Amino reaction with carbonyl compound

Reaction With Carbonyl Compounds. Primary and secondary nitroparaffins undergo aldol-type reactions with a variety of aldehydes and ketones to give nitro alcohols (11). Those derived from the lower nitroparaffins and formaldehyde are available commercially (see Nitro alcohols). Nitro alcohols can be reduced to the corresponding amino alcohols (see Alkanolamines). 

In addition to the reaction of amino groups with carbonyl compounds, in another useful method for the preparation of imines the reduction or condensation of nitriles with other reagents is employed (Eq. 2). Other more specialized methods [lb] are described in Section 5. 

Some reviews (41, 52-54) are available. The positive aspects are found in the production of desirable flavors and aromas. Fujimaki and Kurata ( 55) listed aldehydes and pyrazines, volatile compounds produced by heating amino acids with carbonyl compounds, isovaleraldehyde produced by reaction of leucine with carbonyl compounds (aldehydes,... 

N-Amino groups can be alkylated and acylated by way of their anions, and they take part in the usual reactions with carbonyl compounds, with carbodiimides, and in aza-Wittig reactions. 1-Aminobenzimidazoles and their quaternary salts react similarly, and the Schiff bases formed can lead to cyclized products. 

Unusual carbanions. Lithium homoenolates are formed from P-aryl-a,P-unsaturated ketones and esters. Their reaction with carbonyl compounds leads to y-lactols and lactones. Reductive dechlorination of a-chloroimines provides a-amino carbanions. Access to 1,2-amino alcohols is assured. 

Two particular reactions are characteristic of the (3-functional alkyltin compounds. First, conjugative electron attraction by the functional group makes C-C=X a good leaving group, and the Sn-C bond has an enhanced reactivity in substitution (e.g. hydrolysis) and addition where C=X is a nitrile, ketone, ester, or amino group, the compounds add across the N=C bond in isocyanates, and undergo Reformatsky-type reactions with carbonyl compounds.91-92... 

The degradation of carboxylic acid has been used for the preparation of amines, amino acids, and structural elucidation, especially via labeling. The reaction with carbonyl compounds has an even wider application in organic synthesis. 

Figure 2.54 Reaction of amino acids with carbonyl compounds.

The alkylation of amino- and nitramino-pyridines and anions from them has been discussed (pp. 181-2). The case of reductive alkylation is mentioned below under reactions with carbonyl compounds. 

Griffith, R. and Hammond, E.G. (1989) Generation of Swiss cheese flavor components by the reaction of amino acids with carbonyl compounds. J Dairy Sci 72, 604-613. 

The azlactones of a-benzoylaminocinnamic acids have traditionally been prepared by the action of hippuric acid (1, Ri = Ph) and acetic anhydride upon aromatic aldehydes, usually in the presence of sodium acetate. The formation of the oxazolone (2) in Erlenmeyer-Plochl synthesis is supported by good evidence. The method is a way to important intermediate products used in the synthesis of a-amino acids, peptides and related compounds. The aldol condensation reaction of azlactones (2) with carbonyl compounds is often followed by hydrolysis to provide unsaturated a-acylamino acid (4). Reduction yields the corresponding amino acid (6), while drastic hydrolysis gives the a-0X0 acid (5). ... 

The direct reductive amination (DRA) is a useful method for the synthesis of amino derivatives from carbonyl compounds, amines, and H2. Precious-metal (Ru [130-132], Rh [133-137], Ir [138-142], Pd [143]) catalyzed reactions are well known to date. The first Fe-catalyzed DRA reaction was reported by Bhanage and coworkers in 2008 (Scheme 42) [144]. Although the reaction conditions are not mild (high temperature, moderate H2 pressure), the hydrogenation of imines and/or enam-ines, which are generated by reaction of organic carbonyl compounds with amines, produces various substituted aryl and/or alkyl amines. A dihydrogen or dihydride iron complex was proposed as a reactive intermediate within the catalytic cycle. 

A wide variety of compounds having the primary amino group condense with carbonyl compounds to give )C=N— compounds by the elimination of water. The latter reactions are usually acid catalyzed because protonation of the carbonyl group enhances its reactivity toward nucleophilic attack by the amino group on the carbonyl carbon atom (Eq. 1). 

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