Abstract: An optically active acetylene polymer which is obtained by polymerizing an optically active form of 1-[dimethyl(10-pinanyl)silyl]-1-propyne which is represented by the following formula (I) and has a weight-average molecular weight of from 10,000 to 1,000,000, a membrane comprising this optically active acetylene polymer as the main component and a method for optically resolving a mixture of optical isomers by using this membrane: ##STR1##

Abstract: Process for transforming (benzoyl-3-phenyl)-2-propionic-R(-) acid into an S(+) isomer through the action of a base either in situ during the splitting of racemic ketoprofen or on the crystallization mother liquor of a (benzoyl-3-phenyl)-2-propionic-S(+) acid salt.

Abstract: Optically-active, amphiphilic, free-radical addition copolymers having an optically-active hydrophobic portion and an ionic hydrophilic portion are effective resolving agents. This utility is based on a unique combination of properties, viz., water solubility, chirality and amphiphilicity, i.e., having a dual hydrophobic and hydrophilic nature.

Abstract: (.+-.)-2-(4-Isobutylphenyl)-propionic acid can be resolved into optically active isomers easily and with high yields. The method is characterized by the use of the optically active amine of the following general formula (I) or (II) as a resolving agent.

Abstract: The present invention relates to a process for the preparation of optically active amino acid amide. L-amino and D-amino acid amides are mixed in the presence of 0.5-4 equivalents of an aldehyde, relative to the quantity of amino acid amide, in the presence of a solvent and water. The mixture is converted in whole or in part by means of an optically active carboxylic acid into a salt of the amino acid amide and the carboxylic acid. A portion mainly consisting of one of the diastereoisomers of that salt is separated from the reaction mixture obtained. Instead of a mixture of L-amino and D-amino acid amides, it is also possible to use a mixture of the Schiff bases of an amino acid amide and an aldehyde, in which case it is not necessary to add extra aldehyde, and the required quantity of water amounts to at least 1 equivalent relative to the quantity of Schiff base. With this process, a high yield of optically active amino acid amide or the corresponding amino acid is rapidly obtained.

Abstract: D(+)-threo-2-hydroxy-3-(2-aminophenylthio)-3-(4-methoxyphenyl)propionic acid, an important intermediate in the synthesis of diltiazem hydrochloride, is obtained in better yields and high optical purity by a novel resolution process comprising the reaction of 2 moles of the (.+-.) racemic acid with 1 mole of quinine and 1 mole of a base in a suitable polar solvent system to form a salt of the D(+) acid and quinine which precipitates; separating said salt and decomposing it with a strong base.

Abstract: A process is disclosed that is useful for separating the enantiomers of a racemic mixture of an aliphatic carboxylic acid having the formula ##STR1## where R.sub.1 is hydrogen or alkyl, R.sub.2, R.sub.3 and R.sub.4 are independently different and are hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, phenyl, substituted phenyl, naphthyl, substituted naphthyl, heteroaryl, substituted heteroaryl, haloalkyl, alkoxyalkyl, alkylthioalkyl, phenylalkyl, substituted phenylalkyl, heteroalkylalkyl, substituted heteroalkylalkyl or cycloalkylalkyl.

Abstract: The invention provides a process for preparing single enantiomers of compounds represented by the formula: ##STR1## and chiral acid addition salts thereof; wherein: X and Y are independently hydrogen; lower alkyl; lower alkoxy; or halo; or X and Y taken together is methylenedioxy or ethylene-1,2-dioxy;which includes reduction of a compound represented by the formula: ##STR2## to give a mixture of stereoisomers represented by the formula: ##STR3## wherein each wavy line independently represents a bond in either the .alpha. or .beta. position;followed by dissolving the mixture of stereoisomers and a chiral resolving acid in a suitable solvent and allowing the solution to crystallize, giving a salt of the desired enantiomer.

