摘要:
Aqueous solutions of sodium salts of .alpha.-aminocarboxylic acids practically free of foreign salts are produced by saponifying the corresponding hydantoin at a temperature between 110.degree. C. and 180.degree. C. with a mixture, in each case based on the hydantoin, of 1 equivalent of sodium hydroxide and 2 equivalents of calcium oxide or hydroxide, separating off the precipitated calcium carbonate after the end of the saponification and concentrating the aqueous sodium salt solution remaining to drive off the ammonia contained therein.
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.
摘要:
There is described the resolution of the racemate (1RS,2SR)-2-amino-1-phenyl-propan-1-ol. It is carried out by means of the optical isomers of S-(carboxymethyl)-cysteine.
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:
There are produced thiazoline-(3) compounds which optionally are substituted or unsubstituted in the 2 and/or 5 positions by reaction of oxo compounds with a metal sulfides, ammonia and oxo compounds which are substituted by halogen in the position adjacent to the oxo group. In this process a mixture of oxo compounds, metal sulfides and ammonia is present and the halogen substituted oxo compound is introduced into the mixture. By using in this manner of mixing, high yields are obtained in a relatively short period of time.
摘要:
There are produced peptides by asymmetrical hydrogenation of dehydropeptides of the general formula ##STR1## in which n is a whole number from 1 to 4, R.sub.1 and R.sub.2 are the same or different, and are hydrogen, a straight or branched chain alkyl group with 1 to 10 carbon atoms, or such a group substituted with a carboxyl group, a phenyl group which is unsubstituted or substituted in the 3 or 4 position or in both the 3 and 4 positions by a hydroxyl, alkoxy, or acyloxy group or an indolyl group which is unsubstituted or substituted in the 6 position by fluorine or chlorine or an indolyl group substituted by a methyl group. R.sub.3 is hydrogen, an alkali metal, or a lower alkyl group with 1 to 4 carbon atoms, R.sub.4 is hydrogen, an acetyl group or a chloroacetyl group and R.sub.5 is hydrogen or a straight or branched chain alkyl group having 1 to 4 carbon atoms with the proviso that when n is 2, 3, or 4, the individual groups R.sub.5 are the same or different, in the presence of chiral rhodium-complexes.
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:
There is described the resolution of the racemate S-(carboxymethyl)-(RS)-cysteine. It is carried out by means of the optical isomers of 1-phenyl-ethylamine. This process makes it possible to obtain in a simple manner S-(carboxymethyl)-(R)-cysteine which is important for pharmaceutical purposes and is made from synthetically produced cysteine.
摘要:
The invention is directed to optically active 1,2-bis-(diphenylphosphino)-compounds of the general formula ##STR1## where Ph is a phenyl group and R is a straight or branched chain alkyl group with 2 to 20 carbon atoms or a benzyl group. Especially preferred are compounds in which R is an isopropyl or a benzyl group. These compounds can serve as chiral ligands in noble metal complexes, especially in rhodium complexes, which can be used as catalysts for the homogeneous asymmetrical hydrogenation of pro-chiral unsaturated compounds.
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.