Amines by reductive alkylation

For a review of the preparation of tertiary amines by reductive alkylation, see Spialter, L. ... 

The preparation of tertiary amines by reductive alkylation of ammonia appears to find only limited application. Triethylamine and tripropylamine were prepared by hydrogenation of acetaldehyde and propionaldehyde, respectively, in the presence of ammonia over platinum catalyst.38 A high yield (84.1% by GC) of trinonylamine was... 

Malz, Jr. and Greenfield studied the preparation of tertiary amines by reductive alkylation of aliphatic secondary amines with ketones, using platinum metals and their sulfides as catalysts.40 Excellent yields of tertiary amines were obtained with unhindered ketones, such as cyclohexanone and acetone, and relatively unhindered secondary amines. In this study, 5% Pd-C and various transition metal sulfides were compared in the reductive alkylation of dibutylamine with cyclohexanone. By using the reaction conditions suitable to each catalyst, excellent yields of tertiary amines were obtained, as shown in Table 6.5. Approximately 5-15% of the excess cyclohex-... 

Alkyl groups may be introduced into ammonia, a primary amine, or a secondary amine by means of an aldehyde or ketone in the presence of a reducing agent, such as molecular hydrogen and a catalyst, active metals and acids, or formic acid or one of its derivatives. When the reducing agent is formic acid or a derivative, the reaction is known as the Leuckart reaction and is discussed elsewhere (method 432). An excellent review of the preparation of amines by reductive alkylation has been presented. This article includes a discussion of the scope and utility of the reaction, a selection of experimental conditions, illustrative preparations, and a tabulation of primary, secondary, and tertiary amines prepared thereby. ... 

The Preparation of Amines by Reductive Alkylation William S. Emerson... 

Preparation of secondary amines by reductive alkylation of ammonia is not such a general reaction as that of primary amines. In the aliphatic series treating ammonia with 2 moles of a carbonyl compound usually affords a mixture of mono-, di-, and tri-alkylamines. However, 80-90% yields of the corresponding dibenzylamine are obtained from benzaldehyde or its o-chloro or o-methyl derivative.996... 

Attempts to prepare tertiary amines by reductive alkylation have in general proved unsatisfactory the only significant reactions are the methylation of secondary and the dimethylation of primary amines by formaldehyde. Bowman and Stroud1008 described the preparation of a series of aliphatic dimethyl-amino acids by hydrogenation of mixtures of amino acids and formaldehyde in the presence of palladium-charcoal at atmospheric pressure. In most cases results are improved if the aldehyde is added gradually to the reaction mixture. In the methylation of aromatic amines special precautions are necessary to prevent condensation of the formaldehyde with the aromatic ring.1009... 

---