The Synthesis of Amines

Although this reaction is useful for preparing a ammo acids (Table 22 3 fifth entry) it IS not a general method for the synthesis of amines Its major limitation is that the expected primary amine product is itself a nucleophile and competes with ammonia for the alkyl halide... 

In this representation the FeCl2 which takes part in the first step of the reaction is not a tme catalyst, but is continuously formed from HQ. and iron. This is a highly exothermic process with a heat of reaction of 546 kj /mol (130 kcal/mol) for the combined charging and reaction steps (50). Despite the complexity of the Bnchamp process, yields of 90—98% are often obtained. One of the major advantages of the Bnchamp process over catalytic hydrogenation is that it can be mn at atmospheric pressure. This eliminates the need for expensive high pressure equipment and makes it practical for use in small batch operations. The Bnchamp process can also be used in the laboratory for the synthesis of amines when catalytic hydrogenation caimot be used (51). 

Using a procedure similar to the synthesis of amine boranes, a series of amine cyanoboranes where the amine = (CH3)3N, (CH3)2NH, (CH3)NH2, C3H3N, or (CgH3)NH2 have been prepared as shown in equation 4 (11). 

Reduction of amides by LiAlH4 is an important method for the synthesis of amines. 

A valuable application of sodium cyanoborohydride is in the synthesis of amines by reductive amination. What combination of carbonyl and amine components would give the following amines by this method ... 

The synthesis of amines by the in-situ reductive amination of ketones is termed the Leuckart-Wallach reaction. Recently, an asymmetric transfer hydrogenation version of this reaction has been realized [85]. Whilst many catalysts tested give significant amounts of the alcohol, a few produced almost quantitative levels of the chiral amine, in high enantiomeric excess. 

Nucleophilic displacement, for the synthesis of Amines, thiols, halides, azides, acetates [204, 205]... 

The development of versatile and efficient methods for the synthesis of amines has long been an active area of research, mainly because a wide variety of amines play important roles in many fields of organic chemistry. The N-alkylation of amines with alcohols represents an attractive method for synthesizing various amines because it does not generate any wasteful byproducts (H2O is the only stoichiometric coproduct). Although several catalytic systems for this process have been studied using transition-metal catalysts [53-57], most of these require a high reaction temperature (>150°C). 

The synthesis of amines from oximes is exemplified by the reduction of oxime 332 to 333 (99W032453) and of bicyclic oximes (derived from ketones 3 and 23a), for instance, of oxime 387 (Scheme 87) to amine 388 that is acylated to yield potential pharmaceutical agent 390 (92BML1147). Nucleophilic substitution of chloropyridine 384 generates morpholino derivative 385 (76IJB400). 

This methodology is also an important and potentially valuable method for C—N bond formation using the amination of carbon nucleophiles with electrophilic nitrogen transfer reagents (Scheme 1) Amination of ordinary carbanions and a-carbanion derived from carbonyl compounds and nitriles provides an important method for the synthesis of amines and a-amino carbonyl compounds and nitriles", respectively. For this purpose, a number of electrophilic amination reagents, which are synthetic equivalents of the R2N+ synthon, have been developed and the synthetic potential of electrophilic amination of carbon nucleophiles has been studied in detail . ... 

A. Lattes, Afinidad 1972, 2953 -2970 . .Application of Organometallic Compounds to the Synthesis of Amines and Nitrogenated Heterocycles". 

The electrophilic amination reaction of organometallic species using mono-, di- and trihaloamines has attracted a lot of attention for the synthesis of amines. Only a few cases have been reported using alkylchloroamines as precursors for the synthesis of tertiary amines One example is the reaction of functionalized aryhnagnesium compounds with benzyl-V-chloroamines 252 providing polyfunctional tertiary amines 253 (equation 164) °. The procedure was also applied for the preparation of chiral V-chloro-amines with retention of chirahty at the a-carbon. However, the amination process is limited to benzyl-V-chloroamines. 

A one-pot method for the synthesis of amine-stabilized gold nanoparticles using... 

Figure 10.1. Strategies for the synthesis of amines on insoluble supports. X leaving group R alkyl, aryl.

Almost any nitrogen-containing organic compound can be reduced to an amine. The synthesis of amines then becomes a question of the availability of suitable precursors and the choice of an appropriate reducing agent. 

These and related reactions are discussed in further detail in the following sections. For your convenience, a tabular summary of methods for the synthesis of amines appears in Tables 23-6 and 23-7. 

The hydrogenation activity of W2C/Zeolite Y was evaluated in the synthesis of amines. The standard conditions reported earlier were followed. Although traditionally a Ni catalyst is used for hydrogenation, there is a need for a hydrogenation catalyst that is more sulfur resistant than Ni. It was found that the W2C/Zeolite Y may act as a hydrogenation catalyst for acetonitrile. Acetonitrile conversion was found to be high at 573-723 K, but the selectivity was low. A mixture of ethylamine, diethylamine and hydrocarbons was formed, Table 22.2. In this reaction, about 15% of the products could not be accounted for and further work is needed to investigate this reaction. 

Dialonzo and Siggia reported a method for determining several compounds including salicylamide based on the use of Hofmann reaction for the synthesis of amines... 

This particular feature of P-N bond containing compounds can be utilized for synthetic purposes by using "phosphoryl protection" in the synthesis of amines based on alkylative procedures. The solution of this problem introducing two new reagents, i.e. diphenyl-phosphinic amide (I) and sodium N-(t-butyloxycarbonyl) diethyl phosphoroamidate (II) as useful synthetic equivalents of an amino moiety is the subject of this communication. 

Several publications report on the synthesis of amine- and ethylenediamine-bridged PMOs, in which a second bis-silylated precursor acts as the main network builder291-293... 

The procedure described for the preparation of ethylenediamine-bisborane is general for the synthesis of amine-boranes and of borane adducts of other electron donors in which elements such as phosphorus and sulfur serve as the donor atom. In addition to the procedure used here for triphenylphosphine-borane, borane adducts of phosphines have been prepared by Analytical reagent grade (Mallinckrodt). 

The synthesis of amines poses a special problem because only in certain cases is the obvious disconnection successful. 

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