Abstract: The present invention relates to a process for the preparation of R- and S-lipoic acid and R- and S-dihydrolipoic acid comprising (a) reaction of where MS is SO2—R? and R and R? independently of one another are C1–C6-alkyl, C3–C8-cycloalkyl, C3–C8-cycloalkylalkyl, aryl or aralkyl, with sodium sulfide and sulfur in methanol. The invention especially relates to processes for preparing pure R- or S-dihydrolipoic acid, which is either used directly or processed further to give R- and S-lipoic acid. The process also serves for the production of pharmaceuticals. The present invention further relates to a solution of sodium sulfide trihydrate and sulfur in methanol, the sulfur being present in a molar excess over the sodium sulfide trihydrate, and a kit which comprises the solution according to the invention.

Abstract: The invention relates to a process for purifying lipoic acid, which comprises adding to a solution of lipoic acid at least 0.1 times the amount of an adsorbent, based on the mass of lipoic acid to be purified, and subsequently removing the adsorbent. It is possible in this way to provide racemic or nonracemic lipoic acid with an oligomer content below 1% by weight, for example from 0.1 to 1% by weight.

Abstract: Processes for the preparation of R-lipoic acid or S-lipoic acid comprising a process step selected from a) distillation of dihydrolipoic acid, b) reaction of ?or its stereoisomer, where Ms is SO2—R? and R and R? independently of one another is [sic] C1-C6-alkyl, C3-C8-cycloalkyl, C3-C8-cycloalkylalkyl, aryl or aralkyl, with sodium sulfide and sulfur in ethanol and reaction with a complex hydride, (c) the extraction of a protic solution of R-dihydrolipoic acid or S-dihydrolipoic acid with organic solvents at a pH from 9 to 10, or (d) the extraction of R-dihydrolipoic acid or S-dihydrolipoic acid with organic solvents from a protic solution at a pH of 4 to 5, or a combination of one or more of steps (a) to (d), and processes for the preparation of dihydrolipoic acid and the compound 1,6,8 [lacuna] octanetriol.

Abstract: The use of ?-lipoic acid or ?-dihydrolipoic acid for increasing the bioavailability of mineral salts, the use of ?-lipoic acid or ?-dihydrolipoic acid in combination with metal salts, in particular the use of metal ?-lipoates, metal ?-dihydrolipoates or metal-?-lipoic acid complexes, in particular in mineral preparations or drugs and the metal ?-lipoates, metal ?-dihydrolipoates or metal-?-lipoic acid complexes themselves are described.

Abstract: Processes for the preparation of R-lipoic acid or S-lipoic acid comprising a process step selected from

Abstract: The present invention relates to the use of lipoic acid, a physiologically acceptable derivative or salt thereof and one compound of the formula I

Abstract: A description is given of a process for preparing dihydroxycarboxylic esters and of an overall process for preparing R-(+)-&agr;-lipoic acid.

Abstract: A description is given of a process for preparing dihydroxycarboxylic esters and of an overall process for preparing R-(+)-&agr;-lipoic acid.

Abstract: In the 2 &THgr; diffractogram of an enantiomerically pure crystalline (R)- or (S)-lipoic acid, the most intense reflection line in the range from 13° to 30° is that at 2 &THgr;=23°.

Abstract: Enantiomerically pure &bgr;-hydroxy esters are prepared by a process in which &bgr;-keto esters are reacted with hydrogen in the presence of catalysts of the formula LRuX2 where X is halogen, acetate, allyl, methallyl, 2-phenylallyl, perchlorate, trifluoroacetate, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate, hexafluoroarsenate or trichloroacetate, L is a bidentate phospholane of the formula I  where B=a bridging link with 1-5 carbon atoms between the two phosphorus atoms, R1=H, C1-C6-alkyl, aryl, alkylaryl or SiR23, R2=alkyl or aryl, m=0 or 1, R3=H or OR4, and R4=R1, with the proviso that if m=1 then R3=H and if m=0 then R3 ≠ H.

Abstract: The use of &agr;-lipoic acid or &agr;-dihydrolipoic acid for increasing the bioavailability of mineral salts, the use of &agr;-lipoic acid or &agr;-dihydrolipoic acid in combination with metal salts, in particular the use of metal &agr;-lipoates, metal &agr;-dihydrolipoates or metal-&agr;-lipoic acid complexes, in particular in mineral preparations or drugs and the metal &agr;-lipoates, metal &agr;-dihydrolipoates or metal-&agr;-lipoic acid complexes themselves are described.

Abstract: The present invention relates to a process for preparing 3,5, 5-trimethylcyclohex -2-ene-1,4-dione (oxoisophorone; OIP) by oxidation of 3,5,5-trimethylcyclohex-3-en-1-one (&bgr;-isophorone, &bgr;-IP) with molecular oxygen in the presence of a solvent, of a base and of a manganese salen derivative as catalyst.

Abstract: The present invention relates to a process for preparing 3,5,5-trimethylcyclohex-2-ene-1,4-dione (oxoisophorone; OIP) by oxidation of 3,5,5-trimethylcyclohex-3-en-1-one (&bgr;-isophorone, &bgr;-IP) with molecular oxygen in the presence of a solvent, of a base and of a transition metal salen derivative as catalyst and of an additive.