Nitriles primary amines from

Amides and Nitriles. Primary amines or ammonia, from the thermal decomposition of amino acids, can be acylated by carboxylic acids to produce amides (30). 

The nitrile is then hydrogenated to a primary amine from which amine derivatives can be made by utilization of a variety of reagents [6, 7]. The example in eqns 6.1.1-6.1.3 shows the conversion of fatty acid to dialkyl secondary amine via catalytic deammoniafication (for this and all subsequent structures n = 80-20 unless otherwise noted) ... 

If nascent hydrogen (e.g. from zinc and sulphuric add) be allowed to act on nitriles, primary amines are formed (Mendius reaction)... 

Primary amine formation is equally well promoted in alkaline medium, e.g., aqueous ethanolic NaOH solution, that selectively poisons the catalyst for hydrogenolysis reactions. However, saturated NH3/alcohol solutions best afford almost quantitative yields of primary amines from catalytic reduction of nitriles. Ammonia adds to imine 1 to give a 1,1-diamine, which is hydrogenolyzed to the primary amine. In the presence of NHj, finely divided Ni can be used, platinized finely divided Ni for the hydrogenation of hindered nitriles, and rhodium-on-alumina for sensitive compounds. Mild reduction of 3-indoleacetonitrile to tryptamine [equation (c)] is effected at RT over 5% rhodium-on-alumina in 10% ethanolic NH3 with little side reaction , and branched chain amino sugars are conveniently prepared using this selective hydrogenation [equation (d)] . 

The iminium ion is, of course, more electrophilic than the starting amides (amide carbonyl groups are about the least electrophilic of any ), so it gets reduced to the secondary amine. This reaction can be used to make secondary amines from primary amines and acyl chlorides. A similar reduction with lithium aluminium hydride gives a primary amine from a nitrile. 

Table 4 Synthesis of primary amines from nitriles via aluminum imines...

Further examples of the synthesis of primary amines from oximes, azides, nitriles,isocyanides,aldehydes, and Grignard reagents have also been reported. 

As far as catalytic properties are concerned, nickel and cobalt catalysts rank among those most often described and used in the production of primary amines from higher fatty acids via the hydrogenation of the corresponding nitriles. It was also assumed in previous papers that when nickel is deposited on a support, only the degre of nickel dispersion is affected and there is no substantial modification of the selectivity (5). 

Because nitriles can be prepared from alkyl halides by nucleophilic substitution with cyanide ion the overall process RX RC=N RCH2NH2 leads to primary amines that have one more carbon atom than the starting alkyl halide... 

Nitriles and oximes are considered together because of common features. Both functions are reduced to primary amines, both undergo coupling reactions to secondary amines, and both are subject to reductive hydrolysis. These similarities arise from a common intermediate, an imine. The imine is... 

A mechanistic proposal, which is based on the mthenium-catalyzed dehydration reaction reported by Nagashima and coworkers [146], is shown in Scheme 44. Reaction of a primary amine with hydrosilane in the presence of the iron catalyst affords the bis(silyl)amine a and 2 equiv. of H2. Subsequently, the isomerization of a gives the A,0-bis(silyl)imidate b and then elimination of the disiloxane from b produces the corresponding nitrile. Although the disiloxane and its monohydrolysis product were observed by and Si NMR spectroscopy and by GC-Mass-analysis, intermediates a and b were not detected. 

The selectivity of RNH2 on M/A1203 and Raney catalysts decreased in the order Co Ni Ru>Rh>Pd>Pt. This order corresponds to the opposite sequence of reducibility of metal-oxides [8] and standard reduction potentials of metalions [9], The difference between Group VIII metals in selectivity to amines can probably been explained by the difference in the electronic properties of d-bands of metals [3], It is interacting to note that the formation of secondary amine, i.e. the nucleophilic addition of primary amine on the intermediate imine can also take place on the Group VIII metal itself. Therefore, the properties of the metal d-band could affect the reactivity of the imine and its interaction with the amine. One could expect that an electron enrichment of the metal d-band will decrease the electron donation from the unsaturated -C=NH system, and the nucleophilic attack at the C atom by the amine [3], Correlation between selectivity of metals in nitrile hydrogenation and their electronic properties will be published elsewhere. 

The a-arylamino nitriles 251, obtained from primary aromatic amines, trimethylsilyl cyanide and acetone in the presence of zinc chloride, react with methyllithium to give A-t-butylarylamines 252287. Af,Af-Bis(trimethylsilyl)amines 253 (R = allyl, benzyl, 3-phenylpropyl etc.) are formed in 50-88% yields by the action of chlorotrimethylsilane on primary amines in the presence of a catalytic amount of titanium(IV) chloride288. 

Catalysed oxidation of primary and secondary amines generally has little synthetic value. Primary amines yield either a mixture of nitriles and amides (ca. 30%) or, in the case of arylamines, the azo derivatives (42-99%) [39], Symmetrical and non-symmetrical azoarenes are also produced in good yields ( 60%) from the reaction of acetanilides with nitroarenes under basic solidtliquid conditions, although higher yields are obtained using TDA-1 [40],... 

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