摘要:
A method of purifying .alpha.-L-aspartyl-L-phenylalanine methyl ester as a hydrochloride salt thereof which comprises:i) contacting a mixture of .alpha.-L-aspartyl-L-phenylanaline methyl ester and .beta.-L-aspartyl-L-phenylalanine methyl ester with an aqueous medium containing (a) hydrogen chloride in an amount not more than ca. 2 mol., per liter of said aqueous medium, but not less than 1 mol., per mole of said of said mixture of .alpha.-L-aspartyl-L-phenylalanine methyl ester and .beta.-L-aspartyl-L-phenylalanine methyl ester, and (b) an inorganic chloride selected from the group consisting of NaCl, KCl, NH.sub.4 Cl, CaCl.sub.2, and ZnCl.sub.2 in an amount of at least ca. 50 g., per liter of said aqueous medium, to form crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride, andii) recovering the .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride crystals therefrom.
摘要:
A process for recovering .alpha.-L-aspartyl-L-phenylalanine methyl ester from a solution containing various methyl ester or demethylated derivatives of .alpha.-L-aspartyl-L-phenylalanine methyl ester and chloride ions is disclosed. This process uses a reverse osmosis membrane having a specific chloride inhibition rate to desalt and concentrate a solution containing a specified ratio of .delta.-L-aspartyl-L-phenylalanine methyl ester to its derivatives until a specific weight ratio of organic chloride ion to the sum of .alpha.-L-aspartyl-L-phenylalanine methyl ester and its derivatives is obtained. This desalted and concentrated solution is then contacted with an aqueous solvent containing methanol and hydrochloride acid to recover high yields of .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride.
摘要:
A method for optical resolution of a DL-amino acid comprising reacting the DL-amino acid with an optically active N-acyl aspartic acid in a solvent or mixture of solvents, and separating the resulting two diasteromeric salts by way of the difference between their solubilities in the solvent or mixture of solvents. The difference in solubility may be enhanced by cooling, concentration, addition of a solubility-decreasing organic solvent, pH adjustment or salting out.
摘要:
A readily soluble 2',3'-dideoxyinosine composition is prepared by combining 80 to 1 parts by weight of a basic amino acid and 20 to 99 parts by weight of 2',3'-dideoxyinosine. The greater solution velocity of this composition improves solubility for therapeutic uses.
摘要:
A process is described for the synthesis of N-protected-L-.alpha.-aspartyl-L-phenylalanine by both (a) the rection of an N-protected-L-aspartic anhydride and a R.sub.1 -L-phenylalanine, and (b) the reaction of an N-protected-L-aspartic anhydride and L-phenylalanine in an aqueous medium in the presence of R.sub.2, where R.sub.1 may be an alkali metal salt, alkaline earth metal salt, ammonium salt or organic amine salt, and R.sub.2 may be an ammonium salt or an alkali or alkaline earth metal salt of an inorganic or organic acid.
摘要:
A ruminant feed additive composition comprises a phosphoric acid-amino acid composite salt and a water-insoluble salt of a polyvalent-metal-sensitive water-soluble high-molecular weight substance. The composite salt contains a basic amino acid, an alkaline-earth metal and phosphoric acid, and is insoluble in neutral or alkaline aqueous solution, but is soluble in acidic aqueous solution.
摘要:
A ruminant feed additive composition in the form of a powder or granules comprises as active ingredients a gastric antacid, a phosphoric acid-amino acid-polyvalent metal composite salt and optionally a water-insoluble salt of a polyvalent metal-sensitive water-soluble high-molecular weight substance. The phosphoric acid-amino acid-polyvalent metal composite salt is composed of a phosphoric acid such as orthophosphoric acid, a polyphosphoric acid or a metaphosphoric acid, a basic amino acid such as lysine or methionine, an alkaline earth metal such as calcium or magnesium and, optionally, a polyvalent metal such as aluminum.
摘要:
Tripeptide sweeteners represented by formula (I)X--Asp--Y--ORwhereinX is glycine or a D or DL-isomer of alanine, .alpha.-aminobutyric acid, serine, threonine, norvaline, asparagine, B-methyl aspartate, proline or pipecolic acid, andY is a D, L or DL-isomer of alanine, phenylalanine, phenylglycine, serine or .beta.-aminobutyric acid or a salt thereof, andR is methyl, ethyl, propyl or isopropyl, are disclosed.
摘要:
The present specification discloses a ruminant feed additive composition which contains as an active ingredient a phosphoric acid-amino acid-polyvalent metal composite salt (final composite salt) which is insoluble in neutral or alkaline water and is soluble in acidic water and which can be obtained by treating a composite salt composed of a basic amino acid, magnesium and phosphoric acid with a salt of a divalent or trivalent (polyvalent) metal other than magnesium, or by treating the above-mentioned composite salt with the polyvalent metal salt and a condensed phosphoric acid component (alone) or the condensed phosphoric acid component and a phosphoric acid component (in combination), this composition taking the form of a powder or granules. The above-mentioned final composite salt can exhibit the excellent stability to neutral or slightly acidic water, namely, the low solubility therein in comparison with the intermediate composite salt, and it can have both the excellent insolubility of the basic amino acid in a rumen of a ruminant and the excellent elution thereof in an abomasum and lower digestive organs.
摘要:
N-formyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester is obtained by reacting L-phenylalanine methyl ester with N-formyl-L-aspartic acid anhydride in a reaction solvent containing acetic acid or acetic acid and formic acid in a complete mixing type continuous reaction mode.