Abstract: The invention relates to a process for the preparation of S(+)-6-methoxy-.alpha.-methyl-2-naphthalene-acetic acid by resolution of R,S-6-methoxy-.alpha.-methyl-2-naphthalene-acetic acid. According to the invention R,S-6-methoxy-.alpha.-methyl-2-naphthalene-acetic acid and R(-)-2-amino-1-butanol are dissolved in water at 40.degree.-60.degree. C. Then the solution thus obtained is cooled to 25.degree.-35.degree. C. Subsequently the obtained solution is grafted with a salt of S(+)-6-methoxy-.alpha.-methyl-2-naphthalene-acetic acid and R(-)-2-amino-1-butanol, further it is cooled to 5.degree.-15.degree. C. The thereby formed crystals are separated from the solution and washed with water and subsequently hydrolyzed by adding a strong acid, whereby S(+)-6-methoxy-.alpha.-methyl-2-naphthalene-acetic acid crystallizes and the obtained crystals are separated from the mother liquor and the R(-)-6-methoxy-.alpha.

Abstract: A process for the kinetic resolution of cis or trans enantiomeric mixtures of the compounds of formula ##STR1## wherein R.sub.3 and X have the meanings reported in the specification and the asterisks mark the asymmetric carbon atoms, is described.The compounds of formula III-A are intermediates useful in the preparation of compounds active on the cardiovascular system.

Abstract: A method of separating isomers of functionalized aromatic compounds using solvent-modified supercritical carbon dioxide is disclosed and claimed. In one embodiment, isomers of hydroxynaphthoic acid are separated by selective extraction of the more soluble species.

Abstract: Optical resolution of (.+-.)-2-(3-benzoyl)-phenylpropionic acid is attained effeciently in high yield by the use of a specific optically active amine which is represented by the general formula [I]: ##STR1## wherein R.sup.1 either stands for a hydrogen atom, a chlorine atom, a bromine atom, a methyl group, or an isopropyl group or participates, as a divalent group, in forming a benzene ring in combination with two carbon atoms adjoining each other in a benzene ring to which the substituent, R.sup.1, is bonded, R.sup.2 stands for a lower alkyl group, a hydroxymethyl group, an .alpha.-hydroxybenzyl group, or a ##STR2## group (R.sup.3 standing for a hydrogen atom, a chlorine atom, a bromine atom, or a methyl group), n for 0 or 1, and * for the center of optical activity.

Abstract: A process for obtaining a substantially pure enantiomer of ibuprofen is described. The process utilizes first an enantiomerically enriched mixture of ibuprofen obtained from kinetic resolution, diastereomeric crystallization or asymmetric synthesis processes. This enriched mixture is dissolved in a solvent and solid racemic ibuprofen is separated, leaving a mother liquid comprising the solvent and the enriched enantiomer substantially free of the other enantiomer.

Abstract: The present invention relates to a process for the separation of the enantiomers of threo-2-hydroxy-3-(2'- aminophenylthio)-3-(4"-methoxyphenyl)-propionic acid, which is an important intermediate in the synthesis of pharmacologically active compounds, by means of the direct crystallization of the relevant cyclohexylaminic salt.According to a preferred form of practical embodiment of the present invention, the optically pure acid is recovered as the hydrochloride of the corresponding methyl ester.

Abstract: The novel (S)-4-(2-bromobenzoyl)-5-hydroxy-benzocyclobutene-1-carboxylic i.e. the compound of the formula ##STR1## in free form or in salt form, can be used as active ingredient in pharmaceutical preparations and can be prepared by a novel process, which is characterized in that racemic 4-(2-bromobenzoyl)-5-hydroxy-benzocyclobutene-1-carboxylic acid is reacted at elevated temperature with at least the equimolar amount of quinine in an alcoholic solvent for from approximately 6 to approximately 48 hours, the quinine salt of the (S)-4-(2-bromobenzoyl)-5-hydroxy-benzocyclobutene-1-carboxylic acid, precipitated in crystalline form as the direct reaction product, is separated from the reaction mixture, and the (S)-4-(2-bromobenzoyl)-5-hydroxy-benzocyclobutene-1-carboxylic acid is set free from this salt by acid treatment in a customary manner, and, if desired, this free acid is converted into a salt.

