Tertiary amines nitrogen hydrides

Excellent procedures are available for the preparation of primary, secondary, and tertiary amines by the reduction of a variety of nitrogen compounds. Primary amines can be obtained by hydrogenation or by lithium aluminum hydride reduction of nitro compounds, azides, oximes, imines, nitriles, or unsubstituted amides [all possible with H2 over a metal catalyst (Pt or Ni) or with LiAlH4] ... 

Amides also undergo two successive additions of hydride ion when they react with LiAlH4. The product of the reaction is an amine. Primary, secondary, or tertiary amines can be formed, depending on the number of substituents bonded to the nitrogen... 

Aziridination of unsaturated ketones can be achieved directly using sodium hydride in conjunction with iV,)V -diammo-l,4-diazoniabicyclo[2.2.2]octane dinitrate (eq 41). This reaction proceeds through a nitrogen-nitrogen ylide. The yUde undergoes Michael addition followed by cyclization of the resulting enolate and expulsion of the tertiary amine. 

Amides also undergo two successive additions of hydride ion when they react with LiAlH4. Overall, the reaction converts a carbonyl group into a methylene (CH2) group, so the product of the reaction is an amine. Primary, secondary, or tertiary amines can be formed, depending on the number of substituents bonded to the nitrogen of the amide. (Notice that H2O rather than H30 is used in the second step of the reaction. If H30 were used, the product would be an ammonium ion rather than an amine.)... 

Proposed mechanism for the Pd/C-catalyzed oxidative synthesis of 2-substituted benzimidazoles was depicted in Scheme 14.11. The initial step seems to be the insertion of palladium into a C-H adjacent to the nitrogen, leading to a highly active intermediate complex of an iminium ion. The proposed catalytic cycle involves the removal of a hydride from tertiary amine by a metal catalyst to form (putative) oxidized iminium cation species, which undergoes a transamination reaction with o-phenylenediamine to generate intermediate imine, with generation of Imol equivalent of H2. Subsequent formation of... 

Stofko, J. J., Jr. NMR Studies I. Hydride Shifts in Alkyl Carbonium Ions. II. Nitrogen Inversion in Tertiary Amines. Ph. D. Thesis, Yale University, New Haven, Conn., 1972. 

Reduction of amides to aldehydes was accomplished mainly by complex hydrides. Not every amide is suitable for reduction to aldehyde. Good yields were obtained only with some tertiary amides and lithium aluminum hydride, lithium triethoxyaluminohydride or sodium bis 2-methoxyethoxy)aluminum hydride. The nature of the substituents on nitrogen plays a key role. Amides derived from aromatic amines such as JV-methylaniline [1103] and especially pyrrole, indole and carbazole were found most suitable for the preparation of aldehydes. By adding 0.25 mol of lithium aluminum hydride in ether to 1 mol of the amide in ethereal solution cooled to —10° to —15°, 37-60% yields of benzaldehyde were obtained from the benzoyl derivatives of the above heterocycles [1104] and 68% yield from N-methylbenzanilide [1103]. Similarly 4,4,4-trifluorobutanol was prepared in 83% yield by reduction of N-(4,4,4-trifluorobutanoyl)carbazole in ether at —10° [1105]. 

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