Abstract: A process for preparing alkynecarboxylic acids includes the oxidation of an alkyne alcohol with a hypohalite in the presence of a nitroxyl compound at a pH of greater than 7 with continual addition of the alkyne alcohol and of the hypohalite to the reaction mixture.

Abstract: Chiral secondary alcohols may be produced enzymatically in high space-time yields while minimizing enzyme use, by reducing a keto compound in an aqueous reaction medium containing water, reducing agent, alcohol dehydrogenase and coenzyme, extracting the secondary alcohol formed by means of a further phase containing a water-immiscible organic solvent, and removing the phase used for extraction and reusing the aqueous reaction medium in step a).

Abstract: A process for preparing ?-functionalized thiazolidines or oxazolidines, each of which are oxycarbonyl-functionalized in the 4-position, by adding a base to a reaction mixture comprising an oxycarbonyl-functionalized thiazolidine or oxazolidine and an electrophile at a temperature of greater than ?40° C.

Abstract: A process is provided for preparing optically active alcohols, amines and derivatives thereof by reacting aldehydes or imines at a temperature of less than 15° C. in the presence of a chiral, enantiomerically pure auxiliary with an organozinc halide which is obtained from zinc and a reactive halogen compound, and water, acid or base, or an alkylating, arylating, acylating or silylating reagent is subsequently added.

Abstract: A process for removing zinc from organic solutions comprising zinc alkoxides or zinc amides, includes admixing the solution with an alkylating, arylating, acylating or silylating agent in the presence of a precipitating reagent having at least two nitrogen donors and subsequently removing the precipitated solid.

Abstract: A process is provided for preparing an enantiopure 1,3-dioxolan-4-one or 1,3-oxathiolan-5-one derivative, which includes bringing a mixture containing enantiomeric 1,3-dioxolan-4-one or 1,3-oxathiolan-5-one derivatives and an enzyme with hydrolytic activity into contact in the presence of a nucleophile. Cleaving a dioxolanone/oxathiolanone ring of one enantiomer occurs by the enzyme with hydrolytic activity and, after the cleavage of one enantiomer has taken place, the uncleaved enantiomer of the 1,3-dioxolan-4-one or 1,3-oxathiolan-5-one derivative is isolated.

Abstract: Process for the enantioselective preparation of secondary alcohols, wherein a racemic or enantiomerically enriched mixture of acetoacetic esters of chiral secondary alcohols is subjected to enantioselective enzymatic solvolysis in the presence of a nucleophile and a lipase capable of the solvolytic cleavage of an ester group.

Abstract: A process for preparing &agr;-functionalized thiazolidines or oxazolidines, each of which are oxycarbonyl-functionalized in the 4-position, by adding a base to a reaction mixture comprising an oxycarbonyl-functionalized thiazolidine or oxazolidine and an electrophile at a temperature of greater than −40° C.

Abstract: A process is provided for preparing optically active alcohols, amines and derivatives thereof by reacting aldehydes or imines at a temperature of less than 15° C. in the presence of a chiral, enantiomerically pure auxiliary with an organozinc halide which is obtained from zinc and a reactive halogen compound, and water, acid or base, or an alkylating, arylating, acylating or silylating reagent is subsequently added.

Abstract: A process for removing zinc from organic solutions comprising zinc alkoxides or zinc amides, includes admixing the solution with an alkylating, arylating, acylating or silylating agent in the presence of a precipitating reagent having at least two nitrogen donors and subsequently removing the precipitated solid.

Abstract: A process for preparing alkynecarboxylic acids includes the oxidation of an alkyne alcohol with a hypohalite in the presence of a nitroxyl compound at a pH of greater than 7 with continual addition of the alkyne alcohol and of the hypohalite to the reaction mixture.

Abstract: A process for preparing alkynecarboxylic acids and alkyne alcohol esters of alkynecarboxylic acids, includes an oxidation reaction of an alkyne alcohol with from 1 to 10 molar equivalents of a hypohalite based on the number of functional groups to be oxidized in the presence of a nitroxyl compound at a pH of less than 7. There is also a partial oxidation reaction of the alkyne alcohol with from 0.5 to 5 molar equivalents of a hypohalite based on the number of functional groups to be oxidized in the presence of a nitroxyl compound at a pH of less than 7.

Abstract: A process for preparing organozinc halides in solvents, includes reacting a reactive halogen compound with zinc in one or more carboxylic esters. It is also possible to prepare keto, hydroxyl and amino compounds of organozinc halides obtained in a first step from a reactive halogen compound and zinc in one or more carboxylic esters, wherein the organozinc halide obtained is reacted in a second step with an electrophilic reaction partner and the reaction product of the second step is hydrolyzed in a third step.

Abstract: A process is provided for preparing an enantiopure 1,3-dioxolan-4-one or 1,3-oxathiolan-5-one derivative, which includes bringing a mixture containing enantiomeric 1,3-dioxolan-4-one or 1,3-oxathiolan-5-one derivatives and an enzyme with hydrolytic activity into contact in the presence of a nucleophile. Cleaving a dioxolanone/oxathiolanone ring of one enantiomer occurs by the enzyme with hydrolytic activity and, after the cleavage of one enantiomer has taken place, the uncleaved enantiomer of the 1,3-dioxolan-4-one or 1,3-oxathiolan-5-one derivative is isolated.

Abstract: A process for preparing organozinc halides in solvents, includes reacting a reactive halogen compound with zinc in one or more carboxylic esters. It is also possible to prepare keto, hydroxyl and amino compounds of organozinc halides obtained in a first step from a reactive halogen compound and zinc in one or more carboxylic esters, wherein the organozinc halide obtained is reacted in a second step with an electrophilic reaction partner and the reaction product of the second step is hydrolyzed in a third step.

Abstract: A process for precipitating cystine from a solution in sulfuric acid, includes forming a mixture of a solution of cystine in aqueous sulfuric acid and of an aqueous solution of a base by simultaneous metering the cystine solution and the aqueous base solution into a mixing container. The metering takes place in such a way that the mixture in the container has a pH between 1.0 and 7.0 and a temperature between 30° C. and the boiling point of the mixture.

Abstract: A process for precipitating cystine from a solution in sulfuric acid, includes forming a mixture of a solution of cystine in aqueous sulfuric acid and of an aqueous solution of a base by simultaneous metering the cystine solution and the aqueous base solution into a mixing container. The metering takes place in such a way that the mixture in the container has a pH between 1.0 and 7.0 and a temperature between 30° C. and the boiling point of the mixture.

Abstract: Multi-component system for modifying, degrading or bleaching lignin, lignin-containing materials or similar substances, includes

Abstract: Multi-component system for modifying, degrading or bleaching lignin, lignin-containing materials or similar substances, includes (a) if appropriate at least one oxidation catalyst; (b) at least one suitable oxidizing agent; and (c) at least one mediator, wherein the mediator is chosen from the group consisting of N-aryl-N-hydroxyamides.

Abstract: A multicomponent system for modifying, degrading or bleaching lignin and lignin-containing materials or similar substances, includes an oxidoreductase and an oxidant suitable for the oxidoreductase and a mediator and at least one enzymatically active additive. The mediator does not inactivate the oxidoreductase and the enzymatically active additive, and the enzymatically active additive is selected from the group consisting of the hydrolases of the enzyme class 3.2.1.