Abstract: The enantiomers of 2,2-dimethylcyclopropanecarboxylic acid are separated by salt formation with optically active 1-(3-methoxyphenyl)-ethylamine, fractional crystallization of the diastereomeric salts and subsequent decomposition of the salts with a strong acid.

Abstract: Novel substituted lactones of amino acids in all their possible stereoisomeric forms or mixtures thereof of the formula ##STR1## wherein A is a hydrocarbon chain of 1 to 10 chain members containing one or more heteroatoms and one or more unsaturations and the chain members being a mono- or polycyclic system or comprises a system of spiro or endo type and may contain one or more chiral atoms or the lactone copula can present a supplementary chirality due to the asymetric spatial configuration of the molecule make up and R is selected from the group consisting of ##STR2## wherein Z is the organic remainder of an amino acid of the formula ##STR3## Y is derived from a primary, secondary or tertiary alcohol of the formula Y-OH and B is the remainder of a heterocycle amino acid of 3 to 6 carbon atoms of the formula ##STR4## and their preparation and their use for the resolution of amino acids.

Abstract: A process of spontaneous resolution of compounds of formula ##STR1## wherein R has the meanings reported in the description, is described. The compounds of formula III are intermediates useful for the preparation of Diltiazem.

Abstract: A process for the optical resolution of 2-hydroxy-3-(4-methoxyphenyl)-3-(2-acetylaminophenylthio)-propionic acid sodium salt by seeding of a supersaturated solution of said salt with one of the enantiomers.

Abstract: Novel fluorescent chiral derivatization reagent containing a compound of the formula: ##STR1## being useful for the determination of carboxylic acid enantiomers with high sensitivity, which are easily and well separated in a form of their consequent diastereomeric amides.

Abstract: A process is disclosed for the formation and resolution of (S)-ibuprofen-(S)-lysine. The process employs preferential crystallization to separate a pair of diasteromeric salts, (S)-ibuprofen-(S)-lysine and (R)-ibuprofen-(S)-lysine.

Abstract: A process is described in which a mixture of enantiomeric arylpropionic acid is split and one of enantiomeric forms of the acid is recovered. The mixture is transformed into a diastereoisomeric salt by a reaction with a chiralic base and an inert solvent, and the desired acid enantiomer is removed from the reaction product. The transformation to a diastereoisomeric salt takes place in a polar solvent. The salt produced is recrystallized several times and the thus purified salt is split in a dilute mineral acid.

Abstract: The invention refers to a process for the preparation of L(-)carnitine by using dibenzoyl-D(31 )tartaric acid and crystallizating the relative salt at low temperature.

Abstract: A process for the optical resolution of 2-hydroxy-3-(4-methoxyphenyl)-3-(2-acetylaminophenylthio)-propionic acid sodium salt by seeding of a supersaturated solution of said salt with one of the enantiomers.

Abstract: The optical purity of an optically active 2-(4-aryloxyphenoxy)propionic acid is enriched by formation of the hydrate of the enantiomer in excess and its removal from solution.

Abstract: Diastereomers can be separated with good industrial success with the aid of extractive distillation. The separation process is characterized in that an auxiliary which changes the partial pressure of the various diastereomers to be separated to a different degree and thus allows easier separation of the diastereomers by distillation is added during the distillation. Using the present process diastereomic cis/trans-permetric acid methyl esters and mixtures of menthol and isomenthol can be separated with isolation of 99% pure product.

Abstract: A process for the optical resolution of 2-(6-methoxy-2-naphthyl)propionic acid by seeding a supersaturated solution of the ethylamine salt of said acid.

Abstract: The invention relates to a process for the kinetic resolution of D,L-racemic mixtures of racemates crystallizing as conglomerates. Resolution is effected from supersaturated solutions of these which is carried out in the presence of a polymer bound inhibitor of crystallization of the one form, resulting in the preferred crystallization of the one form, and when the other form is desired - in the presence of such inhibitor for the other form. Amongst racemic mixtures amenable to this process are amino acids. The process can be carried out in a two-compartment device, where the compartments are separated by a membrane which is permeable to the constituents of the racemate, while it is impervious to the polymer-bound inhibitor for the crystallization of one of the racemic forms.

