摘要:
Process for the synthesis of R(+)α-lipoic acid comprising the following stages: a) Salifying of racemic 6,8-halo-octanoic acid with S(-)α-methylbenzylamine; b) separation by filtration of the crystallized diastereoisomeric salt of R(+)6,8-di-halo-octanoic acid-S(-)α-methylbenzylamine; c) purification by re-crystallization of the diastereoisomeric salt of R(+)6,8-di-halo-octanoic acid-S(-)α-methylbenzylamine; d) separation of the diastereoisomeric salt to obtain R(+)6,8-di-halo-octanoic acid by reation of said salt with strong mineral acids in an aqueous solution with a dilution between 2 and 10% by weight; e) esterification of R(+)6,8-di-halo-octanoic acid to obtain the corresponding alkyl ester; f) reaction of the alkyl ester of R(+)6,8-di-halo-octanoic acid in an organic solvent with an aqueous solution of alkali disulfide in presence of a compound for phase transfer catalysis; g) hydolysis of the ester of R(+)α-lipoic acid.
摘要:
Process for the synthesis of R(+)α-lipoic acid comprising the following stages: a) Salifying of racemic thioctic acid with R(+)α-methylbenzylamine; b) separation by filtration of the crystallized diastereoisomeric salt of R(+)α-lipoic acid-R(+)α-methylbenzylamine; c) purification by re-crystallization of the diastereoisomeric salt of R(+)α-lipoic acid-R(+)α-methylbenzylamine, in which the re-crystallization solvent consists of a mixture of non-polar/polar solvents; d) separation of the diastereoisomeric salt to obtain R(+)α-lipoic acid by reaction of said salt with acids selected from the group consisting of aliphatic hydroxy-carboxylic acids having 3 to 6 carbon atoms and aqueous phosphoric acid.
摘要:
A process for the preparation of 1,3-dimethyl-5-hydroxy-oxindole of formula (II) which comprises the reaction of 4-(N-methylamino)phenol with 2-halogen-propinol chloride and cyclization of the resulting compound in the presence of Lewis acids, and the conversion thereof to eserethole.
摘要:
The subject-matter of the present invention is a novel, non-salified ivabradine solid form, in particular an ivabradine form adsorbed on an inert carrier. The subject-matter of the invention is also a process for preparing said solid form, its use in therapy and pharmaceutical compositions comprising it.
摘要:
The present invention relates to an enantioselective enzymatic process for the preparation of an optically active 3-hydroxypiperidinecarboxylic acid derivative.