摘要:
The invention relates to a method of preparing 5-(aminoalkyl)-hydantoins with basic side chain in which the protection of the amino function in the side chain is necessary during the formation of the hydantoin requires minimal expense.
摘要:
The present invention relates to a process for the resolution of DL-racemic mixtures of compounds which crystalize in the form of a conglumerate. Both, the D and L-enantiomers are obtained according to the invention in a industrially feasable process by adding chiral enantioselective polymers to the supersaturated solution of the racemat to inhibit crystalization of one enantiomer. Next a DL-racemic mixture of said compound is suspended in about twice the amount of the crystallized enantiomer. Consequently, the opposite enantiomer could be recovered by said suspension by physical separation.
摘要:
The invention concerns a process for the enzymatic preparation of protected di- and oligopeptides and the separation of the protective groups used. The process according to the invention enables peptides to be synthesized simply and economically and the protective group to be separated carefully. The process comprises three reaction steps: 1. Preparation of N-carbamoyl amino acid or N-carbamoyl amino acid derivatives; 2. Formation of the peptide bond between the carbamoyl-protected electrophile and nucelophile; and 3. Separation of the carbamoyl-protective group.
摘要:
The invention pertains to a process for the continuous production of basic cyclic optically active .alpha.-amino acids of general formula (I) by continuous racemate splitting via diastereomeric salt pairs with re-racemisation of the residual amino acid or amino acid derivative in the mother liquid with the aid of an optically active acid.
摘要:
Disclosed is a process for producing .beta.-amino-.alpha.-hydroxycarboxylic acid derivatives of general formula (2R,3S)- or (2S,3E)-N-(X,Y)-3-amino-2-hydroxy-3-phenyl propionic acid-Z of Formula I, ##STR1## e.g. of (2E,3S)-3-amino-2-hydroxy-3-phenyl propionic acid or (2R,3S)-N-benzoyl-3-amino-2-hydroxy-3-phenyl propionic acid methylester. Compounds of type I are valuable intermediates in the total synthesis of Taxols which can be used in the treatment of various forms of cancer.
摘要:
A process for producing 2-�3(S)-amino-2-(R)-hydroxyl-4-phenyl butyl!-N-tert,butyl decahydro-(4aS,8aS)-isoquinoline-e(S)-carboxamide of the formula (I) via 3(S)-�lower alkoxy carbonyl amino, phenoxy carbonyl amino or benzyl oxycarbonyl amino!-2-hydroxy-4-phenyl butyric acid and process for producing said acid.
摘要:
N-substituted .alpha.-amino acids and dipeptides are valuable intermediate products for the production of inhibitors of the angiotensin converting enzyme (ACE); representatives are e.g. enalapril and ramipril. These compounds are prepared by means of hydrogenolytic conversion of a primary amine with a ketone with the addition of an organic or inorganic base; among the inorganic bases, basic aluminum oxide is preferred. The use of chiral organic bases favors the production of a diastereomer.
摘要:
Highly concentrated aqueous L-Tryptophan and/or L-Threonine salt solutions are used to supplement mixed feeds with L-Tryptophan and/or L-Threonine. They can be metered easily and accurately, can be produced in a highly concentrated form with a content of between 30 and 70% and are storage stable to a surprisingly high degree (slight tendency to crystallize, no chemical decomposition, no racemization) even over a relatively long period of at least three months when outside temperatures are low.
摘要:
Heavy metals can be precipitated from waste water or aqueous reaction solutions containing inorganic and/or organic complexing agents with substituted thiorureas of the general formula R.sub.1 R.sub.2 N-CS-NH-COR.sub.3. N,N-dialkyl-N'-benzoyl thioureas are used with preference, whereby methyl, ethyl, n-propyl or isobutyl groups are used as alkyl substituents.
摘要:
A novel route is described for the synthesis of N-methyl-3-hydroxy-3-(2-thienyl)propylamine IV, which can be used as a starting compound for the preparation of duloxetine. N-methyl-3-hydroxy-3-(2-thienyl)propylamine is synthesized via novel thiophene derivatives containing carbamate groups, I and IIa, as intermediates.