Abstract: Racemic carboxylic acids are resolved into their enantiomers using optically active enantiomers of four lactones as resolving agents. The four lactones are 2,3-isopropylidene-ribonic acid-1,4-lactone, 1,2-isopropylidene-glucofuranurono-3,6-lactone, 2-hydroxy-3,3-dimethyl-1,4-butyrolactone and 3,4-isopropylidene-arabino-1,5-lactone. Novel diastereoisomeric esters of the acids with the lactones are disclosed.

Abstract: A method for the isolation of a substantially pure L-isomer of an amino acid from its D,L racemic mixture does not require the use of a resolving agent, the formation of a derivative of the amino acid or additional enzymic reactions.The method is based upon the concept of the equal saturation point wherein the L-isomer can be separated from the D-isomer by precipitation of the L-isomer when the relative concentration of the D-isomer is less than 7.0% or by precipitation of the D,L racemate when the relative concentration is greater than 7.0%. Selective crystallization through seeding allows for further isolation of pure L-isomer when its relative concentration in solution is very low.

Abstract: A method for optically resolving (.+-.)-cis or (.+-.)-trans-permethric acid which comprises reacting (.+-.)-cis-permethric acid and optically active 1-(p-tolyl)ethylamine or optically active cis-N-benzyl-2-(hydroxymethyl)cyclohexylamine, or reaction (.+-.)-trans-permethric acid and optically active 1-(p-isopropylphenyl)ethylamine, optically active 1-ethylbenzylamine or optically active cis-N-benzyl-2-(hydroxymethyl)cyclohexylamine.

Abstract: A method for the chromatographic resolution and analysis of the enantiomers of 2-(phenyl or phenoxy)propionic acids or the C.sub.1 -C.sub.4 alkyl esters thereof which comprises converting a racemic or partially resolved mixture of said 2-(phenyl or phenoxy)propionic acids or the C.sub.1 -C.sub.4 alkyl esters thereof to a pair of diastereomeric 2-amino-1-alkanol derivatives by reaction with an optically active 2-amino-1-alkanol, and analyzing the diastereomeric mixture by gas chromatography.

Abstract: Alpha-isopropyl-p-chlorophenylacetic acid, which is an acid moiety of the pyrethroidal ester pesticides is subjected to optical resolution using optically active alpha-phenyl-beta-p-tolylethylamine or optically active alpha-phenylethylamine, as the optical resolution agent. The reaction of the acid with the amine is carried out in a hydrophobic organic solvent, such as aliphatic and aromatic hydrocarbons, in the presence of water, until the desired salt of the acid with the amine is separated therein through selective crystallization.

Abstract: Hydrochloric acid is added to a solution containing L-cysteine, L-cystine, L-serine and an inorganic salt until it contains at least 15% by weight of hydrochloric acid. The solution is held at a temperature of at least 20.degree. C. so that the L-cystine and the inorganic salt may form a solid, and the solid is removed from the solution. The solution is cooled to a temperature not exceeding 10.degree. C., so that crystallization may take place to form the monohydrate of L-cysteine hydrochloride. The monohydrate is separated from the L-serine in the solution.

Abstract: A new process for the optical resolution of racemic mixtures of .alpha.-naphthylpropionic acids of formula ##STR1## wherein R.sub.1 is (C.sub.1-6) alkyl and R.sub.2 represents hydrogen or a halogen atom comprises reacting a racemic mixture of a compound of formula II ##STR2## wherein R.sub.1 and R.sub.2 have the above seen meanings and R.sub.3 is a reactive group, with an optically active aminoacid of formula ##STR3## wherein R.sub.4 represents a (C.sub.1-8) alkyl, phenyl, substituted phenyl, benzyl, substituted benzyl or carboxy, and m is an integer from 0 to 4, to give a pair of diastereoisomeric amides of formula ##STR4## wherein R.sub.1, R.sub.2, R.sub.4 and m have the above seen meanings, and M is a hydrogen atom or a cation of an alkali metal or a cation of an organic base. Compounds IV are resolved into the single diastereoisomeric amides d,d or 1,d, or d,1 or 1,1. Acid hydrolysis gives the optically active compound I.

