the given conditions, which is the essential topic of interest for organic chemists. Reaction pathways will be outlined if they seem to be well established. However, even small differences in medium properties used by different researchers can lead to serious variations as will be shown in some examples. Anodic oxidation of unsubstituted aniline is discussed in Section II and electrode reactions of /V-substifilled and C-substituted anilines in Sections III and IV, respectively. In the last case, the oxidation of reactants with monosubstituted ring is presented first (para-substituents separately from the effects of ortho- and mefa-substituents), and next the oxidation of di- and trisubstituted anilines. In each part the processes in dipolar aprotic solvents, in particular in acetonitrile (ACN) and /V. /V-dimethylformamide (DMF), are compared with those proceeding in aqueous solutions, chiefly in commonly used acidic media. 

Reduction of anilines to cyclohexylamines over RuOj works successfully on a series of nuclear substituted substrates, at 90-125°C, 8 X 10 kPa, in alcohols or without solvent". Yields of 92% are obtained in the preparation of diamines such as bis(4-aminocyclohexyl) methane, the product being mostly cis,cis and cis,trans isomers . Phenylenediamines are reduced to the 1,3-diamine (91%) or to the 1,4-diamine (88%) over ruthenium-on-alumina in ethanol. The c/j-isomer predominates (70-84%) in a number of solvents and over a range of experimental conditions ". Synthetic advantages can be taken from some side reactions. Hydrogenation of 3,4-diaminobenzoic acid can lead to a mixture of bicyclic lactams that lack an amino substituent . Selective hydrogenation of trisubstituted aniline 9 affords lactame 10, an intermediate in the total synthesis of ibogamine. ... 

Aniline Oxidations. 1,4-Quinones are formed by the reaction of 2,6-disubstituted and 2,3,6-trisubstituted anilines and Fremy s salt. Other ortho or meta methoxy-substituted aromatic amines were converted to the corresponding l,4-quinones and 1,2-quinones. In one case the oxidation intermediate, a quinone imine which subsequently undergoes hydrolysis to the quinone, has been isolated (eq 3). ... 

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