Akabori amino acid reaction

Akabori amino acid reactions. (1) Formation of aldehydes by oxidative decomposition of a-amino acids when heated with sugars. (2) Reduction of a-amino acids and esters by sodium amalgam and ethanolic hydrochloric acid to the corresponding a-amino aldehydes. (3) Formation of alkamines by... 

Other references related to the Akabori amino acid reaction are cited in literature. ... 

Akabori Amino Acid Reactions Alder (see Diels-Alder Reaction)... 

Anuno acids are converted into aldehydes, the most popular method being the Strecker degradatioa The amino acid is simply mixed with reagoits such as niitiiydrin and heated to form ammonia and carbon dioxide as by-products. Sodium hypochlorite can be used in a process accelerated by UV irradiation. A similar reaction is the Akabori reaction where the amino acid is heated with compounds such as glucose to give alddiydes, as in the Strecko process. ... 

One of initial studies was microwave-assisted Akabori reaction for peptide analysis [100]. The classical Akabori reaction [101], devised in 1952 for the identihcation of C-terminus amino acids, involved the heating of a hnear peptide in the presence of anhydrous hydrazine in a sealed tube for several hours. The C-terminus group is liberated as free amino acid and can be distinguished from the remaining amino acid residues that have been converted to hydrazides. The reaction mechanism is illustrated in Figure 19-16. 

Their proposed fragment ion structures were supported by accurate mass measurements, as shown in Figure 19-18. Clearly, microwave-assisted Akabori reaction can lead to rapid identification of C-terminus amino acid in a polypeptide including its amino acid sequence information at both C-terminus and the N-terminus. It was also found that microwave-assisted hydrazinolysis of N-terminal substituted polypeptides followed the same... 

Originally devised as a method for the conversion of amino acids or amino acid esters to aldehydes. The Akabori reaction has been modihed for use in the determination of C-terminal amino acids by performing the reaction in the presence of hydrazine and for the production of derivatives useful for mass spectrometric identihcation. See Ambach, E. and Beck, W., Metal-complexes with biologically important ligands. 35. Nickel, cobalt, palladium, and platinum complexes with Schiff-bases of... 

The reaction between a suitable imidatc and an a-aminoaldehyde or a-aminoacetal to form an amidine, which cyclizes to an imidazole, rests largely on the availability of the aminoaldehydes from a-amino acids, which are readily reduced using the Akabori method [2], Dimethyl or diethyl acetals frequently replace the aldehydes in these reactions 13,4]. Table 2.2.1 lists some 2,5-disub.stituted imidazoles prepared (ultimately) from amino acids. It is not possible to introduce a range of substituents at both the 4- and 5-positions by this method unless the amino acid is converted into a ketone rather than an aldehyde (see Section 2.1.1) (Scheme 2.2.2). 

According to Akabori and Momotani (269), a mixture of an aromatic aldehyde and an amino acid on heating yield alkamines. By means of this reaction, ephedrine and norephedrine were synthesized. 

The higher optical 5delds were achieved with the addition of L-amino acids to die reaction mixtures. The addition of L-tyrosine resulted in the formation of phenylalanine with an ee of 50%. Unfortunately, these data were not noticed for some time and only in 1963 did the group of Akabori and Izumi attempt to reproduee these results however, the first results were of modest success even using other methods of preparation of the catalysts. 

This reaction was first reported by Akabori in 1931. It is the synthesis of an aldehyde, an a-amino aldehyde, or a primary amine from a-amino acid under different reaction conditions. In the presence of a reducing agent (usually a reducing sugar), an a-amino acid is oxidized to an aldehyde and ammonia by molecular oxygen (Scheme 1). For comparison, the a-amino acid ester is reduced by sodium amalgam in alcoholic solution in the presence of hydrochloric acid to give an a-amino aldehyde (Scheme 2). However, under pyrolytic condition, the a-amino acid is converted to primary amine in the presence of benzaldehyde (Scheme 3). 

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