Amines transalkylation

Aliphatic amine transalkylation has been observed on alumina by Derrien and Jungers (10) and by Gatry and Jungers (11) at a higher temperature. Under the experimental conditions used here, an acid-catalyzed mechanism seems to be acceptable. An explanation that would lead to... 

Kaesz et al. have shown that simple, primary amines (e.g. MeNH2) will react with Ru3(CO)12 to form p-acetamido ligands at temperatures as low as -15°C. We find that simple primary, secondary and tertiary alkyl amines will react with Ru3(CO) 2 at temperatures of 70-150°C to undergo catalytic deuterium for hydrogen exchange reactions on the hydrocarbon groups and transalkylation (52). We have found that a... 

At temperatures above 250°C, the olefin-forming reactions are irreversible but the transformations in the first line of Scheme 3 are reversible. Thus, starting with an arbitrary amine, all other derivatives are obtained by these reactions, called disproportionations, transalkylations or dismutations (the nomenclature is also inconsistent in that the analoguous formation of ethers from alcohols is named dehydration). 

Dealkylation or transalkylation of t-amines. N-Oxides of r-amines on treatment with this triflate form silyloxyammonium salts (2), which rearrange in the presence of methyllithium to a-silyloxyamines (3). These can be converted into, r -amines (4). 

The HDN of aliphatic amines (equation 25) is relevant to the HDN of indoles (equation 26), pyridine (equation 27), and quinoline (equation 28) because these heterocycles are first hydrogenated to the aliphatic amines. A general mechanism proposed for the HDN of aliphatic amines is based on metal cluster catalysis of the transalkylation reaction in equation (33) and on metal complex catalyzed exchange of deuterimn for hydrogen in tertiary aliphatic amines (equation 34). There are other examples of amine activation in metal complexes. 

Catalytic transalkylation reactions of tertiary amines have been described with Os3(CO)12 (398-400), Ru3(CO),2 (398-401), Ir4(CO)12 (398), and Os3(CO)10S (402). In the catalytic alkyl exchange between triethylamine and tripropylamine... 

The equilibrium point lies far to the left and little methyl acetate (CH3COOCH3) is formed if water in not removed. By reactive distillation it is possible to continuously remove water and considerably intensify the reaction. Eastman Chemical pioneered one of the first major applications of reactive distillation, to significantly simplify the production of methyl acetate (Figure 3.7). This unit first went into operation in 1983. Among typical reactions where a by-product prevents the reaction from going to the right are esterification, trans-esterification, hydrolysis, acetalization and amination. Other types of reactions that could benefit from reactive distillation include alkylation/transalkylation/dealkylation, isomerization and chlorination. 

Transalkylation of amines with alcohols is usually an undesired side-reaction which reduces amination selectivity. Several metals, e. g. Co, Fe, Ni, or Ru, are good catalysts of interchange between alcohols and amines, including tertiary amines [3]. This reaction can be used for the synthesis of asymmetric tertiary amines. Triethylamine, for example, can be transalkylated with dodecanol over a Ni-Cr alloy catalyst, at 250 °C and 15 bar, to form dodecyldimethylamine in 96 % yield. 

Butyldimethylsilyloxy)-Af-methylpiperidinium triflate is quantitatively formed from the reaction of Af-methylpiperidine Af-oxide (eq 13). The resulting amine salts derived from various tri-alkylamine iV-oxides undergo transalkylation by treatment with methyllithium in THF at 0 °C followed by alkyl halides and tetra-n-butylammonium Fluoride in a sealed tube at 110 °C for 10 h, to afford trisubstituted amines (eq 14). ... 

---