The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 23, 1991
Filed:
May. 30, 1990
Astra Pharmaceutical Production Aktiebolag, Sodertalje, SE;
Abstract
A process for preparing S-metoprolol of the formula ##STR1## or a salt thereof, with high enantiomeric purity, is described, whereby a (S)-5-hydroxymethyl-3-isopropyloxazolidin-2-one sulfonic acid ester of the formula ##STR2## is prepared, and further reacted with 4-[2-methoxyethyl]phenol of the formula ##STR3## and the resulting intermediate of the formula ##STR4## is hydrolysed to S-metoprolol, and whereby the (S)-5-hydroxymethyl-3-isopropyloxazolidin-2-one sulfonic acid ester of formula II is prepared by reacting (S)-3-isopropylamino-1,2-propanediol of the formula ##STR5## with a chloroformic acid ester of the formula ##STR6## wherein R' is an alkyl group having 1-3 carbon atoms or a phenyl group, to the formation of (S)-5-hydroxymethyl-3-isopropyloxazolidin-2-one of the formula ##STR7## which is reacted with an activated sulfonic acid of the formula ##STR8## wherein R' is an aryl group such as tolyl and X is a halogen such as Cl, to formation of the ester of formula II, which when required is enriched with the (S)-enantiomer by crystallization.