Reducing agents alkylamine

It is well known that quinizarin (22) is alkylaminated in air to give a mixture of l-alkylamino-4-hydroxyanthraquinone (23), l,4-bis(alkylamino)-anthraquinone (24), and 2-alkylaminoquinizarin (25) (Scheme 7). The reaction conditions affect the ratio of these products. In a nitrogen atmosphere, or in the presence of sodium dithionite as reducing agent, the main amination product is 24. The solvent effects of the reaction of leuco... 

In the presence of excess monoalkylamine, carbonyl compounds in aqueous solution are in equilibrium with the corresponding imine. In most cases these imines cannot be isolated but they are reduced at a less negative potential than the carbonyl compound. Selective reduction of such equilibrium mixtures is a useful route to alkylamines from ketones in yields of 70-90%. The process fails with hindered ketones such as camphor and with bulky amines such as fert.-butyl amine. Overall the reaction has advantages of lower costs and simpler work-up compared to the use of cyanoborohydride reducing agents. In the electrochemical reaction, protonation of carbanion intermediates occurs from the more hindered side and where two isomeric products are fomied, the least hindered amine predominates [193]. 

Arylamines are prepared by nitration of an aromatic ring followed by reduction. Alkylamines are prepared by Sn2 reaction of ammonia or an amine with an alkyl halide as well as by a number of reductive methods, including LiAlH4 reduction of amides and nitriles. Also important is the reductive amination reaction in which an aldehyde or ketone is treated with an amine in the presence of a reducing agent. 

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