FIELD: chemistry.
SUBSTANCE: invention relates to organic chemistry and specifically to a method of producing optical isomers of (R)-(-)- and (S)-(+)-meta-chlorobenzhydrylamine. Method involves rubbing racemic meta-chlorobenzhydrylamine with optically active tartaric acid in the absence of a solvent for at least 30 minutes at room temperature. Method is characterized by grinding racemic meta-chlorobenzhydrylamine with 50 mol% (S,S)-(-)-tartaric acid, then a nonpolar solvent is added to the reaction mass, mixed until dissolving unreacted (R)-(-)-meta-chlorobenzhydrylamine, crystalline precipitate of tartrate is filtered out and washed on filter by non-polar solvent from unreacted amine. Obtained (S)-(+)-meta-chlorobenzhydrylamine (S,S)-(-)-tartrate is neutralized with an inorganic base prior to alkaline reaction, is extracted with a non-polar solvent, the organic layer is separated, the obtained extract is dried, the solvent is distilled from the extract and (S)-(+)-meta-chlorobenzhydrylamine is obtained. Non-polar solvent is distilled from the filtrate to obtain (R)-(-)-meta-chlorobenzhydrylamine, which is repeatedly grinded with less than 50 mol% amount of (S,S)-(-)-tartaric acid until disappearance of tartaric acid and (S)-(+)-meta-chlorobenzhydrylamine (S,S)-(-)-tartrate. Then non-polar solvent is added to reaction mass, mixed until dissolution of unreacted (R)-(-)-meta-chlorobenzhydrylamine, crystalline precipitate of tartrate is filtered out and washed on filter by non-polar solvent from unreacted amine. Nonpolar solvent is distilled from the filtrate to obtain enantiomerically enriched (R)-(-)-meta-chlorobenzhydrylamine. Amine enrichment procedure is repeated until constant value of its specific rotation is established.
EFFECT: disclosed method enables to carry out the process in the absence of a solvent at room temperature, reduce its duration and increase the enantiomeric excess of the obtained amines.
1 cl, 1 dwg, 1 ex