Abstract: This invention relates to a process for producing optically active valine, characterized by optically resolving DL-valine hydrochloride in a solvent containing an amine salt, a sulfonic acid or a carboxylic acid and isolating optically active valine after the decomposition of the obtained optically active valine hydrochloride.

Abstract: The present invention relates to the separation of optically active phenylalanine and N-acyl derivatives thereof and novel diastereomer salts of the said compounds.According to the invention a racemic compound of the formula ##STR1## is reacted with an optically active resolving agent of the formula ##STR2## in a polar solvent and/or a mixture of solvents comprising at least one apolar solvent and optionally an achiral acid or base, thereafter(a) when using the D-isomer of the resolving agent of the formula II, the crystalline diastereomer salt formed with the L-isomer of the compound of the formula I is separated, or(b) when using the L-isomer of the resolving agent of the formula II, the crystalline diastereomer salt formed with the D-isomer of the compound of the formula I is separated, andthe enantiomers of the compound of the formula I from the diastereomer salt or the mother liquor are liberated by the aid of an achiral acid or base and the optically active product is separated in crystalline form.

Abstract: A process for the optical resolution of racemic mixtures of .alpha.-naphthyl-propionic acids of formula I ##STR1## which consists of reacting a racemic mixture of a compound of formula II ##STR2## with an optically active compound of formula IIIR.sub.4 --NH.sub.2wherein R.sub.4 is the residue of a primary or secondary alcohol which, taken with the NH.sub.2 radical, forms an optically active .beta.-aminoalcohol, to give a pair of diastereoisomeric amides, which is resolved into the single diastereoisomeric amides. Acid hydrolysis gives the optically active d or l .alpha.-naphthyl-propionic acids. The meaning of R.sub.1, R.sub.2, R.sub.3 is given.

Abstract: Disclosed is a method of optical resolution of DL-cysteine utilizing optically active mandelic acid. The method facilitates commercial production of optically active cysteine, particularly L-cysteine which is in great demand.

Abstract: Novel octopine derivatives are disclosed which are useful for the selective growth of the agriculturally useful A. tumefaciens bacterium along with a synthetic method for their preparation. Also disclosed is a method of separating octopine derivatives from their diastereoisomers along with a method of selectively growing strains of the bacterium A. tumefaciens.

Abstract: A process for the optical resolution of DL-cysteine which comprises(1) converting DL-cysteine into a hydrochloride thereof and forming a saturated or supersaturated aqueous solution thereof,(2) inoculating the solution with crystals of one optically active form of cysteine hydrochloride as seed crystals, and(3) preferentially crystallizing optically the same form of the cysteine hydrochloride used as the seed crystals, in a state of a monohydrate thereof.

Abstract: Optically active compounds having a chlorine atom attached to the chiral carbon atom such as 2-bromoaliphatic acids can be racemized without by-product formation by heating an acidified solution of the organic acid at a temperature sufficient to accomplish racemization, the solution being substantially devoid of ionized halogen other than bromine ions. The preferred acidifying agent is hydrobromic acid. The use of hydrochloric acid causes extensive by-product formation.

Abstract: Optically active compounds having a chlorine atom attached to the chiral carbon atom such as 2-chloroaliphatic acids can be racemized without by-product formation by heating an acidified solution of the compound in the presence of chloride ion at sufficient strength, and at a pH and temperature sufficient to accomplish racemization. The preferred acidifying agent and source of chloride ion is hydrochloric acid. The use of hydrochloric acid at room temperature as well as the use of either sulfuric acid or caustic soda failed to produce racemization.

Abstract: The invention relates to a new process for separating the four stereoisomers of the cyclopropanecarboxylic acids of the formula ##STR1## wherein R stands for a methyl group or a halogen atom.

