Abstract: A process for preparing and concentrating (6S,?S) or (6S,?R) tetrahydrofolic acid ester salts and (6S,?S) or (6S,?R) tetrahydrofolic acid, characterized by preparing or dissolving equimolar or concentrated mixtures of diastereomers of addition salts of tetrahydrofolic acid esters with aromatic sulphonic acids in organic solvents, followed by crystallizing them at least once, and then if applicable hydrolyzing the crystallizate to produce (6S,?S) or (6S,?R) tetrahydrofolic acid, crystallizing the latter as a free acid or isolating it in the form of a salt.

Abstract: The invention relates to the use of at least folic acid or a folate and tetrahydrobiopterin (BH4) or derivatives thereof for treating or preventing cardiovascular or neurological disorders by modulation of the activity of nitric oxide synthase (NOS).

Abstract: Pure and extremely stable crystalline (6R)-tetrahydrofolic acids, absolutely inert even when exposed to air and elevated temperature without stabilizers being added, are prepared by a crystallization process at a pH of ≧2.

Abstract: This invention relates to stable crystalline salts of 5-methyl-(6R,S)-, -(6S)- and -(6R)-tetrahydrofolic acid, to methods of producing these salts and to the use thereof use as a constituent for the production of drugs or as a food additive, and to preparations containing these salts.

Abstract: Pure and extremely stable crystalline (6S)- and (6R)-tetrahydrofolic acids, absolutely inert even when exposed to air and elevated temperature without stabilizers being added, are prepared by a crystallization process at a pH of ≧3.5 for the preparation of crystalline (6S)-tetrahydrofolic acid and at a pH of ≧2 for the preparation of crystalline (6R)-tetrahydrofolic acid.

Abstract: This invention relates to the use of tetrahydrofolates in natural stereoisomeric form for the production of a pharmaceutical preparation suitable for influencing the homocysteine level, particularly for assisting the remethylation of homocysteine. Clinical areas of application include all anomalies of the homocysteine level, particularly the prevention and treatment of cardiovascular diseases and the prevention of neural tube deficiencies.

Abstract: This invention relates to stable crystalline salts of (6R,S)-, (6S)- and (6R)-tetrahydrofolic acid, to methods of preparing these salts and to their use as an ingredient for the production of drugs and pharmaceutical preparations.

Abstract: The invention relates to a process for preparing (6S)-folinic acid and its salts by recrystallization of alkaline-earth salts of (6R,S)-folinic acid and, where necessary, liberation of the acid from the alkaline-earth folinates and/or, where necessary, conversion into the alkali salts by at least one recrystallization in the presence of a base.The invention also relates to calcium-, magnesium-, potassium- and sodium-(6S)-folinates and to (6S)-folinic acid prepared in accordance with the invention.

Abstract: A method for the resolution of (6R,S)-folinates into their diastereomers, comprising adding a water-soluble alkali metal, ammonium or alkaline earth metal salt of an inorganic or organic acid to an aqueous solution of a salt of (6R,S)-folinic acid, removing by filtration the salt which separates out, which consists predominantly of the corresponding (6R)-folinates, and isolating the desired (6S)-folinate from the filtrate.

Abstract: For the preparation of 5,10-methenyl-(6R)-, 5-formyl-(6S)- or 5-methyl-(6S)-tetrahydrofolic acid or salts thereof, 5,10-methenyl-(6R,S)-tetrahydrofolic acid, the inner salt thereof or one of the salts thereof with strong acids is subjected to diastereomer separation by fractional crystallization and, if desired, the resulting 5,10-methenyl-(6R)-tetrahydrofolic acid is converted by treatment with a hydrolyzing agent into 5-formyl-(6S)-tetrahydrofolic acid or by treatment with a reducing agent into 5-methyl-(6S)-tetrahydrofolic acid, and the resulting free acid may be converted into one of its salts by treatment with a base.