摘要:
A method for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester having improved solubilization by the isolation thereof from an aqueous medium containing at least one additive selected from the group consisting of sodium alginate, sodium salt of carboxymethylcellulose, sodium starch glycolate and sodium polyacrylate.
摘要:
This invention relates to an improved process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester. More specifically, it relates to a process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester which comprises treating, as a raw material, N-formyl-.alpha.-L-aspartyl-L-phenylalanine in methanol in the presence of an acid to form .alpha.-L-aspartyl-L-phenylalanine dimethyl ester, hydrolyzing the .alpha.-L-aspartyl-L-phenylalanine dimethyl ester by bringing it into contact with hydrochloric acid in the presence of methanol as desired, separating the thereby-precipitated .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride and neutralizing the hydrochloride. Further, this invention also provides a process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester capable of using, as a raw material, N-formyl-.alpha.-L-aspartyl-L-phenylalanine which contains N-formyl-.beta.-L-aspartyl-L-phenylalanine in an amount of 30% by weight or less.
摘要:
This invention relates to an improved process for preparing N-formyl-.alpha.- aspartyl phenylalanine. More specifically, it relates to a process for preparing N-formyl-.alpha.-aspartyl phenylalanine by condensating N-formyl aspartic acid anhydride and phenylalanine which comprises effecting the condensation reaction in a water medium while maintaining the pH during the reaction in the range of 7-12 and at a reaction temperature of 50.degree. C. or below.
摘要:
In the production of a .beta.-phenylserine by reacting glycine with a benzaldehyde in the presence of an alkali and treating the product with an acid, a novel process which comprises carrying out the reaction in a mixed solvent composed of water and a hydrophobic organic solvent. The presence of a phase transfer catalyst or a surface-active agent in this reaction system promotes the reaction and the .beta.-phenylserine can be obtained in a high yield.
摘要:
A process for producing a 2,3-dihalopropionitrile is provided which comprises directly halogenating acrylonitrile with a halogenating agent in the presence of a carbonate, hydrogen carbonate or hydrogen phosphate of an alkali or alkaline earth metal and in the absence of positive irradiation of light.
摘要:
A process for producing an alpha-halogeno-beta-aminopropionitrile which comprises reacting an alpha,beta-dihalogenopropionitrile with ammonia in water and/or an organic solvent. Action of a mineral acid on the reaction product gives a mineral acid salt of an alpha-halogeno-beta-aminopropionitrile. An isolated alpha-halogeno-beta-aminopropionitrile and a sulfate thereof are also provided.
摘要:
An oxidation-reducing reagent for a wet desulfurization process, which comprises (a) one or more compounds selected from the group consisting of salts of substituted anthraquinonesulfonic acids of the general formulas: ##STR1## wherein M stands for a sodium atom, a potassium atom or an ammonium group, and n is an integer of 1 or 2, or (b) a mixture of a salt of anthraquinone-2,7-disulfonic acid and one or more compounds shown by the general formula (I) and/or (II), as well as a process for preparing the compounds of the general formulas (I) and (II).
摘要:
An oxidation-reducing reagent for a wet desulfurization process, which comprises (a) one or more compounds selected from the group consisting of salts of substituted anthraquinonesulfonic acids of the general formulas: ##STR1## wherein M stands for a sodium atom, a potassium atom or an ammonium group, and n is an integer of 1 or 2, or (b) a mixture of a salt of anthraquinone-2,7-disulfonic acid and one or more compounds shown by the general formula (I) and/or (II), as well as a process for preparing the compounds of the general formulas (I) and (II).
摘要:
An improved process for producing allyl bromides by halogen exchange by reaction of an allyl chloride, with a metal bromide, wherein the reaction is conducted in an aprotic polar solvent. The allyl bromides obtained by the process of the invention are useful as intermediates for producing medicines, agricultural chemicals, dyes, and the like.