Dehydrogenation, of amines

Homogeneous hydrogenation of nitriles, Saturated nitriles are hydrogenated to primary amines in 67-100% yield with 1 as catalyst in THF. The catalytic activity of 1 for aromatic nitriles is not so high as for hydrogenation of aliphatic nitriles. The C=C bond of unsaturated nitriles is reduced more readily than the C=N bond. This catalyst is also eflective for dehydrogenation of amines (benzylamine — benzonitrile, 27% yield). 

Mercuric acetate, HgfOCOCHjjj (mp 179-182 °C), is used for dehydrogenations, resulting in the introduction of double bonds into the a positions with respect to conjugated systems [399, 400], and for the dehydrogenation of amines to imines [401, 402]. The reagent can also demethylate tertiary amines to secondary amines [403] and introduce acetoxyl groups into the a positions with respect to double bonds [404]. 

There are recent literature reports according to which alcohols and aldehydes dehydrogenate in the presence of ammonia to form nitriles. Process are operated by Rohm Haas, Ruhrchemie, and Bayer [21-23]. Molybdenum nitrides were found most efficient as heterogeneous catalysts [15] cf. eqs. (8) and (9) (R = n-CsHv). They also effect dehydrogenation of amines, as demonstrated for -butylamine in eq. (10). 

Dingwall, J.G., Ehrenfreund, J., and Hall, R.G., Diethoxymethylphosphonites and phosphinates. Intermediates for the synthesis of a,P- and y-aminoalkylphosphonous acids. Tetrahedron, 45, 3787, 1989. Mohrle, H., and Vetter, W., Participation of phosphonate neighbour groups with dehydrogenations of amines, Z. Naturforsch., 43b, 1662, 1988. 

Dehydrogenation of amine derivatives with Hg-EDTA can give rise to hydroxy lactams by the following sequence ... 

Scheme 16 Dehydrogenation of amine horanes catalyzed by Re(I) complexes 16-19...

Dehydrogenation of Amine Borane and Transfer Hydrogenation Using Amine Borane as a Hydrogen Source... 

One remarkable application of the Re(I) complexes of type 16-19 is the catalytic dehydrogenation of amine boranes [54], In recent years, the research on amine borane R R NH-BHs (R R = alkyl, H) became an important topic based on their capability of chemical hydrogen storage [55-57], In this respect transition metal-catalyzed dehydrocoupling reactions of amine borane offer great potential for control over both extent and rate of hydrogen release [58, 59]. 

Scheme 21 Catalytic dehydrogenation of amine boranes by a heterobimetallic Fe/Zr complex...

Scheme 28 Dehydrogenation of amine boranes catalyzed by Ti/Ru heterobimetallic complexes and proposed mechanism...

Dehydrogenation of amines may be achieved by thermolysis of sulphinamides, although benzylic or allylic activation is required to control the regioselectivity of elimination (Scheme 1)/ A biomimetic oxidative deamination of primary... 

Mohajeri, N. Tabatabaie-Raissi, A. Bokerman, G., Catalytic dehydrogenation of amine borane complexes, U.S. Patent 7578992, 2009. 

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