Tertiary amines through reductive amination

Catalytic hydrogenation of the nitrile function of cyanohydrins can give amines. As in the case of ordinary nitriles, catalytic reduction of cyanohydrins can yield a mixture of primary, secondary, and tertiary amines. Addition of acid or acetic anhydride to the reaction medium minimizes formation of secondary or tertiary amines through formation of the amine salt or acetamide derivative of the primary amine. 

The oxidative cleavage/reductive amination sequence was readily scaled. After standard aqueous workup, the final manipulation involved a simple filtration through silica gel to remove salts, polar by-products, and residual osmium from 5. The success of this procedure stems from the remarkable nonpolar nature of the tertiary amine. In the favored chair conformation, the 3,5-bicyclic aryl group shields the axial nitrogen lone pair and ensures an equatorial disposition of the benzyl group (Figure... 

C Preparation of Primary, Secondary, and Tertiary Amines through Reductive Amination... 

Aldehydes and ketones can be converted to amines through catalytic or chemical reduction in the presence of ammonia or an amine. Primary, secondary, and tertiary amines can be prepared this way ... 

AD Preparation of Primary, Seconda, or Tertiary Amines through Reduction of Nitriles, Oximes, ancT Amides... 

Direct conversion of fatty alcohols to primary amines by reaction with ammonia is not commercially practised but new catalyst developments show improved yields with this technology [10]. However, production of dialkylamines from alcohols is practised particularly with C8-C10 alcohols due to the limited availability of the corresponding acids. Alcohols are commonly used in the manufacture of tertiary alkyldimethylamines either through reductive amination with dimethylamine or by conversion to the alkylhaUde followed by reaction with dimethylamine. Both primary and secondary amines can be reacted with alcohols to produce tertiary trialkyl amines [11]. The chain branching seen with some synthetic alcohols means that the derived amines are not identical to those from natural sources. 

Thus, two major differences between the reductive alkylation of primary and secondary amines are the increased steric hindrance in the latter case, and the fact that tertiary amine formation cannot proceed through a ketimine intermediate. 

Fig. 7. A three-input INHIBIT gate exemplified by the tetraanion 54 and /1-cyclodextrin (j8-CD). a With neither protons nor /1-CD present in the solution, phosphorescent output is low, because of both PET from the tertiary amine, and through intermolecular triplet-triplet collisions of the bromonaphthalene phosphor, b Addition of calcium ions leads to a reduction in the PET-based quenching of the phosphorescence - however, intermolecular collisions still lead to a low emission, c Shielding of the phosphor with /l-CD reduces intermolecular triplet annihilations, but quenching still occurs via PET. d Only with both Ca2+ and /1-CD present does the solution phosphoresce, e In any combination of Ca2+ and /1-CD, the solution will yield a low output in the presence of molecular oxygen (the INHIBIT stimulus), as a consequence of triplet-triplet collisions...

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