- METHOD OF SEPARATING AND COLLECTING OPTICALLY ACTIVE AMINO ACID AMIDE
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[PROBLEMS] To provide a method of efficiently separating and collecting an optically active amino acid amide and an optically active amino acid, which are highly important substances as intermediates in producing various industrial products, pesticides and medicines, from an aqueous solution containing the optically active amino acid amide and the optically active amino acid. [MEANS FOR SOLVING PROBLEMS] In separating and collecting an optically active amino acid amide from an aqueous solution containing the optically active amino acid amide and an optically active amino acid by using the difference in solubility in an organic solvent between the optically active amino acid amide and the optically active amino acid, the separation/collection procedures are carried out, without desalting the aqueous solution or after desalting the same, under such conditions that the ratio (C/A) of the sum of the anionic equivalents (A) contained in the aqueous solution to the sum of the cation equivalents (C) ranges from 0.95 to 1.05 in the case of the non-desalted aqueous solution, or from 0.5 to 1.5 in the case of the desalted aqueous solution.
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Page/Page column 11-12;13
(2008/06/13)
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- Racemic Structures of Organic Ammonium Salts of N-Acetyl-DL-2-aminobutyric Acid and N-Acetyl-DL-norvaline and Optical Resolution by Preferential Crystallization of DL-Ammonium Salts
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The racemic structures of the ammonium salts (AM salts) and seven organic ammonium salts of N-acetyl-DL-2-aminobutyric acid (Dl-AcAbu) and N-acetyl-DL-norvaline (DL-AcNva) were studied on the basis of thermodynamic analyses to explore the possibility of optical resolution by preferential crystallization.An empirical equation has been derived from thermodynamic data and melting points of ammonium and organic ammonium salts of N-acyl-DL-amino acids to predict racemic structure around room temperature.The AM salts of DL-AcAbu and -AcNva exist in conglomerate around room temperature.It is possible to resolve optically these DL-AM salts by preferential crystallization in ethanol at 10 deg C, and the succesive preferential crystallization followed by purification gave D- and L-2-aminobutyric acids and -norvalines with optical purities close to 100percent.
- Shiraiwa, Tadashi,Yoshida, Hirokazu,Tsuda, Makoto,Kurokawa, Hidemoto
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p. 947 - 952
(2007/10/02)
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