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US H2,154 H1Granted
Process for preparing R- and S-isomers of (R)-5-(2-( (2-(2-ethoxyphenoxy)ethyl)amino)propyl)-2-methoxybenzenesulfonamide
AssigneeFarmak, A.S.
InventorsPavel Hradil, Miroslav Urbasek, Lubomir Kvapil, Petr Slezar
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Abstract
A process for preparing optically pure enantiomers of R-(−)tamsulosin of formiula Ia and S-(+)tamsulosin of formula Ib by resolving racemic tamsulosin of formula I by means of (IR)-(−)-camphor-10-sulfonic acid and (1S)-(+)-camphor-10-sulfonic acid, resp., in an environment of organic solvents, water or mixtures thereof.
Claims5
A process for preparing optically pure enantiomers of (R)-5-(2-((2-(2-ethoxyphenoxy)-ethyl)amino)propyl)-2-methoxybenzenesulfonamide [R-(−)-tamsulosin] of formula Ia
- and (S)-5-(2-((2-(2-ethoxyphenoxy)-ethyl)amino)propyl)-2-methoxybenzenesulfonamide [S-(+)-tamsulosin] of formula Ib
- comprising:
- (a) the resolution of racemic tamsulosin of formula I
- by the treatment with (1R)-(−)-camphor-10-sulfonic acid and (1S)-(+)-camphor-10-sulfonic acid, resp., in an environment of organic solvents, water or mixtures thereof;
- (b) further purification of the crystallized salt of R-(−)-tamsulosin or S-(+)-tamsulosin by crystallizing form organic solvents, water or mixtures thereof, until the desired optical purity is obtained;
- (c) from the salt of R-(−)-tamsulosin or S-(+)-tamsulosin is released, by treatment with alkalis, the base of formula Ia or the base of formula Ib, resp.
3 more elements
A process which comprises:
- (a) preferentially precipitating one diastereomeric camphor sulfonate salt of tamsulosin from a solution containing a pair of diastereomeric camphor sulfonate salts of tamsulosin to form diastereomeric enriched precipitate and diastereomeric enriched solute.
Dependencies are inferred from the claim text.