Abstract: Unwanted sicklepod plants are controlled by subjecting the plants to an effective dosage of the (R.sup.*,S.sup.*)-(+)- optical isomer of 4-benzoyl-2,3-diphenylbutyric acid.

Abstract: Disclosed is a process for preparing an optical active alkyl ester of .alpha.-(6-methoxynaphth-2-yl)propionic acid from the racemic modification thereof or from a mixture of the optical isomers thereof by preferential crystallization. The efficiency of the optical resolution can be increased by adding a base which facilitates the racemization. The process comprises dissolving the racemic modification or the optical isomers in an organic solvent such as methanol, ethanol, etc., with or without a base such as sodium methoxide, sodium ethoxide, etc., and seeding seed crystals of one of the optical isomers to effect crystallization for optical resolution.

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: Racemic amino acids can be readily resolved by conversion to their diastereomeric esters of an optically active 2-isopropyl-5-methylcyclohexanol and separating the diastereomers by chromatography. It has been observed that the separation of the diastereomeric esters is relatively insensitive to the support or the solvent used as eluant. Thus, satisfactory separation occurs under a broad variety of conditions. The optically active amino acid can be obtained by base catalyzed hydrolysis of the purified diastereomer with high optical purity.

Abstract: A method for optical resolution of 2-(4-chlorophenyl)-3-methylbutanoic acid, which comprises crystallizing out the salt between (+) or (-)-2-(4-chlorophenyl)-3-methylbutanoic acid and diethylamine in a molar proportion of 2:1 predominantly from a super-saturated solution of the salt of 2-(4-chlorophenyl)-3-methylbutanoic acid with diethylamine, collecting the crystallized salt and decomposing the collected salt under acidic conditions to obtain the corresponding optically active acid.

Abstract: (.+-.)-2-Amino-1-butanol and/or (.+-.)-mandelic acid are optically resolved with a high resolution efficiency and high optical purities by preferentially crystallizing out one of the pair of less soluble enantiomeric salts (or optical antipodes), namely (+)-2-amino-1-butanol-(+)-mandelic acid salt and (-)-2-amino-1-butanol-(-)-mandelic acid salt.

Abstract: A process of separating cis and trans isomers of cyclopropane carboxylic acids comprising the step of treating an aqueous solution of a soluble salt of the cis and trans isomers with just sufficient of an acid, for example acetic acid or carbonic acid, to cause precipitation of one isomeric form of the cyclopropane carboxylic acid while substantially all or a major proportion of the other isomeric form remains in solution as the soluble salt. The process may be used, for example, to separate (+)-cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (an intermediate for insecticides) from a mixture of the (+)-cis and (+)-trans acids.

Abstract: A method for separation of diastereoisomeric 3-(3,4-dibenzyloxyphenyl)serine, which comprises reacting a mixture of the threo isomer and erythro isomer of 3-(3,4-dibenzyloxyphenyl)serine with a mineral acid and separating the mixture of the resulting mineral acid salts of the threo isomer and erythro isomer into each mineral acid salt by a conventional fractional crystallization utilizing the difference in solubility of the mineral acid salts, and optionally converting the separated mineral acid salt into a free isomer. Said 3-(3,4-dibenzyloxyphenyl)serine or a mineral acid salt thereof thus separated can give 3-(3,4-dihydroxyphenyl)serine which is a precursor of norepinephrine and which has activity in the circulatory system or psychotropic activities by removing the benzyl group therefrom.

Abstract: Processes for separating racemic trans-1,2-cyclic dicarboxylic acids by dissolving the racemic acid and a resolving agent such as cinchonidine in a solvent and cooling the solvent to form crystals rich in d-trans-1,2-cyclobutane dicarboxylic acid, the d-trans acid being recovered for use in preparing optically active materials.

Abstract: Two optically active amino acid-mandelic acid complexes are obtained by interacting in a solvent under pH conditions of 1.0-4.0 an amino acid expressed by a general formula ##STR1## (in which R represents a methyl group, an ethyl group or a methylthioethyl group) and mandelic acid, one of the acids being an optically active substance and the other being a racemic modification, and optically resolving the resulting complexes into two diastereoisomers by using solubility difference therebetween. The optically active complexes are each decomposed by means of an acid, a strongly acidic ion-exchange resin, or a weakly basis ion-exchange resin to obtain optically active amino acids or optically active mandelic acid.

