摘要:
2.2. 1,3-imidazolidine-4-ones having the General Formula: ##STR1## are obtained in a pure form especially by means of precipitation, in which production an optically active acid can be used at 0.5-0.8 eq. for the separation of racemates. The non-desired enantiomer can be racemized in an inert solvent and the cyclization to imidazolidinone can take place by means of the optically active acid, whereupon the separation of racemates takes place directly thereafter. 1,3-imidazolidine-4-ones are valuable educts for the preparation of branched or unbranched, proteinogenic or non-proteinogenic .alpha.-amino acids by means of diastereoselective alkylation and subsequent ring splitting.
摘要:
A method of producing optically active pyrrolidines of the general formula ##STR1## in which R.sup.1 is hydrogen or OH,R.sup.2 is a benzyl group which can have one or more alkyl-, alkoxy- and/or halogen substituents on the aromatic, and* is and/or can be an asymmetric center,by reducing the corresponding, enantiomerically pure pyrrolidinediones using activated alkali boron hydride.
摘要:
A method of producing optically active tert-leucinol (formula I) of high enantiomeric purity ##STR1## by converting racemic (RS)-tert-leucinol into a diastereomeric salt pair by reaction with an optically active acid, removing the salt pair from solution by fractionated crystallization and separating therefrom the optically active acid to release the optically active tert-leucinol from the salt. The optically active acid used is an N-acylated tert-leucine of general formula VIII: ##STR2## in which R can be hydrogen or an alkyl-, arylalkyl- or aryl group with up to 20 C atoms and * signifies a chirality center.
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.
摘要:
A plant peptide amidase from the flavedo of oranges is known; this can be obtained only in small quantities and is seasonal. The proposed new enzymes are microbial peptide amidases which can be obtained from micro-organisms recovered from soil samples in a “double screening” and grown. These microbial peptide amidases are particularly useful for (a) the production of peptides and N-terminal-protected amino acids, (b) racemate splitting of N-protected amino acid amides, (c) obtaining non-proteinogenous D-amino acids, and (d) obtaining new N&agr;-protected D-amino acid amides.
摘要:
A plant peptide amidase from the flavedo of oranges is known; this can be obtained only in small quantities and is seasonal. The proposed new enzymes are microbial peptide amidases which can be obtained from micro-organisms recovered from soil samples in a "double screening" and grown. These microbial peptide amidases are particularly useful for (a) the production of peptides and N-terminal-protected amino acids, (b) racemate splitting of N-protected amino acid amides, (c) obtaining non-proteinogenous D-amino acids, and (d) obtaining new N.sub..alpha. -protected D-amino acid amides.
摘要:
The present invention relates to specific Escherichia. coli mutants which can be used for the synthesis of D-amino acids, and to such a process. The mutants are distinguished by deficiencies in particular enzymes which break down D-amino acids and include those which produce D-amino acids via the carbamoylase/hydantoinase route.
摘要:
The present invention relates to a process for the preparation of &ggr;-lactams of the general formula I The invention relates also to novel advantageous intermediates of the general formulae V, IV and II and their salts and their use. The compounds of the general formula I are obtained by cyclising compounds of the general formula II which can be prepared from the intermediate compounds V.
摘要:
.alpha.-oximino carboxylic acids or their esters are reduced with an alkali boron hydride and hydrogen chloride or sulfuric acid to yield racemic amino alcohols (e.g. (RS)-tert-leucinol).
摘要:
Escherichia. coli mutants which can be used for the synthesis of D-amino acids, and to such a process. The mutants are distinguished by deficiencies in particular enzymes which break down D-amino acids and include those which produce D-amino acids via the carbamoylase/hydantoinase route.