Transamination amine exchange reactions

The terms transamination and amine exchange reactions denote reactions between ammonia and an amine, or between two amines, in which formally the amino group of one amine is replaced by that of another, e.g.  

In this type of reaction, when heated in the presence of acid catalysts (hydrochloric, phosphoric, or / -toluenesulfonic acid), primary aromatic amines often condense smoothly with loss of ammonia to afford diamines. Diphenyl-amine, for example, can be obtained by heating aniline and aniline hydrochloride for 20 hours at 230°/6 atm.355b 

A-Phenyl-l-naphthylamine 355e This amine, which cannot be prepared smoothly by the Bucherer reaction, is obtained as follows. 1-Napthylamine (143 g), aniline (175 g), and sulfanilic acid (3 g) are heated for 40-48 h under reflux in a flask fitted with a thermometer and a long air-condenser. Ammonia is evolved and the boiling point of the mixture rises from about 195° to 215°. Then, on fractionation in a vacuum, aniline (80-85 g) distils at 70°/12 mm, followed with bumping an dfoaming by an intermediate fraction (8-10 g) that contains a little A-phenyl-1 -naphthylamine. The bulk of the latter (190-195 g) boils at 212 to 216°/12 mm the residue distils up to 225°/12 mm. The total yield is 91 % (about 200 g) of colorless needles, m.p. 62° (from a little ethanol). 

Good yields of iV-aryl-l-naphthylamines are also obtained by using catalytic amounts of iodine with, e.g., 1-naphthylamine and aniline, the toluidines, m- and /7-chloroaniline, o- and /j-anisidine,1045 2,3- or 3,4-dimethylaniline.1122 Di-(2-naphthylamine) is obtained almost quantitatively when 2-naphthyl-amine is heated for 4 hours at 230° in the presence of 0.5-1.0% of iodine, and 4,4 -dihydroxydiphenylamine in 70% yield from / -aminophenol under similar conditions.1045 

2 -Biphenyldiamine is converted almost quantitatively into carbazole when heated with phosphoric acid.1123 

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Transamination is a reaction catalyzed by a family of enzymes called transaminases, which results in the exchange of an amine group of an amino acid with a ketone or a... 

Transamination reactions are occasionally used as an adjunct to the addition reactions described in this section. Aniline and /3-di-ethylaminopropionitrile (as hydrochloride) undergo amine exchange at 140-150° to give )8-anilinopropionitrile (reaction 83) 1 . These... 

Transamination, a type of protonic-acid cleavage, yields amine upon exchange with the amide moiety of a nonmetal or metal amide. These reactions are used to prepare amides or imides. The amine formed is of incidental interest, e.g. ... 

Also in the mid-1994, Buchwald and coworkers developed a means to significantly expand the scope of the Migita reaction through an in situ transamination protocol that exchanged the dimethylamino group of BusSnNMea with various amines [29], This allowed access to a broader array of substituted aniline derivatives (Scheme 1). 

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