Abstract: Disclosed is a process for increasing the proportion of a desired enantiomer of a 2-arylpropionic acid which comprises heating at a temperature of at least 80.degree. C. a mixture comprising an inert liquid organic diluent and a salt of the 2-arylpropionic acid with an enantiomer of a chiral organic nitrogenous base, the base and the diluent being such that the salt of the racemic acid has a solubility of 0.1 to 10% w/v in the diluent at the operating temperature and in which process a proportion of the salt is undissolved in the diluent, whereby a proportion of one optical isomer of the acid component of the salt is converted into its enantiomer, and collecting the salt of which the acid component has an increased proportion of that enantiomer.

Abstract: A method for isolating D and L amino acids from a racemic mixture of the formula(DL)--H.sub.2 N--CHX--COOY,and salts thereof, wherein X denotes an amino acid side chain and derivatives thereof and Y denotes a suitable alkyl group. The racemic mixture is contacted with water to form an aqueous solution. This aqueous solution is then contacted with an esterase to thereby obtain a solution comprising the resolved amino acids(L)--H.sub.2 N--CHX--COOH and(D)--H.sub.2 N--CHX--COOY.The N-terminus of the resolved (L) and (D) amino acids present in this solution are protected with an N-protecting group R to thereby obtain a solution comprising(L)--R--NH--CHX--COOH and(D)--R--NH--CHX--COOY.The isolation of (L)--R--NH--CHX--COOH from (D)--R--NH--CHX--COOY is achieved in high yields by an acid-base extraction.

Abstract: Two optically active amino acid-mandelic acid complexes are obtained by reacting in a solvent under pH conditions of 1.0-4.0, an amino acid expressed by a general formula ##STR1## (in which R represents a methyl group, an ethyl group or a methylthioethyl group) and mandelic acid, one of the acids being an optically active substance and the other being a racemic modification, and optically resolving the resulting complexes into two diastereomers by using a solubility difference therebetween. The optically active complexes are each decomposed by means of an acid, a strongly acidic ion-exchange resin, or a weakly basic ion-exchange resin to obtain optically active amino acids or optically active mandelic acid.

Abstract: A non-swellable three-dimensional polymer having a component which is a residue of an optically active compound, which residue is chemically removable from said polymer to leave behind in the physical structure of said polymer a void corresponding to the size and shape of said residue of optically active compound, and a particular steric arrangement of functional groups within the void of said polymer corresponding to the chemical structure of said residue of optically active compound, the original polymer having recurring units of the formulas ##STR1## wherein A, C and D are residues bonded to B of compounds which residues are polymerizable or polycondensable and B is a residue of an optically active compound; a process for preparing such polymer and the form of such polymer containing such void and free of the residue of optically active compounds.

Abstract: An aqueous solution of L-malic acid and potassium ion is prepared having a pH of no more than 6.8. The aqueous solution is cooled to initiate crystallization of a potassium salt of L-malic acid, and the aqueous mixture obtained is allowed to stand at a pH of 5.3 to 6.8 until it substantially reaches liquid-solid equilibrium. The resultant crystals of monopotassium L-malate monohydrate are collected therefrom. The monopotassium L-malate monohydrate thus obtained may be dried to give the corresponding anhydrate. Monopotassium L-malate and its monohydrate are stable, non-hygroscopic crystals.

Abstract: A process for the resolution of optical isomers of racemic lithium pantoate by selective crystallization from a solution in methanol, ethanol, or other polar solvents, or by electrostatic separation. The optical isomers can be readily converted to optically active pantolactones which are the starting material for the preparation of optically active pantothenic acid and its salt and pantothenyl alcohol. One of the two optical isomers of each of these compounds possesses vitamin activity. The unwanted or inactive optical isomer of lithium pantoate as such is thermally stable and can be racemized by heating in the presence of a basic reacting compound at a temperature between 120 and 180.degree. C to produce a racemic mixture which can then be subjected directly to resolution without conversion to some other derivative in accordance with the processes of the present invention to produce the desired or active optical isomer.

Abstract: DL- .alpha.-phenylglycine can be combined with benzene-sulfonic acid, p-ethylbenzenesulfonic acid or m-xylenesulfonic acid to give the salt. The salt of the racemate may be more soluble in a sulfuric acid solution than the salt of the optically active isomer by suitably choosing the concentration of the sulfuric acid solution, and then the optical resolution by fractional crystallization is carried out. The D- or L- .alpha.-phenylglycine sulfonate is easily liberated of the sulfonic acid portion to give optically active D- or L- .alpha.-phenylglycine.

Abstract: Chiral, hinged, asymmetric host binaphthyl-based multiheteromacrocycles of oxygen covalently bonded to styrene/divinylbenzene copolymers are provided. These new compounds have specific chiral recognition properties, which properties make these new compounds useful for separating or resolving racemic and other mixtures of amino acids, amino acid esters and salts thereof for either or both of analytical purposes or large scale manufacturing procedures.