摘要:
A process employs amidine or amidine base and a metal compound in the presence of an alcohol or water to transesterify, or saponify esters or amides. Since the process employs relatively mild conditions, it is especially suitable for the production of optically active substances and biomolecules, e.g. peptides, amino acids and nucleic acids which are sensitive to elevated temperatures, extreme pH values and/or long reaction times since these compounds are easily racemised or denatured. The conditions additionally find use in solid phase systems. When amino acid or peptide esters are saponified, the splitting is brought about with lithium hydroxide alone under mild conditions. The use of an amidine base, more particularly DBU or DBN, in combination with the metal salt additionally accelerates the reaction so strongly that even sensitive acid derivatives can be reacted under mild conditions. The amidine based system lends itself to the manufacture of complex esters, gentle splitting of peptides from the carrier, gentle saponification of amides or esters.
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 is disclosed by which N-carbamoyl-(R)-tert.-leucine is obtained from tert-butyl hydantoin by means of an (R)-specific hydantoinase, in which N-carbamoyl-(R)-tert.-leucine is converted by reaction with nitrite or an (R)-carbamoylase to (R)-tert-leucine.
摘要:
A process is disclosed for reducing amino acids and derivatives thereof Compounds of formula (I), in which n=0 or 1 and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 have the meanings given in the description, are reduced to the corresponding amino alcohols of formula (II): the formula (I) compounds are converted in a first step, in at least one alcohol and with the addition of acid and heat to an ester, this process producing a reaction mixture containing the ester; the ester is converted in a second reaction step with alkali or alkaline earth borohydride to compounds of formula II. By specifying that the second step be carried out without isolating the ester from the reaction mixture and by using alkali or alkaline earth borohydrides which are not activated, the invention facilitates the production from amino acids and their derivatives of the correponding alcohols in a simple "single vessel" process, with high yields and in such a way as to preserve a given centre of chirality. Applications: synthesis components, preparation of optically active compounds splitting of racemic compounds. ##STR1##
摘要:
A process for purifying 1-[N.sup.2 -((S)-ethoxycarbonyl)-3-phenylpropyl)-N.sup.6 -trifluoroacetyl]-1-lysyl-1-proline by extraction and crystallization. The process includes a two step extraction in a two phase aqueous/organic solvent system and crystallization from organic solvent.
摘要:
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.
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:
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:
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.
摘要:
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.