摘要:
4-aminobutyramide hydrochloride is produced by saponifying 4-(benzylamino)-or-4-(dibenzylamino)-butyronitrile to the corresponding substituted 4-aminobutyramide and subjecting this in the form of the hydrochloride in the presence of an inert solvent and a platinum metal catalyst to a hydrogenation treatment whereby the benzyl group or the two benzyl groups are split off.
摘要:
The separation of L-leucine and L-isoleucine in aminoacid mixtures containing at least 30 weight percent L-leucine, at most 70 weight percent L-isoleucine and at most 40 weight percent of other aminoacids is accomplished by acetylating the mixture, precipitating the acetylation product by acidification, subjecting the aqueous solution to a saponification by an L-aminoacid acylase until 25 to 95% of the N-acetyl-L-leucine is saponified, crystallizing pure L-leucine from the saponification mixture and separating it off, isolating N-acetyl-L-isoleucine from the mother liquor and saponifying it in known manner to the free aminoacid and isolating the free aminoacid.
摘要:
3-Cyanopropionamide is produced by adding hydrocyanic acid on acrylamide in the presence of an aprotic organic solvent and an alkali metal cyanide at a temperature between 20.degree. and 150.degree. C. 3-cyanopropionamide is an important intermediate product for the production of pyrrolidone or 4-aminobutyramide.
摘要:
Pure L-leucine is obtained from an aminoacid mixture which contains at least 45 weight percent L-leucine, at most 40 weight percent L-isoleucine and at most 25 weight percent of other aminoacids by acetylating the mixture, precipitating the acetylation product by acidification, subjecting the acetylation product to a saponification by an L-aminoacid acylate until 30 to 95% of the N-acetyl-L-leucine employed is saponified and isolating the L-leucine from the saponification mixture.
摘要:
The subject matter of the invention is a process for the recovery of S-(carboxymethyl)-(R)-cysteine and S-(carboxymethyl)-(S)-cysteine from a mixture of the two enantiomers. The mixture to be separated is dissolved in water in the presence of sufficient ammonia that the ammonium salt solution formed has a pH between 6 and 9. Then there is brought about in the solution of ammonium salt a state of supersaturation by the addition of seeding crystals of the ammonium salt of one of the two enantiomers, insofar as the starting material contains one of the two enantiomers in excess, the ammonium salt of this enantiomer, the ammonium salt of one of the two enantiomers is brought to crystallization and separated off. Subsequently by addition of seeding crystals of the ammonium salt of the other enantiomers to the remaining mother liquor the ammonium salt of this enantiomer is likewise brought to crystallization and separated off. Finally the respective S-(carboxymethyl)-cysteine is set free from the two ammonium salts.
摘要:
There are prepared specific .alpha.-aminocarboxylic acids or their methyl, ethyl, or benzyl esters in which the .alpha.-amino group is substituted by a 3-cyanopropanoyl group. The compounds are useful for producing the corresponding derivatives of 4-aminobutyramide ("Gabamide") by catalytic hydrogenation of the cyano group.
摘要:
To separate the racemate (R,S)-cysteine, the racemate is condensed in an inert solvent with an enantiomerically enantiomeric monosaccharide of the group of aldoses having 4 to 7 carbon atoms to form the corresponding 2-substituted thiazolidin-4-carboxylic acid and the mixture of diastereomers obtained separated from each other. Subsequently, the isolated unitary diastereomers are reacted in an inert solvent with a carbonyl reagent to split the ring and the enantiomerically pure cysteine in each case is isolated as such or as the corresponding cystine.
摘要:
There are prepared specific .alpha.-aminocarboxylic acids or their methyl, ethyl, or benzyl esters in which the .alpha.-amino group is substituted by a 3-cyanopropanoyl group. The compounds are useful for producing the corresponding derivatives of 4-aminobutyramide ("Gabamide") by catalytic hydrogenation of the cyano group.
摘要:
4-aminobutyramide hydrochloride is produced by hydrogenation of 3-cyanopropionamide in the presence of a solvent inert under the reaction conditions, a noble metal catalyst and hydrogen chloride at a temperature between 5.degree. and 80.degree. C. The hydrochloride can be easily converted into 4-aminobutyramide which as such or in the form of derivatives has significance as a neurotransmitter.
摘要:
L-proline is produced from the methyl or ethyl ester of L-pyroglutamic acid by reacting this with at least twice the molar amount of phosgene to form the corresponding 1-chlorocarbonyl-5,5-dichloroproline ester, producing the corresponding 2-chloro-1-chlorocarbonyl-pyrrolin-(2)-carboxylic acid ester-(5) therefrom by splitting off hydrogen chloride, catalytically hydrogenating the pyrrolin-(2) compound to the corresponding N-chlorocarbonyl-proline ester and hydrolyzing the latter with acid to form L-proline.