Akabori method

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). 

The most convenient method of making a-aminoaldehydes is by reduction of a-amino acid esters using sodium amalgam [5, 6] by what has come to be known as the Akabori method. Alternatively, an a-halogenocarbonyl compound can be converted via the Gabriel synthesis into the aminocarbonyl... 

Peptide analysis. In the Akabori method for determination of the C-terminal amino acid, the peptide is heated with anhydrous hydrazine at 100-120° for about 8 hrs. to convert internal units into amino acid hydrazides and liberate the free acid from the terminal unit. Unfortunately several amino acids are decomposed under... 

Akabori method, an approach to C-terminal amino acid end group analysis of peptides using hydrazine. By treatment of the peptide under investigation with anhydrous hydrazine for 90-100 h at 90°C in the presence of an acidic ion-exchange resin, only the C-terminal amino acid residue... 

Akabori, Shiro (1900-1992), professor of organic chemistry at Osaka University (1939-1966), known as the father of peptide chemistry in Japan, with outstanding international achievements in peptide research, inter alia Akabori method. From 1960 onwards, and even after his retirement in 1966, Professor Akabori continuously served the scientific community for over 20 years as president of the Protein Research Foundation Japan. 

End group analysis, determination of N-terminal (— dinitrophenyl method, —> dansyl method, Edman degradation) and C-terminal C-terminal end group analysis, Akabori method) amino acid residues in the primary structure analysis of peptides and proteins. 

Akabori, K. Fujimoto, H. A Method for Measuring Cell Membrane Thickness of Polyurethane Foam, International Progress in -Urethanes. 1980, 2, 1-61. 

Von einer Reihe chomischcr Methoden, welche die Bestimmung oder den schrittweisen Abbau von Aminosauren vom C-tcrminalen Kcttenende her zumZiclc hatten (siehe z.B. bei Bailey (8), ist bislier nur die Hy-drazin-Methode von Akabori praktisch bedeutungsvoll geworden. 

Die Methode von Akabori. Werden Peptide odor Protcinc mit was-serfreiem Hydrazin crliitzt, so werden die Peptidbindungen gesprengt und es bilden sich Aminosaure-Hydrazide. Nur die C-terminate Amino-saure -wird als solche abgespalten. 

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. ... 

S. Akabori, K. Ohno, and K. Narita, On the hydrazinolysis of proteins and peptides A method for the characterization of carboxy-terminal amino acids in proteins, Bull. Chem. Soc. Japan 25 (1952), 214-218. 

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 third COOH-terminal method applied to gelatin has been the hydrazinolysis method, carried out by Heyns and Legler (1957, 1958). This method (Akabori et al., 1956) involves treatment of the protein with... 

Wl. Waldschmidt-Leitz, E., and Akabori, S., Bestimmung von ox5T>rolin. Zur method nach K. Lang. Z. Physiol. Chem. 224, 187-192 (1934). 

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. 

Also in Osaka, another former student of Akabori, professor Tetsuo Shiba (Plate 43) and his associates developed a procedure for the preparation of lanthionine-containing peptides and applied it, in 1988, to the synthesis of the antibiotic nisin (p. 223). In Tokyo, at Rikkyo University, professor Ichiro Muramatsu, also from the Akabori school, proposed a rapid method of synthesis and discovered novel side reactions, such as the formation of guanidine derivatives during coupling with carbodiimides. 

Numerous methods were proposed for this purpose, but only few withstood the test of time. A reliable procedure is hydrazinolysis (Akabori et al. 1952) which involves the heating of a solution of the peptide in ca. 97 % hydrazine in a sealed tube at 100 °C for 12 hours. The peptide bonds are cleaved by hydrazine and the amino acid constituents thus converted to amino acid hydrazides except the C-terminal residue which is merely hberated in the process. Its separation is faciUtated by dinitrophenylation of the mixture with 2,4-dinitrofluorobenzene. The DNP-amino acid hydrazides as neutral substances are extracted from the aqueous, bicarbonate containing mixture with an organic solvent while the sodium salt of the DNP-derivative of the C-terminal amino acid remains dissolved ... 

Soda, T. in S. Akabori, ed., Textbook of Enzymological Methods II. 73 (1956). Tokyo Asakura Press. 

Goto, M., K. Akabori, and S. Maeda. 1994. Development of a flow injection method based on bromometry and iodometry for pharmaceutical analysis. Bunseki Kagaku 43 505-509. 

Akabori, S., Ohno, K., Ikenaka, T., Nagata, A., Haruna, I. Improved methods for the characterization and quantitative estimation of carboxyl-terminal amino acids in proteins. Proc. Jap. Acad. 29, 561—564 (1953). 

The method of asymmetric synthesis based on active catalysts is of great importance at present. The Japanese researcher Akabori [46], who obtained amino acids by hydrogenating suitable substrates in the presence of a palladium catalyst, first carried out such a synthesis. In turn, Izumi noticed that far better results could be... 

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