Abstract: Methods and compositions are provided for asymmetrically donating an oxygen atom to a pair of electrons to produce an asymmetric product. Specifically, a metal alkoxide is used as a catalyst, where the metal has a coordination number of at least four, and at least one, usually two, of the alkoxide groups bonded to the metal are bonded to asymmetric carbon atoms. The metal catalyst is employed in conjunction with a hydroperoxide and an alkanol having a functionality with a pair of electrons capable of accepting an oxygen atom. The resulting product is enriched in one enantiomer due to the enantioselective introduction of an asymmetric center or an enhanced rate of reaction of one of the enantiomers of a chiral alkanol.

Abstract: This invention relates to a process for producing optically active phenylalanine, characterized by optically resolving DL-phenylalanine.optically active mandelic acid complexes in an aqueous solvent in the presence of an acidic compound having a pKa value of 0.90 to 2.10 and isolating optically active phenylalanine from the obtained optically active phenylalanine.optically active mandelic acid complex.According to the process of the present invention, it is possible to decrease the amount of a mother liquor of resolution to 1/5 to 1/10 of that when no acidic compound is used and to obtain optically active phenylalanine having an optical purity of as high as 96.5% or above without a step of optical purification when optically active phenylalanine is isolated from the obtained optically active phenylalanine.optically active mandelic acid complex.

Abstract: The subject matter of the invention is a process for the recovery of S-(carboxymethyl)-(R)-cysteine and S-(carboxymethyl)-(S)-cysteine from a mixture of the two enantiomers. The mixture to be separated is dissolved in water in the presence of sufficient ammonia that the ammonium salt solution formed has a pH between 6 and 9. Then there is brought about in the solution of ammonium salt a state of supersaturation by the addition of seeding crystals of the ammonium salt of one of the two enantiomers, insofar as the starting material contains one of the two enantiomers in excess, the ammonium salt of this enantiomer, the ammonium salt of one of the two enantiomers is brought to crystallization and separated off. Subsequently by addition of seeding crystals of the ammonium salt of the other enantiomers to the remaining mother liquor the ammonium salt of this enantiomer is likewise brought to crystallization and separated off.

Abstract: A process for resolution of a mixture of D- and L- amino acids, selected from threonine (THR), asparagine (ASN), p-hydroxyphenylglycine p-toluene sulfonate (pHPGpTS) and glutamic acid hydrochloride (GLU), which crystallize in the form of a conglomerate, whereby the ratio of one desired enantiomorph to the other undesired enantiomorph of said amino acid is increased in the crystalline compound obtained, as compared to the ratio in the starting material, which process comprises forming a supersaturated solution of said mixture, adding another predetermined amino acid as additive, which has a molecular structure which resembles that of one of the enantiomers of said racemic mixture, said additive being a D-amino acid as an inhibitor of the growing D-amino acid when the L-amino acid is desired, or a L-amino acid when the D-amino acid is desired, and crystallizing part of the compound from said supersaturated solution. When GLU.

Abstract: Methods and compositions are provided for asymmetrically donating an oxygen atom to a pair of electrons to produce an asymmetric product. Specifically, a metal alkoxide is used as a catalyst, where the metal has a coordination number of at least four, and at least one, usually two, of the alkoxide groups bonded to the metal are bonded to asymmetric carbon atoms. The metal catalyst is employed in conjunction with a hydroperoxide and an alkanol having a functionality with a pair of electrons capable of accepting an oxygen atom. The resulting product is enriched in one enantiomer due to the enantioselective introduction of an asymmetric center or an enhanced rate of reaction of one of the enantiomers of a chiral alkanol.

Abstract: The invention is directed to optically active proline derivative of the general formula: ##STR1## in which X is a hydrogen atom or a hydroxyl group and R is a hydrogen atom, an unsubstituted or alkyl group substituted phenyl group or a straight chain or branched alkyl group having 1 to 20 carbon atoms and a process for its production by reacting an enantiomerically pure proline or 4-hydroxy-proline as a solution in an alkanol having 1 to 4 carbon atoms with 0.9 to 2 times the molar amount of an alkali metal alcoholate corresponding to the alkanol and 1 to 3 times the molar amount of an epoxide of the general formula ##STR2## in which R is as defined above. The optically active proline derivative of general formula (I) can be used in the form of metal ion chelate complexes as the chiral stationary phase in the separation of enantiomers by means of liquid chromatography.