Abstract: A method of isolating 1-[N2-((S)-ethoxycarbonyl)-3-phenylpropyl)-N6-trifluoroacetyl]-L-lysyl-L-proline (lisinopril (TFA) ethyl ester, LPE). The solvent or solvent mixture used for the extraction is also a main constituent of the solvent or solvent mixture from which the crystallization takes place. High yield as well as good purity of the end product are obtained, without distillation. 1-[N2-((S)-ethoxycarbonyl)-3-phenylpropyl)-N6-trifluoroacetyl]-L-lysyl-L-proline (lisinopril (TFA) ethyl ester, LPE) is described as a precursor for producing an ACE inhibitor.

Abstract: 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.

Abstract: There is provided a process for the work-up of this material having the formula ##STR1## because of its poor crystallizability has heretofore been available only with large yield losses. The yield losses are due to the fact that the crystals of this compound are associated with large amounts of residual solvent material which gives rise to complex and expensive drying procedures. In accordance with the present invention the crude LPE is dried by means of fluid or supercritical carbon dioxide which maces it possible to reduce drying times from the previous range of about 124 hours to about 10 hours for the same amount of product and thus produce a dry LPE which has smaller amounts of residual solvent, as well as smaller by-products than that obtained by conventional drying.

Abstract: 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.

Abstract: A method of isolating 1-?N.sup.2 -((S)-ethoxycarbonyl)-3-phenylpropyl)-N.sup.6 -trifluoroacetyl!-L-lysyl-L-proline (lisinopril (TFA) ethyl ester, LPE). The solvent or solvent mixture used for the extraction is also a main constituent of the solvent or solvent mixture from which the crystallization takes place. High yield as well as good purity of the end product are obtained, without distillation. 1-?N.sup.2 -((S)-ethoxycarbonyl)-3-phenylpropyl)-N.sup.6 -trifluoroacetyl!-L-lysyl-L-proline (lisinopril (TFA) ethyl ester, LPE) is described as a precursor for producing an ACE inhibitor.

Abstract: Method for the preparation of N-protected 4-ketoproline derivatives of formula I ##STR1## by oxidation of the corresponding N-protected 4-hydroxyproline derivatives of ##STR2## using the system TEMPO (2,2,6,6-tetramethylpiperidinyl oxy free radical)/NaOCl.